Rebuilding Gear Case of 48SPL-Part 1

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Oldslowandugly
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Rebuilding Gear Case of 48SPL-Part 1

Postby Oldslowandugly » Sun Jan 02, 2022 9:01 pm

I have two 48SPL motors and both leaked water into the gearcases. The saltwater case is frozen solid and I can't get it apart. The freshwater case I am taking apart slowly and carefully. At everythingoutboards.com there are compilations of special tools and parts for servicing older OMC outboard engines, and from them I identified all the special tools I needed to rebuild the gearcases. I found most [of the tools needed to rebuild the gear case could be purchased] at very good prices [by bidding on them at auction websites].

IMPORTANT: before the shift rod is unscrewed from the shift lever, the shift rod should be screwed all the way down while counting the turns. You will need this measurement when you reassemble the parts later. There is an expensive and hard to find tool that measures the shift rod height. Counting the turns and returning the rod to the same position eliminates the need for that tool. Of the two shift rods I have unscrewed, one was 10 turns and the other was 10-1/4 turns.

Moderator's Note: this thread is split into two parts. Part 2 is available at

https://continuouswave.com/forum/viewtopic.php?f=6&t=6914
Last edited by Oldslowandugly on Tue Jan 04, 2022 4:39 pm, edited 1 time in total.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Mon Jan 03, 2022 9:52 am

I am having a very hard time extracting the propeller shaft bearing/seal housing from the saltwater gearcase. The recommended puller suffered a broken bolt from the strain. I now have a chain wrapped around the internal cross bars and an automotive grade gear puller clamped to the chain. I have exerted tremendous force, while heating the gearcase with a torch and oiling the inside. It will not budge. Any ideas?
Last edited by Oldslowandugly on Tue Jan 04, 2022 4:36 pm, edited 1 time in total.

Jefecinco
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Re: Rebuilding Gear Case of 48SPL

Postby Jefecinco » Mon Jan 03, 2022 10:38 am

I assume you have tried all the spray products recommended for loosening stuck fasteners. PB Blaster has been more useful in my experience than several others. Having said that I was ultimately unsuccessful in removing the steering wheel from it's shaft on our Sport 13.

When attempting to remove the track sprocket from a bulldozer we were unsuccessful. We had the Cat designed hydraulic puller and had put the maximum pressure on the puller. We heated the sprocket center as much as we dared and the sprocket remained on the drive axle. In frustration someone gave the shaft a big whack with a sledge hammer and the sprocket finally popped off.

Try using a brass drift pin or other soft alternative to pound on the gear case close to the bearing/seal. That and some PB Blaster and heat may help.
Butch

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Mon Jan 03, 2022 11:51 am

Yeah Butch I tried that too. I whacked the sides with a machinist hammer as hard as I dared. Nothing. I am at the point of carefully cutting the case open so as not to damage the parts inside. I have another spare empty gearcase housing but on that one the pinion and forward bearings are rusted stuck. I just ordered the special tools to remove those. That outboard site was super helpful in identifying the tool part numbers. If I can first get those rusted bearings out of the spare gearcase then I am free to cut open this stuck one.

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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Mon Jan 03, 2022 11:18 pm

My upper bearing carrier extraction tool came today. It is an OMC # 387206 and it clamps around the driveshaft to press it up and out, taking the bearing carrier with it. But the FSM shows a set screw that secures to the water pump impeller flat on the driveshaft. This tool does not have that set screw even though it is the exact tool part number. Maybe it is a superseded model that clamps the shaft tight enough to get it out. I think I will take my drill press and drill a hole and tap it for the set screw. That way even if it slips it can't get past the impeller flat and will raise them up.

Image
Fig. 1. OMC #387206 Driveshaft removal tool
Last edited by Oldslowandugly on Tue Jan 04, 2022 7:08 pm, edited 3 times in total.

Don SSDD
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Re: Rebuilding Gear Case of 48SPL

Postby Don SSDD » Tue Jan 04, 2022 6:05 am

I haven’t done this on a lower unit and don’t exactly understand the details but I have pulled lots of things like steering wheels and other items with a similar mechanical setup. When they stick like this, I have the puller tightened as much as I think it can stand for pressure and they hammer on the end of the shaft, not on the bearing. I use a big hammer and a block of wood so as not to damage threads. If that doesn’t work I put the nut back on the shaft as far as it will go while still protecting the threads and give the nut/end of the shaft a very solid whack with a big hammer. It has always worked. I’ve soaked with pb blaster first and used heat sometimes, propane only.
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Jan 04, 2022 11:09 am

Don that has always worked for me on stuff that is solid and secure, like a steering wheel, flywheel, or wheel hub. It is always a shock when the flywheel leaps off the crankshaft after whacking it with a BFH. But the gearcase is aluminum and fragile. The forward gear bearing is about a foot deep in a four inch round blind hole. You can't get a torch in there and the bearing race is sitting on a ledge that you can't get behind. The factory tool gets behind it somehow and pulls it out. If I can get one I will figure out how this works.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Jan 04, 2022 4:31 pm

Today I used the driveshaft removal tool on the freshwater gearcase. I drilled and tapped the tool for a 3/8" set screw like the FSM says should be there. It clamps around the driveshaft.

