When I go over speed bumps the rear of my IROC just drops with no spring to it. Is that a sign that I need to replace my springs. I am confused because when I back up I can feel and see the back of the car bounce as if it has some spring to it. I have to replace the panhard bar, because the bushing is worn out. I just recently replaced my rear shock with Monroe, so I know I do not need shocks. What is anything am I missing? Thanks

Springs are dirt cheep, and you can change them yourself in like 5 minutes or less, especially if the shocks have just been replaced since the hardware won't be all rusted up.

Try it and see. I think it'll answer your question. Use the CC635 set.

nothing lasts forever, including springs, they weaken over time

good luck

UMM, if your car is bouncing and bottoming out I think your shocks are done
how long ago did you change them?
To check, push down on the rear of the car and try to bounce it. If it bounces around then you need to get warranty on your shocks
It should just rebound back to normal with no bouncing at all.
I'm not disputing that your springs might be shot cause pretty much all of them are but you shouldn't have any bouncing.

Thanks for all the replys about the springs. I guess I be getting new ones. I will keep you guys posted when I change them out. Will the CC635 set restore it back the the orginal ride height?

Apparently two types of springs were used in the rear, Moog CC635 (cargo coil) and 5665.

JamesC

I need to know which rear spring CC635 or 565 will restore it back to the orginal ride height? I have heard different stories on both set, just need a clear answer from someone that have replaced them.

As far as I know, both are stock replacement springs. I'm planning on using the 5665's.

JamesC

Thanks, then it's settled 5665's it is. Thanks JamesC

JamesC,

When do you plan on getting your rear springs? Where are you going to buy them from?

i'll sell you a set out of an 89 iroc Z28 for 50.00 shipped from bakersfield, ca. email ron09517@aol.com

I'm buying Spohn's IROC-style replacement springs in the next week or so (along with his tubular arms, Koni Reds, and strut mounts).

JamesC

Use these pics as a reference. Check out my ride height, fender well clearance, etc. This is my car is it sits now with the STOCK RIDE HEIGHT replacement IROC springs from spohn. As far as I know this is what thirdgens are supposed to look like, most have just sagged over the years because the springs get worn out.

I hit speedbumps and driveways all over town and I never even scrape my air dam.

http://img168.imageshack.us/img168/5449/p1010005py6.jpg

http://img257.imageshack.us/img257/2386/p1010006wf1.jpg

http://img405.imageshack.us/img405/8642/p1010007gz2.jpg



JamesC - you're about to have the exact same setup as me. Koni reds, Spohn's IROC springs. I installed NAPA Chassis strut mounts too at the same time.

JamesC,

Did you every get you Spohn's IROC-style replacement springs yet? If so have you installed them yet? I brought the 5665 rear springs from Summit and I will be installing them this weekend. I will let everyone know how is goes.

I ended up purchasing the springs from CarQuest (and saved a few coins). The Konis just came in this afternoon. My goal is to install everything next week.

Hey, Dark,

Are you still running the Konis on the highest setting?

JamesC

I put Husky variable rate springs and since, even loaded the rear never tuches the ruber absorbers over the speed bumps.
It is now 4weeks and the rear is still 1" higher then the front unless the fuelthank and the trunk are full.
I also put 4tgen isolators but the old one would still have been fine.
It is also a great improvement for driving fast, the rear hops less around.

The fourthgen isolators may be responsible for the one inch that you mention.

JamesC

Im happy with it as it is and Im shure in 1-2 years it will come down that tiny inch, and with the full tank its perfect.

Before buying the springs and the isolators I did read some tgo treads about the isolators, and they stated the new ones 4tgen are 1" taller. But I compared them wen installig and there is no real difference maybe 1/2 inch and the conception, they were softer with holes. But in 16 years i really doubt they are going stay as tall as the old ones.
I bought the new ones because the way my rear end hopped and dropped was a real nightmair and was affraid that just changing springs wasent anough.

Changing the rear springs was the cheapest, quickest (3bolts) and efectivelyest upgrade I did on my trans am.

Hey, Dark,

Could you possibly measure from the ground to the lip of the rear wheel well for me. I'd like to see how close my measurement is to yours.

Thanks,

JamesC

Did you feel a different in the ride after you installed your rear springs?

Yes, I'm very pleased, though I haven't done the fronts yet.

JamesC

Good for you JamesC. I will be installing mines this weekend. I hope everything goes well. By the way what springs did you install? Did you run into any problems during your install that I should look out for? Thanks for all of your help.

No, the install is straightforward (you might consider taping the insulator to the springs for an easy time of it). The whole business--new ES end links, the news Konis and springs only took a couple of hours or so.

JamesC

I must say to everyone who help me trouble shoot this problem it is now fixed. I install my new springs this weeked and the only thing I can say is wow. The rear feels like brand new and I no longer bottom out when I go over speed bumps. It was just like you guys told me it would be all of a 15 minute install. I am sorry I waited so long to replace them. for all the advice.

JamesC,

Did you change your front springs yet? If so which front spring did you get and where did you get them from? Thanks

I used Moog 5662. I purchased them from CarQuest.

JamesC

my sport coupe looks sweet w/ the zr1's and the iroc springs, i absolutely love it. probably should look into getting rid of the gr-2s though...and maybe some 285's out back...

Um, guys....

For what it's worth:

It's a myth that springs wear out. They are pushed beyond their fatigue limit and then they change their mechanical properties, one of which is loss of spring rate. If you don't push them into resonance or overload them, they will generally settle into a set ride height, and stay there for life. I've had heavy duty KONIs on my car since 1990, and the WS6 springs have never sagged, even after 23 years. That's one of the reasons I've stuck with them all this time. The other is that they work so darned good on the autocross course that I can't bear to get rid of them!