Oldssupreme

I am rebuilding my suspension on my 72 supreme. Instead of buying a new set of control arm bolts for $90, can't I use grade 8 bolts of the same size from the local hardware store for much cheaper? The original control arm bolts have a slight "shoulder" to them that the hardware store bolts don't, but appear to have the same amount of thread and smooth areas.

kitfoxdave

which control arns? front or rear? If you do go down this path.... buy from a reputable supplier like fastenal... not all grade 8 maked bolts are grade 8... Check the tolerances on the shank... sometimes the reduced shank bolts have tight tolerances where they maie into holes in parts. If you reply quickly and they are the rear bolts, I'll check mine tomorrow for grade marks,,(putting the control arms back in...)

Oldssupreme

Kitfoxdave,
I am referring to all of the control arm bolts, front and rear, upper and lower. My rears appeared to have a larger head than the fronts, although the shank seemed to be the same size on both. I was in ACE Hardware yesterday and was looking at their grade 8 hardened steel bolts, but i didnt have my originals there to compare. I did note though, that the shoulders were a tiny bit wider than the rest of the shank on he originals, whereas the ACE Hardware bolts were the same diameter all the way down.

You said that not all grade 8 bolts that are marked as such actually are. How could i tell? I wouldnt want to get this whole car back together to realize that i put weak bolts in the control arms.

Octania

Absolutely you CAN use alternate fasteners. As long as the length and whatnot are similar, and the strength is adequate, you should be fine. Grade 8 is pretty beasty. You are aware that the nuts used are prevailing torque type, and not just "a" nut, right? I'd say "toplock nuts" as seen at:

http://en.wikipedia.org/wiki/Distorted_thread_locknut


With millions of those cars made, and thousands still being parted out in the western and southern USA, why would you need NEW ones at that price? Good used real GM parts are the next best thing to NOS GM parts. Better than reproduction.

Oldssupreme

Octania,
Thank you very much for the info. I was not aware that a special nut was used. I looked up your link, but i still have a question: would i be able to reuse my original nuts on a new ace hardware type grade 8 bolt?

I also liked you idea of purchasing a good used set, never thought of doing that. I figured everyones would be bad like mine. All but 3 of my bolts came out okay, i just figures newer bolts would be better than older.

So let me pose the question, does anyone have a complete set of control arm bolts and nuts, front and back, upper and lower for sale at a decent price?

MDchanic

I agree, scrounging used fasteners is fine if yours are trashed.
Definitely no need to spend crazy $$$ for new ones, which may or may not be as good as the originals.

The nuts are a variety of what we always called "airplane nuts" - they always have a bit of "grip" to them, so they won't just unscrew, even if they somehow loosen.
These particular nuts are all metal, as opposed to the other other kind of "airplane nut" ("Nyloc"), which have nylon inserts.

- Eric

70Post

Do you own a camera? What shape are your good ones in?? Inspect them for heavy pitting/rust.

Sounds like all you need is 3 but the lower rear control arm front bolts (the 2 that go through the frame) have a different head design.

New lock nuts are cheap to buy. If for some reason every place you shop there has ridiculous pricing on the locknuts then let me know.

Pics of typical locknuts below...

oldcutlass

Grade 8 bolts would be fine. The nuts need to be a gr8 Stover locknut (as pictured above), these can be found at a local fastener or bolt house. There are Fastenal stores all over the country.

MDchanic

Thanks for letting us know the name of those nuts - I never knew what to call them.

And, yes, Patton's picture has the exact ones.

- Eric

joe_padavano

I've used Grade 8 bolts and nylock locking nuts on control arms on several cars with no problems. Nylock nuts are the ones with nylon locking features as opposed to the distorted thread all-metal locknuts used by the factory.

kitfoxdave

Measured a few bolts today. They are not close tolerance shanks on the factory bolts. Get grade 8bolts from a good source. A lot of counterfiet ones out there. If they stretch under given torque spec throw them away. Factory bolts in good shape would be best.

Oldssupreme

Thanks for all the info. I put a post up in the wanted section for a clean used set and am talking to someone about purchasing. If that doesnt pan out then i'll look for new ones with the correct nuts as you all specified.

64Rocket

What was the outcome of you search for bolts ?
My experience with Fastenal" is the sell in bulk .
I always thought that the "all steel" nuts were called "crimp nuts".
Your best bet is the factory bolts. They have the shoulders on them to carry the load.
Check with "John" 2blu442, I'm sure he has hundreds of them.

Gene

Oldssupreme

I wound up buying a nice clean used set from 1001 coins. Solid set from a colorado car.
Thanks for all of your input!
Chris

Big red72

I bought the complete bolt kits for both upper and lowers at Fusick for about $55.