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68 Cutlass Front Suspension Woes


Guest stuckym

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I recently purchased some front springs for my 1968 Cutlass. The springs were installed shortly thereafter (properly placed in the frame pocket and indexed). I have just recently gotten the final weight on the suspension (engine, trans, fenders, radiator, accessories, etc...). I have stock upper/lower control arms and the correct pinion installed for a 68.

What I have found is that the ride height of my Cutlass is 2 inches too high after all of these parts have gone on the car. According to the assembly manual a level line should be drawn from the lower control arm mounting point right thru the lower knuckle of the pinion at the lower ball joint. I'm 2" higher than that and the front end is much higher than the rear.

The supplier of the springs has indicated that there is only one spring height for the car. At the time of the order I requested heavy duty springs for a 1968 Oldsmobile Cutlass with ps, pb, and no A/C. The springs that were shipped were: 1964-72 Cutlass 442 SU3785T Front Coil Heavy Duty. These springs have 10 coils and stand 15.75 inches (sitting on the floor off of the car)

What I'm looking for is a possible reason why the car is too high. Something is not clearly not right in my front suspension and I guess I've got to figure it out somehow. Maybe cutting down the springs will work but that still wont explain why stock components wont work with the car.

Does anyone have any ideas what my problem might be?

PS: I should add that anything is up for grabs as the cause. Even though I believe that the control arms and pinions are stock, I purchased the car with these components on it so maybe they too could be the problem.

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Edited by stuckym (see edit history)
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When the front suspension bolts were re-torqued after installing the new springs, was the car up on jackstands with the suspension hanging down? The weight of the car must be on the wheels when the suspension bolts are torqued. If not, the rubber bushings will be locked down with the suspension at full droop and the rubber in the bushings acts as torsional springs that increase the spring rate and cause the car to sit higher. This is a problem that comes up frequently in front end rebuilds.

Failing that, you need shorter springs.

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Wow... that had not occurred to me. The car was indeed on jack stands at the time that the bolts were torqued. I will give that a try. Thanks Joe!!

And... thanks for the quick reply too!

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When the front suspension bolts were re-torqued after installing the new springs, was the car up on jackstands with the suspension hanging down? The weight of the car must be on the wheels when the suspension bolts are torqued. If not, the rubber bushings will be locked down with the suspension at full droop and the rubber in the bushings acts as torsional springs that increase the spring rate and cause the car to sit higher. This is a problem that comes up frequently in front end rebuilds.

Failing that, you need shorter springs.

Hey Joe, If people wan't to get even more radical have someone torque the upper/lower arms with the car in the air with polygraphite bushings!!

Don

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Don,

Should we ask how you know this? ;)

I've been in the automotive business for over forty years and seen some funny things especially when people don't read service manuals or directions.

Sometimes it makes you wonder why your doing things when you get a phone call from someone who wants to know why a recall that you worked on isn't working or can't be installed. When you ask did you read the instructions?? Well you know the answer you get. I call it the long pause...........on the other end of the line......hello hello anyone there?

Don

Edited by helfen (see edit history)
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  • 2 weeks later...

So... as it turns out the suspension was not torqued when the car was on jack stands. However, it was torqued before the engine/trans/fenders/radiator/bumper/hood were installed. I figured that this might also lead to a higher than normal ride height.

After loosening the control arms and bouncing the car, I find that the suspension settled about a 1/2 inch but not nearly the full 2 inches that the car was high.

Joe mentioned that if this did not work, shorter springs would be required. I'm willing to try that but suppliers that I have contacted are indicating that there is only one size spring. What could make my car sit higher with the stock springs than it should?

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However, it was torqued before the engine/trans/fenders/radiator/bumper/hood were installed. I figured that this might also lead to a higher than normal ride height.

Yes it will.

After loosening the control arms and bouncing the car, I find that the suspension settled about a 1/2 inch but not nearly the full 2 inches that the car was high.

Joe mentioned that if this did not work, shorter springs would be required. I'm willing to try that but suppliers that I have contacted are indicating that there is only one size spring. What could make my car sit higher with the stock springs than it should?

If the upper ends of the springs are not properly seated in the spring pockets in the frame, the suspension will sit high. The spring pocket has a cylindrical feature that is supposed to sit inside the upper coil (the ground flat coil should be up on the spring). This part of the installation is blind and it's not hard to get the end of the spring stuck on that cylindrical locator instead of slipping over it. The good news is that if you remove the shocks, an internal spring compressor should allow you to get the upper end of the spring properly located without taking the front suspension apart.

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