Team Chevelle banner
  • Hey everyone! Enter your ride HERE to be a part JULY's Ride of the Month Challenge!
1 - 20 of 26 Posts

·
Registered
Joined
·
26 Posts
Discussion Starter · #1 ·
72 Chevelle hardtop coupe

I bought the car dismantled and I'm in the process of mounting the body to frame. The frame was mostly done when I got it but I'm just going over a few things before bolting down the body. Front and rear control arm bushings were replaced but the previous owner reassembled them using stainless steel bolts. Now I'm questioning if stainless bolts are strong enough. Is there any grading system for stainless steel bolts? I have a feeling the answer will be grade 8 bolts should've been used.
 

·
Premium Member
Joined
·
1,975 Posts
No engineer here, but stainless in general falls between grade 2 and grade 5 in strength. In my experience stainless hardware is fine in tension, but fares worse in shear compared to metals with higher carbon content. I would be less inclined to use stainless on suspension components.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #3 ·
Yeah I agree, I don't know why the guy used stainless. On such important bolts I would put back the original or get new grade 8 bolts. I may have the original bolts in a big box of bolts that came with the car. If I'm able to find them and they're in decent condition I can try to reuse them and get new locking prevailing torque nuts. Because the stainless nuts on there are not locking ones either so it's a bad situation. FYI I need 4 bolts for the front LCAs and 8 bolts for the rear lowers and uppers. I don't believe the front uppers have stainless holding the shaft to the frame but I will make sure later today.
 

·
Premium Member
Joined
·
343 Posts
I also believe places like UMI and BMR sell suspension bolt kits, which are fine thread grade 8 bolts with self locking nuts and all necessary washers. FYI
 

·
Premium Member
Joined
·
8,939 Posts
I have been on this planet for many years. I would not even THINK about using Stainless Fasteners on ANY suspension parts. ( On a showcar pushed into position and winched into the trailer, Never driven, OK )
All fasteners have a place in this world. Auto Mfg. want AND do build a car as cheap as possible. Todays High Tech or 50 years ago Low Tech.
All my suspension bolts are grade 8,, With Stover type lock nuts, I do NOT use Nylon lock nuts. To many reasons to list.
Trivia: I have Stainless Steel Muffler clamps & Hangers on my 70 Showcar. How to install Stainless Muffler clamps.
FIRST: Use an old style steel clamp to get the proper crush & indentations on your pipe. Remove the steel clamp & install the stainless, For LOOKS !
Try using a stainless muffler clamp to get the proper crush & indentations.
You get three guesses on what happens to the stainless clamp in this venture ! :surprise:
The first two answers ....... DONT COUNT !!!
Bob
 

·
Registered
Joined
·
2,424 Posts
....All my suspension bolts are grade 8,, With Stover type lock nuts, I do NOT use Nylon lock nuts. To many reasons to list.....Bob
I'm with this guy!

Stainless fasteners have no place in any application where high stress, forces and mission critical clamping reliability is required.

While there are stainless fasteners that are rated to grade 8, I would not trust or think of using them in engine, suspension or brake applications.

I will be using all fine thread ARP bolts for my front and rear suspension mountings and components.

Nylon lock nuts really don't "lock". They prevent the nut from spinning off but it will allow it to turn. Stovernuts (AKA prevailing torque nuts) are much harder to install and the torque needed to turn them before clamping needs to be added to your torque wrench readings. In grade 8, they are called G as they're specially hardened

Obtain and study the excellent book by Carroll Smith, Nuts, Bolts, Fasteners and Plumbing Handbook. It's an education.
 

·
Registered
Joined
·
3,697 Posts
I just use the regular bolts, lock nuts and regular nuts that came with the car.. If there rusty, I hit them with the wire wheel...
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #12 ·
So I found some of the original control arm bolts. Total is 9. 7 of them are correct size, 1 is a metric but extremely close in size even has the shoulder under head. Last one is a flange head but correct shoulder type bolt. While they aren't bad, I might just get some regular grade 8 bolts 1/2 × 3.5" length I think? This would be the 8 bolts for the rear control arms. Will there be a problem with the bolts not having that shoulder and reduced shank? Thought I read regular bolts were ok for the rear but that the Front lower arms needed to have the original shoulder type bolts.
 

·
Premium Member
Joined
·
8,939 Posts
Good parts aint cheap,,,,, Cheap parts aint good. Using wrong parts & pieces on your suspension may get you or " ME " :crying: a ride in a Hearse that has the correct suspension parts.
Bob
 

·
Vendor
Joined
·
1,485 Posts
So I found some of the original control arm bolts. Total is 9. 7 of them are correct size, 1 is a metric but extremely close in size even has the shoulder under head. Last one is a flange head but correct shoulder type bolt. While they aren't bad, I might just get some regular grade 8 bolts 1/2 × 3.5" length I think? This would be the 8 bolts for the rear control arms. Will there be a problem with the bolts not having that shoulder and reduced shank? Thought I read regular bolts were ok for the rear but that the Front lower arms needed to have the original shoulder type bolts.
The rear control arms grade 8 bolts in our kit are 4". Not sure if the 3.5" gets it or not just wanted to throw this out there so you can be 100% sure of fitment.:thumbsup:

Craig
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #15 ·
Good parts aint cheap,,,,, Cheap parts aint good. Using wrong parts & pieces on your suspension may get you or " ME " :crying: a ride in a Hearse that has the correct suspension parts.
Bob
Yes I agree, I wouldn't skimp on critical suspension parts. That's what got me here in the first place, everything was assembled when I got the car but I noticed the bolts were stainless and I became concerned. I'm pricing out the correct bolt sets to see where I can get a set for the front lower arms, and possibly the rears too.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #18 ·
When I do get the proper bolts, I'm thinking about how I can replace them. For the rear bolts I can take the weight off the rear and use a jack under the diff to find the spot where the bolt will slide out and put the new one in. One at a time of course.
It's the front lower arms I'm wondering about. Came up with an idea, someone please correct me if this is no good. I put the jack under the spring cup in control arm, this keeps spring compressed. Then put a jack stand under the bushing sleeve where I'm about to remove bolt from to prevent it from shifting down when bolt is removed. Also maybe I can use a punch or an old bolt to push out the stainless bolt and this would keep it aligned until I push the new bolt in from opposite side.
I hope this is possible without having to decompress the spring and drop the lower arms
 

·
Registered
Joined
·
3,697 Posts
When I do get the proper bolts, I'm thinking about how I can replace them. For the rear bolts I can take the weight off the rear and use a jack under the diff to find the spot where the bolt will slide out and put the new one in. One at a time of course.
It's the front lower arms I'm wondering about. Came up with an idea, someone please correct me if this is no good. I put the jack under the spring cup in control arm, this keeps spring compressed. Then put a jack stand under the bushing sleeve where I'm about to remove bolt from to prevent it from shifting down when bolt is removed. Also maybe I can use a punch or an old bolt to push out the stainless bolt and this would keep it aligned until I push the new bolt in from opposite side.
I hope this is possible without having to decompress the spring and drop the lower arms

That's what I'd do, should work just fine..
 
1 - 20 of 26 Posts
Top