I want my 90 Grand Prix to ride nice

[redmetrix]

I believe this is the 4th summer I have had my 90 Grand Prix. I've noticed beginning last summer that the ride seems a little harsh. I am pretty certain all the struts front and rear are the originals. The car currently has 117,000 miles on it. It does have FE3 with all stock components.

 

You know how some concrete highways have tons of little bumps that send a lot of input to the suspension? Well on this sort of highway I am getting a lot of input in to the car, it's as if the suspension is not moving as freely as it should. The ride can be very bumpy riding in the car on that sort of road surface.

[pitzel]

Pick yourself up a pair of KYB SR4026's for the rears, about $75-$85 a piece if you shop around (basically its a pre-assembled unit, so you get a new mount, etc., basically ready to go!). And make sure your leaf spring pads are still in place -- if not, then Moog K6544's or the thinner Dorman pads to replace them. The K6544's will even raise the back about 1cm, which helps alleviate the infamous sagging that these cars tend to have.

 

You'll seriously think that you got yourself a new car after you replace those rear struts!

 

With the fronts, you'll need to borrow/buy a special tool to remove them through the strut tower.

 

As for tools for the rears, you'll need a floor jack (not the jack from your trunk, but a proper shop floor jack), a pair of jack stands, some blocks for the front, penetrating oil/fluid, wrenches to remove the brake calipers, a 24mm deep socket (impact-rated if you got them), a 15mm socket, a small 5-8" piece of cut wood to help compress the spring, a hammer (soft hammer if possible), and a 1/2" torque wrench that can put 134 foot pounds on the strut to knuckle bolts. And potentially a few other tools and bolts if you have the dreaded auxiliary spring. A long 1/2" drive breaker bar will also be needed if you do not have impact tools. Take a look at your rear brake pads, if you need to do any work on them, you'll have it all wide open at the time so may as well order any needed parts and/or rent the tool to service them as well.

 

Oh and one more thing, you'll want some brake slider lube for when you put the calipers back on. The strut bolts are knurled/splined, so they have to be pounded out. There's a few Youtube videos on it, or just ask your questions here.

Edited July 20, 2014 by pitzel

[redmetrix]

I will probably just start with the rear struts.

 

What did GM change on these 1st Gen W's to make them ride different from one car to the next? For example to the best of my knowledge no matter if you have a base 90 GP with FE1 or an SE with FE3, they all got a 12 MM rear sway bar. So something else must be different, is it the spring, the struts or both?

Edited July 20, 2014 by redmetrix

[pitzel]

Can't answer your specific FE1 vs. FE3 questions any more than you already know suspension-wise. I do know that the FE3 configuration uses a different steering rack than FE1. Different gear ratio, for more responsiveness on the FE3 version. Probably could be back-fitted, although I don't know many who would go through the trouble of swap out a steering rack as a 'mod'.

[jman093]

Spring rates were different front and rear. FE3 obviously being higher. Front had a larger sway bar with FE3. I'm also not sure all FE1 cars had rear sway bars, but you're right that even FE3 cars only had that twig in the rear.

[pitzel]

Spring rates were different front and rear. FE3 obviously being higher. Front had a larger sway bar with FE3. I'm also not sure all FE1 cars had rear sway bars, but you're right that even FE3 cars only had that twig in the rear.

 

Yeah no rear sway bar in my FE1. Though I am in the process of adding one from a FE3 car.

[redmetrix]

Spring rates were different front and rear. FE3 obviously being higher. Front had a larger sway bar with FE3. I'm also not sure all FE1 cars had rear sway bars, but you're right that even FE3 cars only had that twig in the rear.

 

I've seen Regals, Luminas, and Cutlasses without a rear sway bar. Have yet to see a GP without a rear sway bar. Has anyone seen a GP without a rear bar? If so what year and trim was it?