I just put a TRW composite spring on my 69... It seems to sit really high. ( and it's the 315# version) It came with really long bolts, so I can adjust it down quite a bit, but don't think it will ever get the half-shafts horizontal...

What are your thoughts??

I did a complete rear end rebuild and thought I had a ride height problem when I first put the car down. I didn't have a composite springs but I did replace the orginal with a new steel one. Here is how I resolved my ride height issue. The ride height in the back was about 1.5 to 2 inches too tall. I first move the car around on the driveway. That helped a lot. When I first put it down the tires are still tucked in a bit. Then I added longer bolts 8 inch rather than the orginal 6 inch. Then re-adjusted the camber. Lastly drove it around the block with at least one good launch to transfer the weight to the rear. In the end I had to bring the springs up a bit on the long bolts to get what I needed. Hope this helps

There is nothing wrong with having your ride height up a bit if you like it that way. The halfshafts should not have more than a 3 degree angle at the u-joints for ideal operation. They can go up to 6 degrees, as long as they are within 3 degrees the opposite ends. Example, one joint at 3 degrees and the other at 6 degrees is okay. 1 degree and 5 degrees is not.

U joints do not rotate on both sides of the joint at an even rotational speed when they are at an angle. One side speeds up and slows down every 1/2 turn. You can see this by grabbing your socket set. Put a u-joint inbetween two extensions, bend it at an angle and rotate them. The greater the angle, the more the effect. The second joint in a shaft actually cancels the effect of the first one, and the total shaft output is a smooth rotation, if the joints are at the same angle. Exceeding 3 degree variation between joints will transmit an uneven output to the wheels. In our C3s raising the rear will usually change both u-joints in the shaft the same amount, and not create a problem.

Next if the height is too high or too low it will change the center of gravity and suspension angles. This will affect handling and change alignment. More than a couple of inches in the rear will also require resetting the FRONT alignment, it changes caster. Some height change can be compensated for with alignment, but the adjustments have their limits.

Just some back ground to think about. I prefer mine at OEM height for looks. Sometimes changing height (up or down) can accomplish a specfic purpose for handling, suspension tricks, drag racing, or different tires.

Ken Styer

My 71 is currently sitting about 2 inches too low all around.

I have a couple of questions as I still don't have my books!

1. what are the OEM stock length of the spring attachment/adjustment bolts at the hub end of the rear spring? I think mine are too long hence the 2inches low.

2. should my rear spring be dead flat (straight with no curve) under normal load?

My '78 has a TRW composite rear spring and the ride height appears normal. I don't know what spec spring it is, but it rides and handles fine.

Chips58 said: My 71 is currently sitting about 2 inches too low all around. I have a couple of questions as I still don't have my books! 1. what are the OEM stock length of the spring attachment/adjustment bolts at the hub end of the rear spring? I think mine are too long hence the 2inches low.

Answer: seven inches (178mm)

2. should my rear spring be dead flat (straight with no curve) under normal load?

Answer: absolutely NOT!
If the spring is flat with NO curve, it is BEAT. Replace it.

John

that's what I thought.... maybe time to put a composite spring in.

I'll measure the bolts as well, 'cause I think they are too long.

thanks John.

chrome bumpers on both ends rule....

Before doing anything drastic, give the spring a couple of weeks to settle. They could come down as much as a couple of inches on their own. Joe

I've heard that you can send your springs to Eaton Spring and they will rearch them, rebuild it and ship it back.

Any good spring shop can rearch steel springs. But it is a good idea to give them a few weeks to settle. Sometimes they change quite a bit.