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Wed Dec 17, 2008 3:18 pm

I'm wondering if its safe to replace the the nuts and bolts on my Syncro front end with stainless parts to prevent future corrosion.

I'm looking at this hardware:
Lower control Arm nut and bolt (was rusted badly)
3 bolts/nuts holding lower control arm to radius rod and ball joint housing
radius rod hardware
end link nuts and washers. (again, badly rusted)
upper control arm nut

I am looking at Stainless A-2 (18 - 8 ) which has a slightly lower tensile strength than Steel class 8.8. (700 vs. 800MPa).Is this suitable for use on this application?

Here is a good reference on the strength comparison:
http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx

Wed Dec 17, 2008 5:15 pm

Stainless A2-70 usually falls somewhere in between SAE (US) Grades 2-4 as far as strength is concerned and a A2-80 is slightly less strong than a SAE (US) Grade 5.

Size for size:
ISO (Metric) Grade 8.8 is the rough equivalent of SAE (US) Grade 5
ISO (Metric) Grade 10.9 is slightly stronger (in both yield and tensile strength) than SAE (US) Grade 8

As far as I know, all Vanagon front suspension bolts are ISO (Metric) Grade 10.9.

The point is that neither A2-70 or A2-80 are appropriate for a suspension bolt application. There are some (316 Stainless) A4-100 class bolts on the market that are the rough equivelant of ISO Grade 10.9s, but they are expensive. Look for Bumax brand fastners if you are interested.

Wed Dec 17, 2008 11:20 pm

short answer- no. I worked for a military contractor for awhile, and they are anal on their bolt strengths. Certainly not for use on a suspension part that takes a lot of beating.

Thu Dec 18, 2008 8:02 am

Thanks guys. theres my answer. I'll go with the steel grade 10.9 bolts.

Chris - your knowledge is an asset to the vanagon community.

Thu Dec 18, 2008 8:36 am

Which one will be stronger after three years of snow and salt? I would bet the stainless, you choice though. :wink:

Thu Dec 18, 2008 8:36 am

Yep, I was one of those military guys once. A private contractor decided to replace the bolts in a 1200 psi steam line on a Navy ship with cheaper bolts. Twenty minutes after light-off of the steam bolier, the bolts failed, releasing high pressure steam into the boiler room and scalding four innocent sailors to death. Try explaining the savings of a few bucks to the sailors' surviving families. It was a sad day.
:cry:
[quote="beatrich"]short answer- no. I worked for a military contractor for awhile, and they are anal on their bolt strengths. Certainly not for use on a suspension part that takes a lot of beating.[/quote]

Thu Dec 18, 2008 8:54 am

Another thought on stainless is that they tend to come loose. Loctite and/or double nutting is often required.

Thu Dec 18, 2008 8:55 am

Forget the stainless. Just get the 10.9 's and a can of anti-seize and coat them before they get installed.

Thu Dec 18, 2008 9:03 am

These bolts are harder to find than I thought, in either 10.9 steel or 316 Stainless.

Does anyone have a fastener vendor that I should try?

gotbolts.com is the closest I've found, they have a 10.9 steel M12x1.5x120 (ETKA calls for a M12x1.5x110). I think the 120mm would fit no problem.

https://www.gotbolts.com/index.jsp?path=product&am...N.961.960)

Also, do I have to worry about nut strength as well? It seems that nuts aren't always marked with a strength class. I have seen some marked 8.8. But at last on the site above they are mostly not listed.

Thu Dec 18, 2008 9:05 am

Don't forget all the steel bolts can be easily found zinc plated. 8)

Thu Dec 18, 2008 9:18 am

You could try Jamestown Distributors in Rhode Island for stainless, don't remember what grades they have.