dburgjohn

Does anyone make a replacement rear spring to help lower a C3? You can go only so far with the longer bolts. I sure would like another 1 to 2 inches but I don't want spring or bolts hitting tires or ground.

and yes I have looked at lots of ads for springs. none of them tell me what I want to know

C6DuffMan

Eaton makes springs in different heights. However, I bought a rear spring from them in stock height and needed to use 2" lowering bolts to level it out.

http://www.eatonsprings.com/index.html

TheSkunkWorks

If 8" bolts won't do the trick, you either have a highly arched spring or you're attempting to slam it far past lowered ride heights typically recommended for improved RR/AX performance. Curious; where are your Z and D heights now?

MIKE80

What are the recommended measurements?

chevymans 77

IF you are still running the stock steel spring bring it to a spring shop and have them take some arch out for you.

I had mine done twice until I got it the way I wanted.

The spring ends were to close to the wheels/tires so I had arch taken out so I could use short bolts and the spring end is now inside the wheel.

Neal

TheSkunkWorks

With full tank of fuel and driver's weight aboard, Z = 1" - 1.25", D = 1.25", by the "book". In addition, raising the diff and lowering the camber struts may be necessary to minimize rear-toe steer and improve camber gain, but doing so can change D math.

dburgjohn

I would love to do that, but no one here (or close) does it. I love so far out in the sticks the UPS has to bring the sun shine.

dburgjohn

I understand the drawing, but am not sure how to measure that with what I have on hand

TheSkunkWorks

Park on a level surface with the suspension settled and measure up to the CL's of the inner and outer camber strut bolts and subtract for the difference and you'll have your D height. Up front for Z height, you're looking for the difference in height from the ground to the bottom surface of the steering knuckle to that of the front, lower control arm CL's. Simple tape measure, or even a ruler will do.

The reason I always stress these particular dimensions over fender well or rocker heights is that non-OE tire sizes can substantially alter either of those latter specs.

gcusmano74

You will have to find 10 inch long bolts. I think that VB&P sold them at one time. I seem to remember they were supposed to be used on a C4. But a 9/16 grade 8 national fine thread bolt is what you probably need. A good industrial fastener house might have a couple for you, as well.

MIKE80

I recently measured mine, but I did it from the ground to the center fender wheel lip. My measurements from that are 26.5" front and 27.5" rear. I'll check using the method that you described. Thanks for the info.

69ttop

when I did my restoration I bought a replacment rear 9 leaf spring and installed it. I also found that the car sat up too high. so I too went through all the half *** stuff with the longer bolts which really didnt lower the car that much. I realized that the factory 9 leaf factory spring had 3 flat short top leafs and the new spring had 3 curved top leafs.
I exchanged the curved leafs with the 3 short flat leafs which made the car return to the factory ride hight with the factory 6 inch bolts.

dburgjohn

I have some 10 inch bolts, they get the bolts too close to the ground in the event of a flat and the spring too close to the wheel in the event of a curve

MIKE80

I had a set of 10" bolts, but went back to 8". When I was using them I cut 1" off and made them 9" and flipped the front bolts threads up.

MIKE80

I got 1" on both front and right rear, left rear was 1.25" following your measurements. I did not have anyone inside and only a 1/2 tank of gas. VBP performance plus suspension, 17x9.5 wheels, and 275/40 tires all around. To wheel lip from ground 26.5" both front, 27.5" left rear, and 27.25" right rear. Also measured from the ground to the inner and outer of both half shafts and got 10 3/8" for all readings, so they look nice and level.