Stainless steel leaf spring trailer bolts?

tank1949

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I am doing some maintenance on my tri-ax. aluminum railed trailer. It is rated at 13500 lbs. I replaced leaf springs and replaced shackle bolts with 1/2" 304 SS bolts and lock nuts and proper sized leaf spring spacer for 1/2 bolts. Since my trailer will be used in salt water, I chose SS bolts. A local trailer shop indicated SS bolts would work fine, even though he only sells grade 8 or 10 steel bolts for leaf springs. Owner said that he didn't get much of a demand due his customers not wanting to spend the extra money on SS. It seems penny wise and pound fooling by not spending the extra on SS if you have a salt water application.

Recently, a friend warned me that grade 8 bolts would last longer since they are harder. However, salt water in not too friendly on these non-SS bolts.

I plan on transporting a 7000 lb boat on this trailer for over 1000 miles. Anyone had problems using 304 SS leaf spring bolts?
 

Scott Danforth

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304 sttainless is only as strong as a grade 2. I prefer galvanized or florokoted fasteners
 

Skypirate

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308 1/2 bolt shear strength is a little over 45000 psi or a little over 5000 lbp, tanden axle with rockers should be 14 bolts for suspention, so take trailer weight plus boat weight divided by 14 will give a very close guesstimation of the load per bolt
 

Skypirate

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Works out to be 500 lbs per bolt +/- ( taking into consideration tongue weight on tow vehicle)
 
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alldodge

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I would stick with at least grade 8 bolts over 304. Also keep in mind 304 will rust, just not as bad. I would rather have rusty bolts then chance it, and as Scott mentioned find galvanized grade 8 or 10
 

Scott Danforth

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not to mention stainless bolts are a one-time use, then the threads gall.

I run a 9/16" galvanized shackle kit on all the spring shackles. Proper shackle bolts will have a very short threaded section and a long shank once installed, I hit with a cold galvanizing spray to cover any tool marks. Then go boating - I dip in the brine all the time, Just lube the shackles periodically (like when you check the wheel bearings).

I have not opted for the greasable shackle bolts yet, as the cross-drilling weakens them. I do hit the shackles with a shot of LPS #3 or Red & Redi or even white lithium using a spray tube. I will soon be trying the LPS clear penetrating grease (its GRAS listed, so I figure better for the environment). I would rather have a bit of grease overspray on the shackle bolts vs a rusty shackle that squeaks.
 

Skypirate

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if you'd rather use titanium, :) I have a source, being a mechanical engineer has its advantages
 

Skypirate

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Once any bolt is galvanized it looses shear strength , on a 1/2" bolt it will have a shear strength of about 8000psi less then a non galvanized bolt of same composition, galvanizing softens the bolt, cyonide use to be used in the process ( old way) now the new way uses a man made equivelant to cyonide , can't remember off the top of my noggin
 

Bondo

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Ayuh,.... If ya use anything but steel bolts, it's Harder to take apart later,.....

With steel bolts, I just torch 'em off, 'n get new,....

SSteel the threads gall, 'n ya end up bustin' 'em off, with the ole pipe on a breaker-bar trick,....

Torches won't cut ssteel,....
 

tank1949

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Ayuh,.... If ya use anything but steel bolts, it's Harder to take apart later,.....

With steel bolts, I just torch 'em off, 'n get new,....

SSteel the threads gall, 'n ya end up bustin' 'em off, with the ole pipe on a breaker-bar trick,....

Torches won't cut ssteel,....

My 60 amp plazma cutter will.

"Fluid Film" is great stuff for steel.
 

krakatoa

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SS bolts looks nice but doesnt hold sttrenght you need to installa in your trailer galnanized bolts with lock nuts. Forget about SS. Bolts, they are weak.
 
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