theandies

'71 with VB&P 360lb composite spring (purchased from Van Steel).
Spring has been installed for probably 10 years or more. The other night I head what sounded like a loose washer rattling when I was aiming my headlights after my relay upgrade but didn't really think about it too much.
This morning when I got home from work I opened the garage door to move the Vette into it and saw what looked like a piece of plastic on the floor. After moving in I decided to inspect the spring because the first one I installed cracked (Van Steel replaced it since at the time it was almost brand new). That is when I noticed all 4 spring plate bolts loose and I would have lost one had it not been for the exhaust pipes. All 4 have lock washers.
My question is do you think heat from the exhaust and diff caused them to loosen? I have header wrap on the pipes to protect the spring for the heat. Also, I tried to tighten them and it appears the front bolts are bottoming out for some reason and I can't get the plate to snug up to the spring. The rear bolts will tighten fine since the holes are not blind holes.

Here is my plan and please suggest other options.
Get some SS flat washers for all 4 bolts so the plate will snug up. Not sure what is going on with that since it was fine on initial install 10 years ago. Apply some blue lock-tite to keep them from loosening again. I might even drill the bolt heads and safety wire them to keep this from happening again.

Anyone have the torque spec for the composite spring? I can't seem to find it. And I can't remember if you release the spring tension to tighten the bolts or do it with the wheels on the ground?
Thanks

revitup

There's got to be a reason the bolts won't snug up when they did before. Did you lose a spacer? I'd take the spring right off for a better look.
You final torque the bolts with weight on wheels.

DUB

Do as you wish...but if it was at my shop I would figure out how deep the front bolts can go and get then to be able to tighten up correctly. I am not a fan of adding washers due to I know how to cut a bolt correctly. I do not use loc-tite and never had in this area and I have never had a bolt come out.

I think what you saw after 10 years has got you spooked. But it only makes sense that IF the front bolts bottomed out...this was inevitable.

Call VB&P for the torque specs...or hunt for them on the website. I know many torque values off the top of my head but this is not one of them.

I tighten them when they are on the ground....I do this mainly for the steel springs that need to be compressed...and I do it for the composite ones also...but I honesty do not think that it matters due to you are not dealing with the arched leafs of a steel spring...and that thick block of a composite spring is not going to be an issue.

DUB

Les

Check the mounting plate for warpage. It doesn't take much to make that happen.

theandies

Thanks everyone. This is my daily driver and I work 12 hour nights. I woke up around 3:30 today to have a look so I didn't have much time. I posted this without really investigating too far. I just wanted some feedback from here. Thanks for all your suggestions.

I'll be looking at it more in the morning when I get home after work but when you work 12 hours it doesn't leave too much time between shifts (and I'm beat from work anyway).

Dub - After thinking about it on the drive in to work I agree. Something is not right about the front bolts and more investigation is needed. I'm not going to put washers on there but will change the lock washer out. I thought I'd just be able to tighten them up this afternoon but it more in-depth than that.

chevymans 77

I have the front set up on mine, just a few months back I noticed some black plastic on the floor under the front of my car so I put it on the lift and found the spring pivot cushions had fallen apart and fell to the floor leaving the bolts loose. A little more investigating and I found the end cushions were also crumbling along with the sway bar links. When the pivot cushions fall apart there will be slack in the plates at the mounting point.

I replaced all the urethane parts with new rubber parts, we'll see how long these last.

I ordered everything from VB&P but honestly most can be had from the local parts house except the spring pivot cushions, everything was fairly cheap just took a little while to get it from VB&P.

Neal

theandies

chevyman,
I think that may be my problem but I still haven't had the time to look closer.
Do you have a composite spring in the back too? If so are they mounted the same as far as the spacer goes?
I'm IMing Dan at Van Steel now to see if I can buy just the spacer setup as my spring is fine.

C3 Stroker

Specs from VBP are 70 ft-lbs., de-arch spring when tightening.

Info.....https://www.vbandp.com/instructions/...pecs/file.html

chevymans 77

I don't have the rear set up, just the front but I'm pretty sure they are mounted the same with the insulator pads between the mounting plates.

Looking at the instructions on the VB&P site the rear spring has the insulators.

Neal

DUB

BE CAREFUL...because if you tighten them more....it is HIGHLY possible that they can damage the actual rear end cover itself and cause for it to start leaking because when you tighten these bolts...they can crack the housing where the bolt is trying to go INSIDE your oil area of the differential. I HAVE seen this happen. So be aware!

I HONESTLY believe this torque spec is for a STEEL LEAF spring...which is entirely different than a composite spring.

DUB

Les

Gary at VB&P told me to torque his composite spring to 40 ft/lbs.

C3 Stroker

Yeah, looking at that number, it is high......I was checking from some general specs. The 40 ft-lb sounds better.....70 would squish that center plate on a composite.

theandies

Dub - Yes, I'll be careful.

I found my old install instructions and it is 63-77 composite kit 40-45Lbft.
It's also on their website:

https://www.vbandp.com/instructions/...pring-kit.html

DUB

I hope it all goes well for you when you get in there and begin to work on it.

DUB

theandies

I e-mailed VB&P to see if I can buy a new spacer but haven't heard back yet. I'm going to call them tomorrow.

In the mean time can someone that has easy access to their spring measure the thickness of the spacer? VB&P composite spring that is.

Is there any machinist here that can make me an aluminum spacer in case VB&P can't help me? I would think this may be a unusual request for them.

Dan at Van Steel said they no longer stock VB&P springs since they make their own now but he would have sent me a spacer if he had one laying around which he doesn't.

DUB

I honestly would not make the spacer out of aluminum. I feel that over time it could compromise the integrity of the composite and this you would be buying a new spring.

I feel that there still should be a material that can insulate the composite from any hard surface.

DUB

theandies

I was thinking the same thing. Just trying to come up with a viable solution.
Good hard rubber would be best but finding it is the hard part. My spring is good and I don't want to shell out $2 to $300 for a whole new spring.

DUB

Hopefully Vette Brake and Products will get back to you.

DUB

theandies

Dub, you wouldn't happen to have a car in the shop right now that has a VB&P spring on it? I need the thickness of the spacer. I've found you can buy hard rubber blocks on-line but need to know thickness then I can work from there.
Heading out to the garage now to investigate more and maybe I can extrapolate the approximate thickness from my current spacer.

Appears the dimensions are 7"x2"x7/8" thick. The thickness may be 1" because I'm missing some of it after looking at it real good this time. The spacer is definitely my problem.

DUB

I do not think I have one with a VB&P rear spring in it...BUT...I do have a factory spring out of a 1970...and I can measure the thickness of that spring where it contacts the rear end cover....and...I just replaced it with a new steel spring and I KNOW that the new spring was actually thicker....and I had to go out and buy new bolts to hold it to the rear end cover.

I will give you those measurements tomorrow...so having it be a specific thickness does not really matter due to the new reproduction springs are thicker.

DUB