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Author Topic:   Side Mount Hydraulic Steering
jimh posted 07-21-2002 11:33 AM ET (US)   Profile for jimh   Send Email to jimh  
Recently I converted my hydraulic steering from a rather old (c.1985) Teleflex center-mount hydraulic cylinder to a new Teleflex HC5370 side-mount hydraulic cylinder. I plan to publish an illustrated article about this, but until then I can offer this brief posting.

I have also just moved the engines (twin 70-HP) off the transom and mounted them on 10-inch setback brackets (which I will also describe at greater length in the future). This got all of the engine cables out of the motor well, creating the possibility of using that space for other purposes.

The change in steering was done mainly to create a "cleaner" installation and to allow the engines to tilt to the full up position in their new transom brackets. The old hydraulic steering was a center-mounted cylinder. Because of its location in front of the engine, the hydraulic cylinder interferred with the bracket structure when the engine was tilted up. The starboard engine (the one with the steering cylinder) could only be tilted about halfway up.

The old Teleflex cylinder was still working perfectly, but it had to be changed to really take full advantage of the new space in the motor well and to let the engines tilt properly. The old rigging for the steering tangs and the tie bar was also somewhat unusual, although it worked beautifully. This would also need to be re-rigged.

The first step was dismantling the old gear. The high-quality stainless steel hardware was very easy to remove. There was virtually no corrossion anywhere and most components were still in brand-new condition. So it was simple to take this gear off.

I went to the hardware store and got some brass fittings to temporarily plug the ends of the hydraulic hoses from the helm steering pump.

The HC5370 cylinder was purchased from Shoreway Marine (mail-order). Their pricing was excellent; I saved over $100 compared to more well-known catalogue sources. The cylinder was drop-shipped to me directly from Teleflex's Florida factory in a few days.

The cylinder came with an extensive installation manual, but unfortunately 99-percent of the contents are directed at center-mounting cylinders. There is only a single page with just a few simple sentences of instruction for the side mounting device. I had quite a few questions, but I was able to get extensive answers for them from Teleflex via eMail. They were great, just excellent product support, and they answered all my inquiries.

The HC5370 cylinder screws onto the tilt-tube threads of your engine, just like a cable steering device would. The actuator arm extends through the tilt tube and exits the other side, where you attach a DRAG LINK ARM to connect to the STEERING TANG on your outboard, again, just as in a cable steering setup.

To me there are several advantages to this design:
--the hydraulic cylinder is stationary (unlike the center-mount model which moves as the engine pivots) so the hydraulic cables do not need to have slack and lead dress to move around to follow the motion. The cables can be rigged and secured in place.
--the side-mount cylinder is cheaper;
--the existing drag-link arm from the cable steering can be used;
--there is no worry about clearance for tilting up the engine in shallow wells or with brackets.

The only disadvantage is the side-mount cylinder has slightly asymmetrical forces and does not work well with auto pilots, but this is not a concern for most outboard boats.

I mounted the hydraulic cylinder on the starboard side of the port engine. This put the cylinder between the engines, out of harm's way. It also made the cylinder a handy retainer for other cables running across between the engines. (I'll show you a picture later.)

Before installing the cylinder you add the actuator arm extension. It fit like a glove and is secured with a special tapered pin. A thick coating of Mercury 2-4-C grease prepared the actuator rod for insertion in the tilt tube.

Because my old instation did not use the tilt tube, it was still packed with the OEM grease from Yamaha. The grease was in fine shape and I left it in place. You might want to clean and repack the tilt tube with fresh grease at this point.

The threads for the tilt tube on my 1987 engine had a little rust on them. Before installing the cylinder I soaked the tilt tube with a rust penetrant and scrubbed the threads it with an old tooth brush to remove any loosened rust. I coated the tilt tube threads with a liberal amount of anti-seize compound (from an automotive store) to inhibit further rusting. The cylinder threads onto a standard 7/8-inch tilt tube. There is a nylon anti-vibration thread locker built into the tilt tube to keep it from loosening up. That is another example of fine detail in the Teleflex product.

Teleflex includes most everything you need in the cylinder kit, except some pipe sealant. They recommend Loctite PST, but I used some Teflon pipe sealant from the hardware store with apparently good results. (You can get the Loctite PST are West Marine I discovered later.)

As shipped, the HC5370 has only one of the two bleed-tee fittings installed. The cylinder is constructed so that the fitting on the gland end of the cylinder can rotate around to orient it as needed. On the actuator end of the cylinder there are two pre-drilled and tapped holes, 180[°] apart. After you thread the cylinder onto the tilt tube, you pick the hole nearest the top for the bleed-tee; the other hole is sealed with a plug.

Actually, mine came with the plug already installed in one hole, but as it happened that turned out to be the topmost location in my installation. I had to remove the factory installed plug; I thought I was going to break the allen wrench. That baby was in there tight!

I swapped the plug into the other hole and installed the bleed-tee fitting. Then I connected the hydraulic hoses from the steering pump and dressed and rigged them for a neat installation.

