PDA

View Full Version : Why did my new suspension lower my Cutlass?



Cobbler Bob
02-19-2025, 05:38 PM
216351
I have a 1971 Oldsmobile Cutlass S that over the last few weeks, I replaced the front suspension and now the front end sits significantly lower, and I cannot for the life of me understand why. Top is before, bottom is after. I re-used the stock lower control arms, but installed new Energy Suspension polyurethane bushings and ProForged ball joints. I re-used the stock spindles. I even re-used the EXACT same coil springs (I just sanded off the surface rust and painted them). I used Summit Racing tubular upper control arms and ProForged 1/2” tall upper ball joints. I installed a UMI bump steer kit too. QA1 Stocker Star single adjustable shocks were installed. Lastly, I put in the CPP high clearance 1-1/4” sway bar and UMI frame brace kit. The tires are 285/40R18 front and rear on 18x9.5 wheels with 5.75” backspacing (I did not change anything with the wheels or tires). The only other changes from the before (top) to after (bottom) photos is I took out a heavy subwoofer box that held two 12’s. Please explain to me how the front end dropped over an inch, even though I’m using the SAME springs and LCAs? Others on FB said it’s because I installed the tubular UCAs, but I don’t see how they or the tall ball joints can affect ride height.

boss_hoss
02-19-2025, 08:18 PM
Could be one of two things. The springs could be clocked differently, or when they were installed the first time they were partially sitting on the lip inside the spring pocket that locates the spring. When I was swapping springs they go caught on that lip and it made about 1/2” of difference.

andrewb70
02-19-2025, 09:19 PM
Could be one of two things. The springs could be clocked differently, or when they were installed the first time they were partially sitting on the lip inside the spring pocket that locates the spring. When I was swapping springs they go caught on that lip and it made about 1/2” of difference.

This sounds like a very plausible explanation.

Andrew

2ABodies1FBody
02-20-2025, 04:14 AM
I was under the understanding that taller lower ball joints lower the ride height. The way I think of it, let's say the lower control arm is in the exact same position as before, but the taller lower ball joint has now raised the spindle pin higher than it would have been with the original length ball joint. But I'm no expert.

Cobbler Bob
02-20-2025, 08:53 AM
Thank you Boss Hoss, I never considered that. I did make sure the spring was clocked right when I installed it, but I never looked at where they were when I removed them.

2ABodies - a few others said they thought it was the tubular uppers, but I still don’t see how. The upper ball joint is the tall one. The extra 1/2” space is between the spindle and the ball joint, which raises the outer end of the UCA up. Since the spring goes between the pocket in the LCA and the frame, I just don’t see how it could change ride height. I could be wrong, but I’d love to hear someone’s explanation. I think the above explanation of the spring clocking being off before I took it apart makes sense.

dhutton
02-20-2025, 12:35 PM
The old rubber control arm bushings can hold the car a little higher because they are in bind by design. Especially if the upper control arms were tightened with the wheels off the ground and not at ride height. The new ones have bushings that freely rotate so they have no effect on ride height.

ZZ430
02-20-2025, 02:36 PM
Have you driven the car yet with this configuration?

cdrod
02-21-2025, 05:02 AM
dhutton has a very good point. The factory assembly manual says to torque the control arm bushings with the full weight of the car on the suspension. Most DIY mechanics don't know to do this and torque the control arm bolts while the car is on jack stands with the suspension at full droop. It could be the previous parts where assembled incorrectly binding the rubber bushings and creating additional lift. The spring clocking suggestion is also spot on. Years ago I had the reverse situation, my suspension was higher after the rebuild, because springs were not clocked in the lower control arms properly. I was able to get back to the correct ride height once I rotated the springs to the correct position.

Rodney

Cobbler Bob
02-21-2025, 12:05 PM
I think you’re right! I definitely remember trying to articulate the upper arms after removing the spindles. I remember that they were all the way down in their relaxed position, and I was surprised how difficult they were to move up. I wasn’t able to move the UCA with one hand. Thank you! I went back to see the video and they’re all the way down unloaded.