I pulled the driveshaft, the upper bearing, and the seal carrier up and out while disengaging the pinion nut from the driveshaft.

The pinion nut is a press fit and this tool easily popped it right off.

Once the driveshaft is out the forward gear and bearing and shims can be removed. I tie-wrapped both the forward and reverse gears to their respective bearings and shims so they don't get mixed up.

Then I removed the leaky seals that started this whole project. I used a common automotive seal pry tool to carefully get all the seals out.

Now the gearcase and all the parts are soaking in #2 oil, an excellent non-flammable solvent.

IMG_0253.JPG
Fig. 2. Driveshaft removal tool
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IMG_0254.JPG
Fig. 3. Bearing and seal carrier removed.
IMG_0254.JPG (188.27 KiB) Viewed 13178 times
Last edited by Oldslowandugly on Tue Jan 04, 2022 7:07 pm, edited 2 times in total.

jimh
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Re: Rebuilding Gear Case of 48SPL

Postby jimh » Wed Jan 05, 2022 8:36 am

I noticed in Figure 2 that you added the set screw that was not on the original tool as seen in Figure 1. I would have thought that the circumferential pressure of two halves of the tool pressing onto the drive shaft would have been sufficient to keep it in place when applying upward pressure.

Did the set screw leave a mark on the drive shaft?

Did the two steel bars that are shown in Figure 2 placed under the tool come with the tool as purchased? They look like a good method to prevent the upward-lifting screws on the tool from damaging the workpiece.

ASIDE: nice photography in Figures 2 and 3.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Jan 05, 2022 1:35 pm

I drilled and tapped the tool for the set screw because the tool described in the [factory service manual] had one. I did that because on my saltwater gearcase that bearing carrier would not come out and needed to be chiseled apart. I was expecting the worst but it turned out this freshwater gearcase was not corroded at all. The carrier extracted easily as it should.

The set screw did not damage the shaft. That spot [where the set screw bears against is] where the pump impeller wedge sits.

387206.jpg
Fig. 4. OMC factory 387206 driveshaft extractor tool with set screw
387206.jpg (103.86 KiB) Viewed 13118 times


The factory tool required a plate that sat on the gearcase to protect it as mentioned. None of the factory tools I found included that plate. The plate is a separate part number and I could not find one.

325867_.jpg
Fig. 5. OMC 325867 extractor tool backing plate to protect gearcase
325867_.jpg (9.14 KiB) Viewed 12564 times


The aftermarket tool made by Precision Tools did include it. I had a similar plate but it would have needed the hole enlarged. I also had the two stainless bars handy to protect the gearcase and they worked just fine.

jimh
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Re: Rebuilding Gear Case of 48SPL

Postby jimh » Wed Jan 05, 2022 9:26 pm

Thanks for explaining the set screw. I infer that you mean the shaft is rotated so the set screw will bear against the flat part of the shaft where the key for the water pump impeller is located.

dtmackey
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Re: Rebuilding Gear Case of 48SPL

Postby dtmackey » Wed Jan 05, 2022 10:41 pm

Did the lower unit need a rebuild or just new seals? I chuckle at the shop manuals and the tools needed to replace the most common failure - prop shaft seals. A simple trick to the expensive tools and removing the bearing carrier is to screw 2 - 3 drywall screws into the seal on the outer edge away from the shaft and then pry them with a set of end cutter pliers and the seals pop right out. To install the new seals a piece of PVC plumbing pipe sized to the seal is perfect to seating the new seals. I've done countless seals with this method and never bothered with the tools. I can do prop shaft seals in 5 mins or less with this method.

D-

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Jan 06, 2022 8:11 pm

That sounds like a good plan if the shafts are smooth. I have two gearcases. One is saltwater welded together and one is normal freshwater use rebuild-able. Both needed all new seals. On the saltwater case the seals and their casings were corroded away to nothing. Worse, there are deep grooves worn into the shafts where the seals ride. That normally would require new shafts because the seals won't seal at the grooves. I have a fix where I clean and fill the shaft grooves with Marine Tex and then wet-sand that down flush with the shaft surface. If you do it right the shaft is as smooth as a new one and the seal won't leak. But it requires that the shaft be out of the gearcase so I am trying to extract them now. The freshwater gearcase is coming apart easily. It also has some grooves in the shafts but not as bad as the saltwater parts. I learned the hard way that putting new seals on grooved shafts is a recipe for disaster. No matter how small, the grooves cut the seal lips and they fail early.