The next step was to refill and bleed the hydraulic system. To facilitate this Teleflex includes a fill fitting for the steering pump, a length of hose, and a fitting which screws onto the neck of the oil bottle. They even include a tack for punching a hole in the filler bottle to allow air to escape. I told you they give you almost everything you need for this installation.

The fill and bleed technique is very well illustrated and explained in the instruction booklet, so I won't elaborate here. At the bleed end, I added a 1-foot length of clear tubing to the bleed fitting, taped to an old soda bottle as a basin to receive the bleed oil. The hose and bottle can hang from the bleed fitting, freeing you up to quickly tighten the bleed screw when you have evacuated all the air from the system.

Bleeding the system is just a matter of following the directions. With a helper turning the helm wheel, I bled the system without spilling a drop of hydraulic fluid.

The system uses Teleflex hydraulic fluid. I bought a new quart to accomplish the bleeding. The latest fluid product is clear, but it is the same stuff as the old style amber fluid. I did not drain out the old fluid as it looked to be in fine shape. The fluid costs about $13/quart. After closing up the system I did get some spills from the helm pump after it sat in the hot sun all day. Fluid escaped from the top overflow and made a little mess. I guess you could use a syringe to remove any excess fluid in the pump before sealing.

Once the hydraulic system was sealed, I installed the new drag link arm and tie bar. For a drag link arm I ended up using a beautiful one from Mercury in lieu of a Yamaha OEM part. The Merc drag link arm had much more detailed engineering, including a spring-loaded connecting bolt and an articulating joint at the drag-link/steering-tang connection. It fit the motor perfectly, too.

(I must mention that both the Yamaha and the Mercury drag links were sent to me by website contributors, and I am most appreciative of their generosity. Of course, the Mercury part came from the kindness of LHG, while the Yamaha was the largess of Ron Stan.)

If you are replacing a cable steering installation you will already have the drag link.

LHG also donated a Tie-Bar, this one originally supplied by Boston Whaler in the 1980's. It was in new condition and fit perfectly with the Yamaha engines.

The end result of this conversion was a much cleaner steering installation. The side mount cylinder was only about $275. This is quite a savings over center-mount cylinders, and as mentioned above, there may be other advantages, too.

Al Campbell of Teleflex Customer Service was a great help in revealing all the tricks of the installation. I see why Teleflex is taking over the hydraulic steering and rigging business--they make great stuff and have good people.

jimh posted 07-21-2002 11:49 AM ET (US)     Profile for jimh  Send Email to jimh     
I forgot to mention this:

At the exit end of the tilt tube the actuator arm of the HC5370 passes through a Steersman Nut. This seals the tilt tube and keeps the grease inside, the water outside.

The Steersman nut ($27) fits the standard 7/8-inch tilt tube treads. It has a grease fitting to keep the steering well lubricated. Again I used Mercury 2-4-C grease.

The tilt tube of the Yamaha appears to be threaded the same (RH) on both ends and is 7/8th-inch diameter at both ends. I think the Mercury tilt tube may be different.

Because of the symmetry of the Yamaha tilt tube, I likely could have reversed the actuator to take advantage of its higher thrust in one direction versus the other. I mention this situation in the Reference article on bracket installation. See the illustations in:

I was in a bit of a rush when I began this installation and it was only after I had mounted the cylinder that I realized I could have reversed it without reversing the tilt tube! Perhaps I'll try this in the future and see if the results are an improvement.

At the moment there is some noticeable steering torque, but that's because the trim tab settings on the engines were changed over the winter when the lower units were resealed. I expect to be able to reduce the steering load with better trim tab settings.

Chap posted 07-22-2002 02:37 PM ET (US)     Profile for Chap  Send Email to Chap     
Very informative and appreciated, thank you.
I myself need some hydraulic steering, soon.
Jim, how did you determine the positioning of the tie bar so your engines run parallel? One of mine appears out of wack to my eyecrometer. I was told to unhook the free motor and run the boat on a calm day so it could find its sweetspot, adjust accordingly.
Haven't done that yet.
lhg posted 07-22-2002 03:20 PM ET (US)     Profile for lhg    
The tiebar hole centerlines should be the same as the engine mounting distance. Some people add 1/4" for a little engine "toe-in".
On most Whaler Outrages/Revenges with notched transoms, this is 29 3/4". On the Whaler Drives, it was 28".
Armstrong brackets use 27" as their standard, but actually any dimension can be ordered.
Chap posted 07-22-2002 03:38 PM ET (US)     Profile for Chap  Send Email to Chap     
That sounds simple enough. I'll have to do some measuring ASAP.
I appreciate the info and continue to move along the learning curve. Hope all are having a good summer.
peteinsf posted 07-23-2002 07:31 PM ET (US)     Profile for peteinsf    

Adding a 1/4" would make the gearcases point outward. Is that "toe-in" or "toe-out"?


jimh posted 07-24-2002 12:02 AM ET (US)     Profile for jimh  Send Email to jimh     
Making the tiebar slightly longer than the center-to-center dimension makes the engine thrust vectors point inward slightly.

Yes, it makes the front of the gearcases point outward, but it therefore makes the back of the gearcases point inward. So I guess that makes it "toe-in", eh?

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