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Author Topic:   Stainless steel hardware on Galvanized trailer
specktrout posted 02-06-2002 04:56 PM ET (US)   Profile for specktrout   Send Email to specktrout  
Many of the old bolts holding on the brackets for the rollers and bunks on my galvanized trailer have rusted. I am planning on replacing the worst of them. Would it be better to replace with stainless steel or just redo with glavanized hardware? I am concerned that there may be a reaction between two different metals which may damage the galvanization if I go with SS nuts and bolts. Any suggestions? The price difference is only a few $$.
kingfish posted 02-06-2002 05:03 PM ET (US)     Profile for kingfish  Send Email to kingfish     
I'm not a metallurgist, but I don't think there is a potential problem with stainless hardware. I know that that is what I have done with all the u-bolts for my galvanized roller brackets on my galvanized trailer, and at least in the first year there hasn't been a problem.


andygere posted 02-06-2002 05:26 PM ET (US)     Profile for andygere  Send Email to andygere     
Use the stainless. Galv bolts are useless because the plating wears off the threads which is where you need it the most.
flieman posted 02-06-2002 05:56 PM ET (US)     Profile for flieman  Send Email to flieman     
The only negative I have heard is they are not hardened bolts like the trailer came with, something you might want to watch on certain things like spring hangers axle bolts. Stainless tends to be brittle I am told, Just my thougths.
kamml posted 02-06-2002 08:22 PM ET (US)     Profile for kamml  Send Email to kamml     
Back in my nuclear plant days we used steel galvanized pipe supports with a thin stainless steel shim when the supports were used to carry stainless process pipe. The purpose of course was to protect the stainless line. I don't remember now entirely why, it was either the galvanic corrosion problem or the stress corrosion cracking as a result of the surface contamination sensitization from the softer galvanized metal embedding in the grain structure of the SS piping base materials or maybe even both. At any rate it was important to protect the SS from the galvanized steel. That is not a problem on trailers. I plan on replacing some of my galvanized hardware with SS this year. Now you know for sure what I don't know anymore. Ken
Tom W Clark posted 02-07-2002 12:17 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I'm not sure if you're talking about replacing a few bolts or every bolt, but the difference in price is not going to be a few dollars.

I replaced all the nuts and bolts on the Calkins galvanized trailer under my 18' Outrage. These bolts, like those on almost all trailers, were grade 5 bolts. Do not use Standard grade or even grade 2 bolts. Galvanized bolts are standard grade. Stainless steel (type 316 or 18-8) is about as hard as grade 5 and thus is an acceptable substitute. However, It will cost about twice what zinc plated grade 5 hardware will cost.

In the case of my trailer, I spent about $50 to replace every nut and bolt on it. The stainless would have cost about $100. Your call.

SuburbanBoy posted 02-07-2002 12:39 AM ET (US)     Profile for SuburbanBoy  Send Email to SuburbanBoy     
I have used many stainless fastners, primarly purchased from West Marine. I will occasionally have stainless bolts sieze to stainless nuts when assembled. I believe that I should have lubricated the assembly with anti-sieze compound. This would have helped to reduce the galling I experienced in my stainless on stainless fastners. It was tough cutting my motor mount bolts off with my Dremel Moto Tool cutoff wheel.


andygere posted 02-07-2002 12:52 AM ET (US)     Profile for andygere  Send Email to andygere     
If you are going to replace a lot of bolts with stainless, it will be worth the time to go through a commerical hardware firm. You can find them in the yellow pages. West's prices on this stuff are pretty high.
Tom W Clark posted 02-07-2002 12:58 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
"ditto" to what Andy said. I bought mine through Tacoma Screw Products ( on my contractor's account. West Marine is NOT the place to buy this stuff unless it's a bolt or two.
peteinsf posted 01-14-2003 03:24 PM ET (US)     Profile for peteinsf    
It looks like am about to undertake the same project with my Calkins as Tom. As far as stainless, where can you get those square u-bolts?
kingfish posted 01-14-2003 03:40 PM ET (US)     Profile for kingfish  Send Email to kingfish     
Champion Trailers is a good source for quite a number of trailer-related things; I've ordered a fair amount of stainless hardware from them and been happy with it.


lhg posted 01-14-2003 04:42 PM ET (US)     Profile for lhg    
On my Outrage 25 trailer, every single bolt, washer and locknut that I could find in SS has been replaced, including the recent addition of SS axle bolts. It's the only way to go if saltwater launching is done. There are a few sizes of U-bolts, both round and square, that I have not been able to find, but even on those I use SS washers and nuts.
My main frame is all welded, so the biggest expenditure was for the roller bolts.
triblet posted 01-14-2003 04:53 PM ET (US)     Profile for triblet  Send Email to triblet     
In many cases, you can substitute a galvanized
piece with two holes and two SS bolts for a
U bolts. I did this recently when I replaced
the pieces that hold the end of the bunks.

I couldn't find U bolts the right size. Yes,
I tried Champion.

I've been gradually replacing the bolts on
the trailer. If I tank an old bolt off for
some reason, SS goes back. I'm probably half
way through.


weekendwarrior posted 01-14-2003 07:36 PM ET (US)     Profile for weekendwarrior  Send Email to weekendwarrior     
I recently refurbed my trailer (all new nuts + bolts, new axle and springs, etc..) and I asked about stainless hardware and was told by the local trailer shop that it's not used because it's brittle. Instead of flexing under load it will snap. I took their word and I used galvanized instead.

If you do use SS then please let us know how it turns out, I would like to use SS next time around if it's OK to use!

Tom W Clark posted 01-14-2003 11:44 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

The information you were given is bunk. Many trailer manufacturers use stainless steel standard or as an option.


McMaster-Carr has stainless steel (18-8) square U-bolts but they do not have them in the 3" size I think you are looking for. They have them in 2", 4" and 6" widths in a variety of lengths.

I think Iíve seen some at Tacoma Screw Products. Let me know exactly what you need and I can go look for you.

lhg posted 01-15-2003 02:20 PM ET (US)     Profile for lhg    
I have done what Triblet is doing, replaced them as the old ones rusted. My trailer manufacturer also offers an SS bolt option.

SS bolts are completely strong enough for trailer stress loadings.

The great thing about them, besides having a trailer with no rust, is the ease of working with them for future adjustments and repairs. No knuckle busting work. If you use the nylock nuts in place of a conventional nut and lock washer, be sure to put a dab of grease inside the nut before installing, even in the 3/8" size. This will prevent galling, which only seems to happen in the larger sizes. Almost all trailer bolts are either 3/8 or 1/2 sizes, course thread, except for the spring shackle bolts, which are 9/16, fine thread.

Most boat trailers are made with 1/2" spring shackle bolts (where springs connect to the frame), a real cheap-out mistake in my opinion. Both of mine came that way, and I replaced them with the proper 9/16 size. The squeaks went away, as did shearing wear and tear on the bolts.

Ljurgo posted 01-15-2003 05:25 PM ET (US)     Profile for Ljurgo  Send Email to Ljurgo     
I recently purchased a new aluminum trailer with akk SS nuts and bolts. Not a problem.

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