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Re: Rebuilding Gear Case of 48SPL

Postby jimh » Fri Jan 07, 2022 12:20 pm

A complete rebuild of an OMC gearcase (30-HP model) is demonstrated very nicely in the three-part presentation linked below. The mechanic does a very good job of explaining each step. He also comments about ways to work around the need for factory special tooling to perform the work. After watching the demonstration, I am impressed with the crafty design that goes into an outboard engine gear case that allows all the work to be done through the propeller hub opening.

The mechanic-presenter in these demonstrations is from an Australian shop, DANGAR MARINE. He seems to know his way around old OMC outboard engine gear cases.

The three parts in order at found at:

https://www.youtube.com/watch?v=_JXaJ4PZMfc
https://www.youtube.com/watch?v=sGXTkRoumgk
https://www.youtube.com/watch?v=16KaFpxgqsk

Don SSDD
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Re: Rebuilding Gear Case of 48SPL

Postby Don SSDD » Fri Jan 07, 2022 2:21 pm

I’ve used DANGAR demonstrations when working on my Honda, Evinrude, and maybe a Yamaha. His presentatoin are very helpful; he explains things well and in detail.
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Fri Jan 07, 2022 5:27 pm

[A youtube presentation from DANGAR MARINE] inspired me to try to bend my skeg.

I liked the 30-HP gearcase rebuild--but it is much simpler than the rebuild on the 40-48-50 models.

I learned on the old split-gearcase 30-HP engines. I could rebuild one in my sleep. I did not have a single expensive factory tool. Instead I used correct-size sockets and other home made tools. But these thru-hub gearcases are mind boggling to me.

Below is a link [to another presentation from DANGAR MARINE on the topic of HOW TO REPLACE PROPELLER SHAFT SEALS that was] suggested to me by dtmackey:

HOW TO REPLACE PROPELLER SHAFT SEALS
https://www.youtube.com/watch?v=c14ixpVXrZ0

The demonstrator circumvents the gearcase tear-down. He also warns against scratching or damaging a shaft or else the seals will fail.

[On the SPL48 engine that is the topic of this thread the propeller] shafts are grooved too badly to ignore, and that is why I am taking apart my gear case.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Sun Jan 09, 2022 7:05 pm

The pinion gear bearing tools arrived.

tool.jpg
Fig. 6. Pinion bearing tool assembled to remove bearing
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IMG_0262_01_.jpg
Fig. 7. Pinion bearing tool assembled to install bearing
IMG_0262_01_.jpg (14.31 KiB) Viewed 12569 times


I use it to drive out the bearing from the bottom of the driveshaft cavity into the gearcase.

My "spare-parts" gearcase had both the pinion, the forward gear, and the propshaft bearings still installed when I received it. They were very rusty so I drenched them in penetrating oil for a long time before trying to remove them. The factory service manual says if [the pinion, the forward gear, and the propshaft bearings] are removed for any reason they must be replaced.

I installed the tool and used a small machinist hammer to drive the pinion bearing down into the lower gearcase.

IMG_0263_01_.jpg
Fig. 8. Pinion bearing tool used to locate pinion bearing properly
IMG_0263_01_.jpg (28.09 KiB) Viewed 12568 times


Because the pinion bearing was very rusty it took many careful blows with the hammer.

The same tool is used to install the new bearing. The pinion bearing is only driven in one direction: from the top down, with hammer blows on the tool. Once assembled correctly, the tool is also used to locate the pinion bearing in the proper place in the cavity.

Then the retaining screw is installed in the side of the gearcase to secure it. I suppose you could use a section of pipe the correct diameter to drive the bearing. But you would first need to measure precisely the depth of the old bearing from the top of the case to locate it correctly. I am still waiting on my new pinion bearing. The correct tools to do this operation are part of a large expensive tool kit. I merely used the FSM to determine which ones were needed for a 48 hp and found those tool parts on the web as inexpensively as I could. Having the correct tools does make the job go easier.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Sun Jan 09, 2022 8:19 pm

Below is the rusty old bearing as it came out on the tool.

IMG_0261_01.jpg
Fig. 9. A rusted bearing from a used gear case.
IMG_0261_01.jpg (13.29 KiB) Viewed 12558 times


This part was still in the used gearcase I bought. I would not even think of using it when I transfer the parts from my saltwater gearcase.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Jan 12, 2022 2:28 pm

I finished de-greasing the parts from the freshwater gearcase. At the 20-degrees-F air temperature yesterday, there is very slow evaporation, thus minimal fumes. I had let them soak for a week in number two oil--the same as Diesel fuel. The parts came out very clean. I left the pinion and forward bearings in place as they were still serviceable.

IMG_0265.JPG
Fig. 10. All the parts from the 48hp gearcase
IMG_0265.JPG (207.3 KiB) Viewed 12169 times


IMG_0267.JPG
Fig. 11. The 48SPL lower gearcase and forward bearings
IMG_0267.JPG (166.53 KiB) Viewed 12169 times


IMG_0268.JPG
FIg. 12. The 48SPL upper bearing and driveshaft cavity. Pinion bearing at bottom.
IMG_0268.JPG (155.51 KiB) Viewed 12169 times

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Jan 12, 2022 3:56 pm

Now I can concentrate on fixing the grooves worn in the shafts where the seals ride.

