Ride Height

[C2Dude]

Just installed newly rebuild trailing arms on my 66. Before I align her I want to improve her ride height. As she stands now Drivers Front: 26 3/8 ground to fender lip
Passenger Front: 25 5/8
Drivers Rear: 26 3/4
Passenger Rear: 25 3/4

I spun down the drivers side spring nut to the lowest point, just a few revolutions, that I can still insert a cotter pin. Did not change anything. Go with longer spring bolts?

 

[Tom Bryant]

I suspect that you might be looking at the wrong end of the car. If the right front spring is lower, loaded, then the left rear will be higher. Since changing the load on the left rear spring bolt didn't affect the measurements any, I'd look to the front. Check for anything obvious first like damage to control arms or springs that are visibly different. Even worn-out control arm bushings can cause one side to sit lower. Then isolate the front by jacking up the rear on the differential making sure it is centered. Remove the rear wheels and drop it down to approximate ride height. Then take your measurements on the front to see if the right is still lower than the left. If it is, look for a not properly seated left spring or spring spacers in the spring, a shock that doesn't have full travel in and out or anything else interfering with the operation of the suspension. You could always swap the springs side to side and re-check to see if the problem goes away or shifts to the other side. It might be time for a new pair of springs.

Tom

 

[C2Dude]

I suspect that you might be looking at the wrong end of the car. If the right front spring is lower, loaded, then the left rear will be higher. Since changing the load on the left rear spring bolt didn't affect the measurements any, I'd look to the front. Check for anything obvious first like damage to control arms or springs that are visibly different. Even worn-out control arm bushings can cause one side to sit lower. Then isolate the front by jacking up the rear on the differential making sure it is centered. Remove the rear wheels and drop it down to approximate ride height. Then take your measurements on the front to see if the right is still lower than the left. If it is, look for a not properly seated left spring or spring spacers in the spring, a shock that doesn't have full travel in and out or anything else interfering with the operation of the suspension. You could always swap the springs side to side and re-check to see if the problem goes away or shifts to the other side. It might be time for a new pair of springs.

Tom

Thanks for reaching out, Tom. I have owned her since 2018 and done quite a bit of R&R. My novice assessment was that the front coils were fairly new from the previous owner, nice shiny black coils. I have not confirmed they are seated properly. As mentioned in the attached piece I plan to pull the wheels today and attempt to visualize the bottom of the coil's positions. A corvette forum member mentioned that the coils need to be indexed to the UCA and not the LCA. Regardless I did some analysis again in the attached piece which may or may not be correct, so I was looking for feedback. Thanks again Tom

 

[Tom Bryant]

1/8' is within tolerance and it would be hard to correct for that small amount. Do a visual inspection of the body mount cushions. I had one lower half by the rear wheel on my wife's 81 deteriorate when it was only about 10 years old. All of the rest looked new. Today, that one and all of the originals still look new. Also see if you can tell how many shims, if any were used on the driver's side. Also take a look at the rear differential crossmember cushions. You may end up shimming the body to correct the measurement to the ground. You would need to remove driver's side and put them in the passenger side, if there are shims in the driver's side and dependent on tire clearance. If the front tires are close just adding to the passenger side might get it close to an equal measurement. I don't think it would take 1/2" of shims because as you raise the passenger side weight shifts to the driver's side.

Tom

 

[C2Dude]

OK Tom, I will look at that. Thanks for taking the time with me.

 

[Tom Bryant]

No problem. I'm always glad to help, if I can. Let me know what you find.

Tom