john512

I have a '99 Coupe, 95K miles on it. I just got 2 new rear tires and immediately upon hitting the road/freeway I could tell something was not right. The car felt like it was rolling all over and around every corner if I pushed it a bit the rear slid out and AH came on. I let 2 of my "car" friends drive it and both say it is the shocks. My car bounces over even the smallest bump in the road. My thinking is they have been going for awhile and putting the car on the lift to get new tires was the final straw by stressing them further. Would that be a safe assumption?

If I do need new shocks, what would be a recommendation? I saw some threads mentioning the Bilstein HD and others mentioning the C6 Z06 shocks. Will those work on my car without any modifications? I don't have the Z51 package on mine currently.

Any advice would be most appreciated.

craig04c5

I have a base suspension coupe like you and I put new C6Z06 shocks on mine. They are very nice and less expensive than Bilsteins. They are a little firmer then stock but they absorb bumps and road imperfections much better.

Paul 75 L82

The C6Z06 shocks will fit your car. I just put a set on mine this past weekend. GM Parts House has great prices on them.

C5FORFUN2

Sounds more like low air pressure or softer sidewalls. Are the new tires the same size and type?

Bill Curlee

I have an 02 ZO6 and even with the Z suspension, I still had issues going around corners that were the least bit irregular. The car seemed like it wanted to skider off the side of the road. The car only had 50K on the shocks so I didn't think they could be bad.

Installed the C6 ZO6 shocks (direct bolt in replacement part) there was an instant reward on the very first highway entrance ramp. NO MORE bouncing off the road thru the turn!!!

There a great bang for the buck and an easy and affordable up grade..

BC

bighank

Heard some people complain that the C6 Z06 shocks and sway bars were a little harsh when driving. Put C5 Z06 shocks on and noticed immediate difference. Old shocks still seemed to have sufficient force as they extended fine and compressed OK too. New shocks are about 1/2" to 3/4" thicker and are a direct bolt on. Z51 sways and aluminium end links (ditch those plastic ones on your car) finished the upgrade.
Found then on Parts for sale. Try the shocks first then add the sway bars and metal end links. You won't be sorry.

imavettegirl

have you checked the air pressure in the new tires?

LoneStarFRC

Might double-check the lug nuts too. Wouldn't be the first time......

Luv2Fly

With almost 100,000 miles the shocks, whether they are the cause or not are worn out and worth replacing. I like the C6 Z06 I use now. I would definetly check lug nut torque and air pressures. it is not always the sharpest tool in the shed working at the tire centers if that is where you went.

john512

Not air pressure or lug nuts. Those were checked.
Has to be shocks. The car bounces over EVERYTHING.

Got 2011 C6 Z06 shocks on the way from Gene Culley.

Now I just need some place to install them. No, not doing it myself. I am retarded when it comes to working on cars.

Kale

c6z06 + lowered + base springs leads to some bad behavior while cornering and some jarring bumps.

But c6z06 shocks + z06 springs is pretty darn nice. It's a firm ride, but it's not bad.

KorbenDallas

It sounds like the main culprit is your plastic swaybar endlinks need replacing, and are most likely cracked.

But yes your shocks are worn and need replacing as well. Time for shocks/sways!

EDIT: Also a cracked leaf spring can cause your symptoms as well, but they rarely fail. Best to inspect the leaf spring in detail while doing shocks/sways. Inspect both top and bottom because the crack could be on the top of the spring. Good luck

John Shiels

at 95,000 miles your shocks were shot at least 60,000 miles ago! Bilstein Sports.

PEERPSI

While I agree based on the mileage your shocks are due for replacement I have to question if that's your biggest problem. You say you took the car in for new tires and noticed an immediate degradation in performance? How can that not be some how related to the tires? Tire design, grade of rubber or air pressure? What tires did you put on and are they the same size as what you took off?

slvr bulit

get the C6 Z51 sway bars and end links too!

imavettegirl

what is the air pressure?

do you have an accurate gauge?

who is doing the air pressure checking?

john512

Exact same tires the car has always had, the awesome Runcraps.
Same size, put on in right direction, tires were produced in January of this year, air pressure was 32 all the way around. Tires were the only thing done but I think putting the car on the lift caused something that was about to give way to totally give out. The tires would not explain the bouncing over ever little bump in the road, even the small lip going into my garage. If shocks aren't the culprit 100% I am sure it still needs them after 95,000 miles. When I get them put on I'll have the rest of it checked out. Just not taking it back to Goodyear (who did the tires) to check. Got a reputable Mustang shop 1/2 from my house recommended by a friend so I'll give that a shot.

imavettegirl

i believe 30 is the recommended pressure for all four tires.

try 3 different gauges.

you will see variation in them.

try to find a calibrated one.

i will bet $1 that this is the problem.

john512

Also, the TPMS in the car was reading the same tire pressures as the gauges I used.....

KorbenDallas

john512 don't waste your time with tire pressures, it's obvious that's not the problem. Check the lug torque since it's quick, but that's probably not the problem either.

Shocks normally have a gradual degradation, while the plastic swaybar endlinks on your model year have been known to fail out of the blue. How did the tire shop jack up the car? If they supported the car by the leaf spring then you probably have a broken spring.

This isn't going to be a "quick fix". My money is on the swaybar endlinks. When I upgraded to c5z06 swaybars in my 1999, one of the plastic OEM endlinks had a crack halfway through it. Others here have reported a full failures as well. So back to my original suggestion... get shocks/sways and inspect the leaf spring while you're at it.