The first step in fixing the grooves is to scour all the dirt and corrosion from the worn groove areas with a medium grit abrasive pad on a fast drill. You can usually see the scratches, but use your fingernail to test . You will feel a scratch that you cannot see.

Next, thoroughly de-grease the area with a product like Brake Clean that does not leave a film behind.

Cleanliness is key to the Marine-Tex adhering properly. Mix the Marine-Tex according to the directions in the box. Apply Marine-Tex to [fill] the grooves completely.

IMG_0269.JPG
FIg. 13. Prop and drive shaft grooves filled with Marine Tex.
IMG_0269.JPG (217.11 KiB) Viewed 12155 times


Don't worry about applying too much Marine Tex as you will be removing 99-percent of it. Let Marine-Tex harden at least 24-hours.

dtmackey
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Re: Rebuilding Gear Case of 48SPL

Postby dtmackey » Wed Jan 12, 2022 5:54 pm

Oldslowandugly wrote:Don't worry about applying too much as you will be removing 99% of it anyway.
It's almost as if you've seen me do drywall mudding.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Jan 13, 2022 11:11 am

I've done my share of spackling and shadetree bodywork, too.

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Re: Rebuilding Gear Case of 48SPL

Postby jimh » Thu Jan 13, 2022 2:12 pm

If cured MARINE-TEX "sands like wood" as its label says, I don't think it would be a good surface for a seal to bear onto. The seal may wear away the MARINE-TEX

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Jan 13, 2022 4:23 pm

Jim, regardless what the advertising says, Marine-Tex does NOT sand as easily as wood. If fact you would be warned not to overdo it because sanding down Marinre-Tex by hand can be an absolute chore. I get off most of the Marine-Tex with a Ny-lock sanding disc. Once I am close to where I need to be I polish down the Marine-Tex with wet-dry sandpaper.

On something round like a shaft, Intake a strip of wet-dry paper and hold the ends while I run the sandpaper back and forth like I were polishing the toes of a shoe. I use this technique on automotive crankshaft dampener and rear end companion flange seals. They see a lot more usage and road debris so those seals can dig very deep grooves. On an outboard motor the dirt on the seals doesn't scratch as much, but any water intrusion is serious business

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Sat Jan 15, 2022 7:07 pm

I accomplished a lot today. I sanded the Marine Tex off of the shafts with the sanding disc, then finished with the sandpaper strips.'

IMG_0274.JPG
Fig. 14. Nylon sanding disc for cleaning the gasket surfaces and bearing carriers.
IMG_0274.JPG (196.41 KiB) Viewed 11767 times


The inside prop shaft seal groove was worse than the outer groove. The inner groove was deep, wide and well defined, while the outer was shallow and inconsistent. Both grooves and some pockmarks are now filled.

I then used the OMC bearing removal/install tool to pull the two rusted forward gear bearings out of the parts case. I don't see how anyone could remove them without this robust tool. OTC makes it. The puller head folds to get behind the bearings in a blind hole. Then it flips around to grab the bearing races from behind. Even with lots of penetrating oil it was a struggle to remove them.

IMG_0276.JPG
Fig. 15. Bearing tool in the pulling position.
IMG_0276.JPG (150.02 KiB) Viewed 11767 times


Now that all the old rusted bearings are removed from the parts case I can go about cleaning it up and repairing some damage it suffered somewhere. I am also cleaning the gasket surfaces and bearing carriers on the freshwater case for the re-build.

IMG_0277.JPG
Fig. 16. Bearing tool in the folded position.
IMG_0277.JPG (145.05 KiB) Viewed 11767 times
Last edited by Oldslowandugly on Sat Jan 15, 2022 11:21 pm, edited 2 times in total.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Sat Jan 15, 2022 7:12 pm

Here is the prop shaft with the grooves rough sanded by machine and then sanded down smooth by hand.

IMG_0270.JPG
Fig. 17. Rough sanded by machine.
IMG_0270.JPG (163.3 KiB) Viewed 11766 times


IMG_0271.JPG
Fig. 18. Smooth finish by hand.
IMG_0271.JPG (149.66 KiB) Viewed 11766 times

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Sun Jan 16, 2022 5:28 pm

IMG_0278.JPG
Fig. 19. Pinion gear to upper bearing carrier tool in position with a .030" feeler gauge.
IMG_0278.JPG (89.36 KiB) Viewed 11710 times


Show above is the tool used to measure the upper bearing carrier to pinion gear distance. OMC wants to see .030" clearance. This tool is calibrated the exact distance minus the .030".

