Rear Ride Height Issue - Need Help

jguay75 · #1 (**permalink**) 08-12-2020, 12:53 PM

I have had a significant ride hieght issue discrepancy between the rear left and right. The shop has currently replaced the all four shocks, so all suspension measurements are within 1/2 to 3/4 inch (upper shold bolt to ground and lower shock bolt to ground on both sides). The attached pictures are after this was done.

The mechanic thinks that the body might haver flexed. But I don't necessarily think that is the case as there is no cracks or deformities in the fiberglass.

Anyone have ideas of what the problem could be?

eschaider · #2 (**permalink**) 08-12-2020, 01:35 PM

Well for one thing your rear tires are not the same size! Look at the measuring tape in your photos.

IRS or stick axle?

Ed

strictlypersonl · #3 (**permalink**) 08-12-2020, 02:34 PM

What is the measurement ground to frame, right in front of the rear tire, at each side?

DanEC · #4 (**permalink**) 08-12-2020, 05:01 PM

What kind of car and what rear suspension (Jag?)? Some of these replica chassis' are pretty stiff and with a pretty much 50/50 weight distribution - if you have a soft spring or short shock at the front it can transfer to the opposing rear and cause it to sit higher. You may need to start from scratch and adjust the coils on both front and rear.

cycleguy55 · #5 (**permalink**) 08-12-2020, 10:26 PM

Quote:

Originally Posted by strictlypersonl

What is the measurement ground to frame, right in front of the rear tire, at each side?

Agree. Frame measurements are the starting point. If they're equal and wheel opening heights are different then the issue is with the body or body mounting. More likely they're not equal and the springs need adjusting - either front or rear, or perhaps both. Corner weighting scales would be invaluable if available.

jguay75 · #6 (**permalink**) 08-13-2020, 12:20 AM

Here are the measurments from the frame to the body.

DanEC · #7 (**permalink**) 08-13-2020, 06:55 AM

Well, something is off there - wherever those are taken.

joyridin' · #8 (**permalink**) 08-13-2020, 08:45 AM

Frame to ground on a flat surface is the same for both sides? What is the brand of the car?

jguay75 · #9 (**permalink**) 08-13-2020, 11:45 AM

Quote:

Originally Posted by DanEC

What kind of car and what rear suspension (Jag?)? Some of these replica chassis' are pretty stiff and with a pretty much 50/50 weight distribution - if you have a soft spring or short shock at the front it can transfer to the opposing rear and cause it to sit higher. You may need to start from scratch and adjust the coils on both front and rear.

The car was made by NAF in '89.

Solid axel 8.8 by Ford. The suspension is technically a mustang/2 suspension. Rear is a 4 link. The ground to frame is 9 inches on sides of the rear and the front frame is 8 inches on both sides.

The car has never been wrecked and has been in our family since new.

cycleguy55 · #10 (**permalink**) 08-13-2020, 12:30 PM

So frame measurements are equal, yet wheel opening heights are different. The issue appears to be with the body or body mounting. I'd also check whether the top of the wheel opening is the same height from the top of the fender / body, as it could just be molded that way.

Is this something you can live with, or are you committed to resolving the issue?

t walgamuth · #11 (**permalink**) 08-13-2020, 01:15 PM

It sounds like something that can be lived with and would cost a lot to resolve what is in the end a cosmetic issue?

I'm thinking the owner would be the only person who would ever see it.

rads42 · #12 (**permalink**) 08-13-2020, 02:03 PM

Obviously everyone's tolerance for overlooking a cosmetic issue is different, but I can tell you for sure I wouldn't be able to look at that high side for very long if it was my car. That would drive me to either fix it or sell it.

FredG · #13 (**permalink**) 08-13-2020, 02:07 PM

I love a good challenge. You say the frame to ground measurements are the same on both sides. Are the measurements taken right in front of the rear wheels. I would pull both rear wheels, put jack stands under the axle and start inspecting the frame to body and frame to axle connections. With that big a gap, something should jump out at you as being out of whack. Did this problem appear after the shocks were changed? If so, take the rear ones off and see what happens.

Fred

t walgamuth · #14 (**permalink**) 08-13-2020, 02:45 PM

Quote:

Originally Posted by jguay75

Here are the measurments from the frame to the body.

At what point is the measurement being taken please?

Grubby · #15 (**permalink**) 08-13-2020, 02:51 PM

Measure frame to the ground. That is how the OEM service manuals do it. Body panels can have mounting differences.

John

vntgspd · #16 (**permalink**) 08-13-2020, 03:57 PM

I agree with getting solid frame measurements.

Can you clarify the replacement of the 4 "shocks"? Are they coilovers (shock/spring as one) or are the shocks separate from the springs?

If coilovers, can you measure the spring length between the upper and lower spring seat for each shock absorber?

Also, you noted in your first post that the shock mounting bolts are within 1/2"-3/4" of each other when measured to the ground. If the ground is flat, that is actually a large difference. That difference when measured 12-24" away from the shock at the fenders edge will actually increase. 1/2" at the shock mount could easily look like 1" or more at the fender.