blnvette

I installed a new TRW 355 pound spring on my 73 about a month ago and now it looks like a 4-wheeler. I had a vbs in the car and it cracked when I jacked up the front end so I had to replace it. I talked to the tech at the place I got it from, and he told me that they don't have any problems with the ride height being to high, with there springs. He says my toe in must be off, and that I need a alighnment. So yesterday I remove all the trailing arm shims and take it down he block and back to see if it will settle down. It doesn't go down one bit. I have 8 inch bolts and they are adjusted all the way down. I can take the spring loose, and the rear end will bottom on the rubber stops. I can adjust the camber and it makes no differance. Any ideas?
Spring pictures were taken after trailing arm shims had been removed and camber adjustments had been played with so it is off.

69autoXr

The tech is full of it in more ways than one. I'll give him the benefit of the doubt that he may not be fully aware, but TRW springs are notorious for producing ride heights that are too high. What I won't give him the benefit of the doubt on is suggesting that the toe adjustment would bring it down.

You'll either need longer bolts, or a VBP spring which are much flatter.

justaguy10825

Wouldn’t cranking down those spring bolts flatten out (pre-load) the springs & make it sit closer to the ground?

justaguy10825

I have not done it before... Mine is still apart until I can get some time to re-install the rear diff. So I am probably way off base right?????

pws69

No, "Tightening" the nuts makes the car sit higher.

justaguy10825

thanks!

gbvette62

Don't believe that tech, this is a common problem with new springs, not always, but often enough. This will even happed when rebuilding originals. Usually, they will settle down after a few hundred miles. I try to worn customers about this ahead of time. If they don't settle or you don't want to wait, 10" bolts are available to give you more adjustment. I'm not a big fan of the fiberglass springs, the 81-82 GM seem to hold up well, but I know that alot of the aftermarket ones have been known to crack or splinter.

blnvette

The ride height needs to come down allmost 2 inches, what supplier has a good spring that will solve this problem with the 8 inch bolts. I have bilstein sport shocks on it, so the spring will have to work with the shocks. With the 10 inch bolts I think the spring may bottom out on the road.

LFZ

oh no..the dreaded TRW rear spring!! ask around the forum, they are known to sit up really high..even with longer bolts.

Kid Vette

Welcome to the wonderful world of TRW design springs manufactured by Muskegon Brakes! Actually, I should say manufactured for Muskegon Brakes. That's the problem; they have somebody else manufacture them that is clueless about springs. And the techs at Muskegon Brake will only blow you a bunch of BS rather than acknowledge the real problem - their springs are manufactured with too much arch.

I tried 2 springs from Muskegon with the same results - my Vette was about 3" too high in the back. I now have a VBP spring and the height is perfect with the 8" bolts provided with the spring. Best thing to do is take the spring off and return the POS, then install a spring from VBP.

By the way, I have toured VBP's plant in Florida. They manufacture their springs on site and use different molds for each application to keep the correct arch.

1Fordman

I had to get the 10" bolts for a C4 to get the rear end down with the TRW spring. It should settle after getting some miles on it and just maybe the 8" bolts will work again. I plan on cutting the 10" bolts shorter if the rear end settles more as they do hang a bit low.

blnvette

kid vette
You got it exactly rite about the place I bought it from. The tech told me they only have a problem with 1 in 200 cars. What pound spring did you install? I had a VBS But it cracked length wise look at the picture

vettfixr

I have an early TRW spring that was manufactured by TRW back in the day. I've had no problems with ride height. You can lower the rear by going with 10 inch bolts but be aware that if you are running 15 inch wheels and get a flat the bolts will hit the ground because they are longer than the bottom of the wheel. It's better to run a good spring with 8 inch bolts than a bad one with long bolts.

69autoXr

Composite springs are said not to settle over time.

I've had my VBP composite spring for almost ten years without a problem, I recommend giving them another chance.

Kid Vette

Believe me, it is way more than 1 in 200. Get your money back on the TRW design POS and get a VBP. By the way, TRW has nothing to do with those springs now. Muskegon Brake bought the rights to manufacture the spring and has outsourced it to a supplier that they will not divulge. If you tell VBP that your previous spring broke they may even give you a credit on a new spring.

I'm running a 300 lb spring. My car has been lightened substantially. Most C3s would use a 330.

You could give these guys a try as well. Don't know of anybody that has tried them yet but they have a good rep. Hyperco

bwellisley

i just replaced my suspension with "as originally equipped" with the leaf spring and i have a ride height that is too high. i even bought the 10" bolts and have them extended as far as possible and it is still too high. i don't mind the height look so much, but it is causing my half shafts to knock! i need help with fixing this...i'm out of ideas...thanks!

chuck d

Having the half shafts operating out of the horizontal plane can cause vibration as some speeds. Longer bolts wil lower the back of your car.

bwellisley

i already have the 10" bolts in...do they even make them longer? maybe i should just put weight in the spare tire holder...

blue427

I brought a Muskegon spring at least 10 yrs ago and it never settled,so what I did was remove 1 leaf so I got the ride height down.I have the f41 suspension with seven leaves.It handles perfectly with the 6 leaves.I started with the shortest leaf and worked my way up,the longest leaf without the holes did the trick.It still sits plenty high and if it ever sags I can put the leaf back in.It takes less than 45 minutes to do the job on your back so it's no biggie.

another-user

i was also under the impression that you tightened the bolts up to lower the ride height. seeing as thats not the case, im all kinds of screwed right now. ive got stock 15" rallies on the car right now and 8" bolts, and the rear end is still about 2" too tall (only driven it a couple hundred feet, but i doubt itll settle that much) as it sits right now, the bolt is about 3/4 of an inch below the rim, and a 10" would put it almost in the ground. the geometry of everything in the rear end is almost 100% parallel right now though.