I assembled the roller bearing, spacers, shims, upper bearing carrier, and properly torqued pinion gear. The tool fits exactly with a .030" blade type feeler gauge. This sets the pinion gear in the proper mesh relationship to the gears in the gearcase. It is also part of a large expensive tool kit. I found the exact gauge for my 48SPL on the web for an extremely reasonable price.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Jan 18, 2022 4:41 pm

Before starting the rebuilding, I did thread chasing and final clean-up. An amazing amount of dirt gets into the nooks and crannies while working.


IMG_0279.JPG
Fig. 20. Gearcase wedged into wooden arms on the workbench while chasing all the threads.
IMG_0279.JPG (158.45 KiB) Viewed 11457 times

I can advise a simple addition to any workbench. I bolted two short sections of two-by-four to the underside of the workbench. Now the gearcase can slip into the gap and be totally supported for working on.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Jan 19, 2022 6:26 pm

I put the new seals into the propeller shaft and drive shaft bearing carriers. I did not have, nor could I locate, the proper seal installation tools. I found that a brass lavatory sink tailpiece fit the propshaft seal perfectly. A 13/16-inch deep-socket fit the driveshaft seals perfectly.

IMG_0281_.jpg
Fig. 21. Lower-left: socket for seating seals; upper center pipe for setting seals; lower right quad ring seals.
IMG_0281_.jpg (25.99 KiB) Viewed 11252 times


Rather than slam them with a hammer I used my big bench vise to carefully press the seals in.

According to an OMC factory bulletin, the double seals previously used on the propshaft have been superceded by a double lipped single extended lip seal. An advantage to this is that the single seal can be located on fresh metal surface away from the repaired grooves on the shaft.

The instructions that came with the new seal called for OMC Deep Penetrating Lubricant instead of the usual gasket sealer. I used Gibbs oil which is similar and leaves a protective coating.

The driveshaft double seals still called for OMC Gasket Compound which I did not have. I know the equivalent is Permatex Aviation Gasket Sealer which I did have. However I prefer Permatex Ultra Black for anything involving oil, water, or other fluids. It has never failed me.

When driving in the seals be aware that they must go in perfectly straight so don't trust your eyes. I used a machinist ruler and a straightedge to measure the seal depth at four points around the carriers. Some minor adjustments were required.

IMG_0282.JPG
Fig. 22. Measuring seal depth.
IMG_0282.JPG (160 KiB) Viewed 11385 times

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Jan 20, 2022 6:36 pm

I put the forward gear, thrust bearing, and spacer into the gearcase. The OMC roller bearing grease holds the parts in place while you work.

Next, the driveshaft bearing carrier goes on the driveshaft and the whole assembly is placed into the gear case. Wrap some masking tape around the driveshaft splines so as not to cut your new seals. Don't push the carrier all the way into place yet. At the same time you must place the pinion gear inside the gearcase and on to the end of the driveshaft.

I found I had to lift the driveshaft up and out of the way to get the pinion gear past it. Some gearcase oil goes on the threads and then the pinion nut gets torqued on. Once that is done then you can push the bearing carrier all the way down into the gearcase and bolt it in place. To get the carrier all the way in was difficult, but tightening the bolts finished the job.

I used some Ultra Black on the carrier to gearcase mating surfaces and anti-seize on the bolt threads. Do NOT use sealer on the carrier sides or it will never come out again.

Next. place the shifter rod O-rings on the shift rod cover, then the O-ring and bushing onto cover, then sliding them all onto the shifter rod. Grease the O-rings with OMC Triple Guard grease and use Adhesive M or 3M 847 to seal the O-ring bushing to the cover.

Screw the shifter lever onto the end of the shifter rod. Set aside.

IMG_0286_.jpg
Fig. 23. Soft-focus on shifter lever engaged to shifter cradle on end of propeller shaft, outside of the gear case to illustrate the eventual assembled position.
IMG_0286_.jpg (19.89 KiB) Viewed 11164 times


Now we can insert the propeller shaft into the gear case with the shift cradle in place. The trick is to place the shifter cradle onto the end of the shifter dog shaft, using some OMC roller bearing grease to hold it in place. This is key, or it will slip off and it will never stay in place.

What is being done is inserting the propeller shaft, with the cradle attached, into the gear case--all the way in. You will see the cradle from above looking into the shifter rod cavity. Then you drop the shifter rod with the shifter lever down into the shifter cavity and the lever must engage the shifter cradle. This is critical to get right

Once you are sure the parts are assembled properly, you screw the shift lever pivot screw into the side of the gearcase being sure to insert it through the holes in the shift lever. Use some Lok-tite on the threads and seal the screw O-ring. If you did it right, now the prop shaft can not be removed and you can shift the clutch dog by hand using the shifter rod.
Last edited by Oldslowandugly on Fri Jan 21, 2022 9:18 pm, edited 2 times in total.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Jan 20, 2022 6:44 pm

[Moderator's note: I moved this very important first step in disassembly to be located much earlier in the narrative, instead of at the end of the narrative.]

dtmackey
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Re: Rebuilding Gear Case of 48SPL

Postby dtmackey » Fri Jan 21, 2022 12:28 pm

Nice presentation of the steps.

ASIDE: One thing I noted is the cleaning of the surfaces with an abrasive tool. Not that you would, but vapor blasting is one of the best ways to clean metal of oxidation while not harming the surface at all. I've always wanted one, but the $3,500 to over $5,000 price kept me out of that game, until I came across plans and built one. Now I run just about anything that will fit through the blaster where restoration to a new finish is desired.

The blast media is a wet glass bead mix and does not damage or remove the original metal, but cleans dirt, grease, oxidation and more. Wet blasting is key since the water keeps the contact surface temperature low and the water has a shock absorbing property.

Here's a heavily corroded cast aluminum piece as an example.

Image
Fig. 24. An aluminum casting. The upper half is before cleaning; the lower half has been cleaned with vapor blasting.

D-

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Fri Jan 21, 2022 5:20 pm

ASIDE: Nice process. How did you build it? I wanted to send the bare gearcase out for hot tanking. No one near me does that anymore. Only for ferrous metals. I have a dry blast cabinet but I don't use it for aluminum.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Jan 25, 2022 6:36 pm

I had the prop shaft bearing carrier dry-fitted and ready to go. I applied sealer to the O-ring and flange. But when I went to insert it into the gearcase it would not go in the last half inch.

Do not be tempted to bang it in! It may need a slight tap, but not a forceful blow.

I had to remove it, clean it again, and diagnose the problem.

I found that the roller thrust bearing and thrust washer MUST be seated properly in their respective spots. You use the OMC roller bearing grease to hold them in place. If you just drop the reverse gear in and it lands hard, the thrust bearing can be bounced out of place. The next time I carefully lowered it in with a long magnet-on-a-stick.

The bearing carrier end has the thrust washer held in place with the grease. If you lower it in, and then raise it again, the washer sticks to the bearing and can move out of place. Either of these can cause the carrier to not fit all the way in.

The other thing is to be SURE that the clutch dog is in the forward gear position. Pour just enough gearcase oil down inside the gearcase so that the clutch dog and shifter lever are lubricated. Then you can shift the dog into forward gear by pushing down on the shifter rod. Test by turning the driveshaft clockwise by hand. The propeller shaft should also turn clockwise. That way the clutch dog is all the way into the forward gear and the dog tabs cannot interfere with the reverse gears tabs.

To re-position the reverse gear is difficult because of the roller thrust bearing. Figure 25 shows the roller thrust bearing is on the reverse gear, and the thrust washer is on the bearing carrier. OMC roller bearing grease is securing them.

Fig25_.jpg
Fig. 25. The roller thrust bearing and thrust washer held in place with OMC grease.
Fig25_.jpg (56.97 KiB) Viewed 8330 times

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Mon Jan 31, 2022 9:47 pm

I can't get the propeller bearing carrier into the gearcase when the O-ring is installed. Otherwise it fits inside fine. Further study is indicated.

dtmackey
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Re: Rebuilding Gear Case of 48SPL

Postby dtmackey » Tue Feb 01, 2022 10:40 pm

Oldslowandugly wrote:I can't get the propeller bearing carrier into the gearcase when the O-ring is installed. Otherwise it fits inside fine. Further study is indicated.
Grease it up and give it a shot, some are a very snug fit.

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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Feb 02, 2022 10:42 am

I thought of using grease, but sealant is supposed to be used on the O-ring area. Sealant and grease don't play well together.

I cleaned off all the sealer--AGAIN--and tried a dry fit. [The propeller bearing carrier] went into [the gear case housing] all the way with some difficulty. There is a slight ridge inside where the O-ring area is a very tight fit. I am thinking the sealer is keeping the O-ring from seating properly.

If I can rig some sort of press I think I can get [the propeller bearing carrier] seated without bashing it with a hammer.

MarkCz
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Re: Rebuilding Gear Case of 48SPL

Postby MarkCz » Fri Feb 11, 2022 7:56 am

I read your post about winter and walking away from the gearcase rebuild. I hope you don't stay away too long. Your posts and details were very well documented and a great read. Thanks for posting your progress.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Fri Feb 11, 2022 11:06 am

Thanks for the encouragement. Don't worry. There is plenty of Winter left to finish this project.

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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Feb 15, 2022 2:34 pm

Break is over: back to work.

The bearing carrier has a large O-ring that must compress to allow the carrier to seat all the way. This is important because the position of the carrier establishes the position of the reverse gear in relation to the pinion gear as well as clearance at the prop shaft bearing. I knew [something] was not seated properly because the propeller shaft had a half-inch of play at the bearing.

Even on a dry fit to seat the carrier was difficult.

The O-ring bumps up against a ledge where the inside end of the carrier rides. Sealer makes it even harder to get it in.

Fig.26_.jpg
Fig. 26 Carrier with Ultra Black on contact surfaces.
Fig.26_.jpg (31.53 KiB) Viewed 8329 times



I applied the Ultra Black sealer to the O-ring and all carrier surfaces that touch the inner gearcase. In addition to sealing the O-ring I wanted to prevent corrosion of the aluminum parts that contact each other as best I can.

Be sure the propeller shaft seals are well lubricated with OMC Triple Guard grease, and be sure to shift into forward gear.

I took two of the long 1/4-20 extraction screws and screwed them back into the carrier. This way you can handle the carrier without getting the sealer on yourself. As you insert the carrier you need the drain hole to be at the bottom. The screws ease adjustment.

Fig27_.jpg
Fig. 27. This is as far as the carrier will go in because the O-ring is stopped by the ledge. Note the drain hole. This is far as you can by pressing it in by hand.
Fig27_.jpg (24.05 KiB) Viewed 8329 times



I found that a hammer is not the tool for this job. Instead I took a short section of 2-inch-diameter PVC pipe that could slip over the prop shaft and rest on the carrier cross braces. I have an old woodworking adjustable screw clamp that fits from the front end of the gearcase to the end of the PVC pipe. I used the clamp to press the carrier in fully.

Fig28_.jpg
Fig. 28. Improvised woodworking clamp used to press the carrier into the gearcase the rest of the way.
Fig28_.jpg (22.98 KiB) Viewed 8328 times


Once the sealer cures I can test for leaks.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Feb 15, 2022 2:38 pm

Figure 29 shows the bearing carrier when fully seated into the gear case. The outboard end of the bearing carrier will be located about 1/8-inch into the gear case housing. The clamp will press it in very easily. You will know when it hits bottom and is fully seated.

Fig.29_.jpg
Fig. 29. The bearing carrier is fully seated in the gearcase.
Fig.29_.jpg (44.79 KiB) Viewed 8326 times

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Tue Feb 15, 2022 9:48 pm

While waiting for the Ultra Black to cure I turned my attention to the frozen gear case.

To pull out the bearing carried I tried every trick I knew--they all failed. I used my Dremel-tool cutting disc to cut open the gear case housing at the bearing carrier. I used the OMC carrier puller tool to put as much pressure as I dared on the carrier. The OMC carrier puller tool is similar to a steering wheel puller, but the plate is much thicker and stronger. I found some 9-inch-long grade-8 1/4-20 bolts to fit the 40-48-50-HP engines carrier retainer bolt holes.

Fig30_.jpg
Fig. 30. The OMC carrier puller in pulling position. Dremel tool with cutting disc used to cut the housing.
Fig30_.jpg (26.53 KiB) Viewed 8325 times


Fig.31_.jpg
Fig. 31. Closeup of the housing cut to relieve pressure on the carrier.
Fig.31_.jpg (49.91 KiB) Viewed 8325 times


While the tool applied tremendous pulling pressure on the carrier. I carefully cut along the side of the housing. Just as I was getting past the outer carrier flange, I heard a loud pop and the carrier broke loose from the housing. After that it was easy to pull out the rest of the gear case internals with the OMC puller.

Fig.32_.jpg
Fig. 32. The intact bearing carrier finally out of the housing.
Fig.32_.jpg (39.15 KiB) Viewed 8325 times


I found no corrosion at the O-ring flange. The inside of the housing where the outer flange sits was severely corroded. That is why it was stuck so solidly.

Now that I salvaged the bearing carrier without harming it I can take the rest of the parts from this case and use them to re-build the spare gearcase.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Feb 16, 2022 4:39 pm

On February 16, 2022, I removed the rest of the parts from the junk gear case. Using a telescoping magnet-on-a-stick helps in reaching in and grabbing the reverse gear, thrust bearing, and washer.

Before the propshaft can be removed, the shifter pivot screw must be removed from the side of the gearcase. Then the shifter rod seal housing must be removed at the top of the shifter shaft. Then the shifter rod and pivot can be pulled up and out.

As noted above, before unscrewing the rod from the pivot, screw it down into the pivot until it bottoms while counting the turns and writing that down. Then you can re-install the rod later exactly as it was.

Now you can pull the propshaft out of the housing. If it will not come out that means the shifter cradle is hanging up. Try turning the whole case around and jiggling the propshaft so the cradle falls out of the way. The pinion gear must come off before the forward gear can come out. The top of the driveshaft will be turned with a driveshaft socket. I found that a one-size-fits-all adjustable socket will just fit onto the splines and work as well.

Then inside the gearcase you use an 11/16-inch short socket and breaker bar to hold the pinion nut while you turn the driveshaft to unscrew it. The nut will come out with the socket. In this case the upper bearing carrier was already out so I just yanked up on the driveshaft and the pinion gear came off inside the gearcase. Pull the driveshaft all the way out.

Now you can reach deep inside with the magnet and remove the pinion gear, forward gear, thrust bearing, and washer.

I wanted to salvage the bearings, too, so I removed them. Make sure the pinion bearing retainer screw is removed from the side of the gearcase. Then the bearing can be driven down into the gearcase with the proper tool or a section of pipe of the right size. If using pipe be sure to measure exactly the depth of the bearing for later.

The two front forward gear bearings are removed with the OMC tool. It gets behind them and pulls them out cleanly. I see no other way to do that.

Fig33_.jpg
Fig. 33. The pinion gear retainer screw is seen. The open hole is for the shifter pivot screw.
Fig33_.jpg (57.76 KiB) Viewed 8324 times


Fig34_.jpg
Fig. 34. The OMC tool for removing the forward gear bearings.
Fig34_.jpg (12.81 KiB) Viewed 8324 times


Fig35_.jpg
Fig. 35. The OMC tool for removing/installing the pinion bearing.
Fig35_.jpg (30.71 KiB) Viewed 8324 times




Now the gear case is bare and I will use these parts to re-build the spare gearcase I purchased from web sources.
Last edited by Oldslowandugly on Thu Feb 17, 2022 3:48 pm, edited 2 times in total.

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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Feb 16, 2022 4:42 pm

Figure 36 shows all the parts salvaged from the "junk" gear case.They all appear to be reusable. Nothing is broken except for the gear case housing I cut open, and even that can be repaired if really needed.

Fig36_.jpg
Fig. 36. The junk gear case and parts from it.
Fig36_.jpg (70.84 KiB) Viewed 8324 times

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Feb 17, 2022 4:01 pm

The Ultra Black has cured and I tested for leaks on the gearcase. Another problem has emerged. The original double seals on the propshaft were superseded by a single double lipped seal. The instructions that came with the new type seal explicitly warned to NOT use sealer when installing. That did not seem right and I was correct. The new type seal leaks terribly. Not at the propshaft, but at the sides that SHOULD have had sealer. Now I had to again remove the carrier housing and clean it up. I don't know how I can remove the new type seal without destroying it. If I use the carrier bearing to push the seal out- the bearing must be replaced too.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Thu Feb 17, 2022 6:09 pm

I was able to extract the seal without damaging the bearing.

Fig37_.jpg
Fig. 37. The Ultra Black did not cause difficulty extracting the bearing carrier.
Fig37_.jpg (119.83 KiB) Viewed 8262 times



It looks like [the propeller shaft seal is composed of] a very thin steel ring surrounded by a hard rubber molding. and there are two lips with springs behind them.

Fig38_.jpg
Fig. 38. The double lipped seal that leaked air is mostly cast rubber.
Fig38_.jpg (71.69 KiB) Viewed 8262 times


I guess the gear case manufacturer expects the thick rubber on the sides alone to seal [the propeller shaft seal] against the [bearing] carrier--keep dreaming.

As I pumped air into the gearcase for a test, [the propeller shaft seal] blew out as if there were no seal there at all.

Readers should note that the cured Ultra Black sealer I used all around the carrier flanges did NOT interfere with extracting the carrier. I should have used it on the double lipped seal.

Oldslowandugly
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Re: Rebuilding Gear Case of 48SPL

Postby Oldslowandugly » Wed Feb 23, 2022 5:04 pm

I now have the old-style seals.

I found that the bearing in the carrier is the same as the pinion bearing. So the same bearing tool can be used to install the inner carrier seal.

fig39_.jpg
Fig. 39. Inner and outer seals back-to-back.
fig39_.jpg (40.41 KiB) Viewed 8145 times


The smaller part of the tool fits the carrier roller bearing and guides the seal straight in.

The OEM double type seal use two seals- one with the lip facing the oil side of the gearcase. The other lip facing the water outside.

I applied the Ultra Black sealer to the inner seal and drove it in with the bearing tool. Then I partially drove in the outer seal and thought that since the lip faces out and the tool is not an exact fit it might hurt it.

I found an 11/16-inch impact socket fit better, so I used that to drive the outer seal in the rest of the way.


fig40_.jpg
Fig. 40. 11/16-inch impact socket to drive in the outer seal.
fig40_.jpg (21.23 KiB) Viewed 8145 times


The seals fit back-to-back in the carrier so if the inner is flush then the outer will also be flush.

The cavity between the seal lips is filled with OMC Triple Guard grease.

Then I placed the O-ring dry on the carrier and inserted it by hand into the gearcase with no sealer. I then lightly pressurized the case. The seals were so good that the air pressure forced the carrier out of the gearcase. It moved out until the O-ring went past the lip where it then leaked air. That is what I was looking for.

Now I can install the carrier with sealer and see if it holds pressure like it should.


fig41_.jpg
Fig 41. OMC bearing tool to drive in the inner seal.
fig41_.jpg (38.23 KiB) Viewed 8145 times


Moderator's Note: this thread is split into two parts. The thread continues now in Part 2 at

https://continuouswave.com/forum/viewtopic.php?f=6&t=6914