When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm the second owner of a 2000, 25K mile C5 convertible with stock FE1 suspension. The 65 year old first owner insists that the car has never been lowered.
Per the GM manuals trim height inspection procedure (suspension 3-16), the car should measure 6.02" (153mm) for the J height and 6.22" (158mm) for the K height at the prescribed measurement points.
The car is lower, by just about 3/4", 18mm to be exact.
The height isnt an issue but I hought these composite springs couldnt settle??
I'm concerned because the FE1 is kinda soft anyway, ive just upgraded to C6Z51 bars and plan to do the C6Z06 shocks but now i am wondering if the springs themselves arent bad
the springs will not creep. if the car is actually lower, i would check to make sure the bushings for the spring bolts arent smashed. also check for delaminating in the spring.
Saber
Although I haven't pulled the bushings, did look at them and they appear to be fine but i dont have anything to measure them against.
the 18mm drop is perfectly even front and rear, and the car is dead level side to side. that why i questioned the springs setteling or creep as you say.
Yes, the tires are GY run flats 245/45/17 and 275/40/18 with 8000 mile on them. its a dead stock car with the exception of the C6Z51 bars and metal end links i just added.
I'm an ex auto mechanic and although 60yrs, everthing looks as i would expect, not squashed bushings, spring mounts look normal etc.
10 year old rubber spring bushings will have collapsed a little I'd think. Prob. wouldn't be apparent unless you viewed them side-by-side with a new one.
On my 99, my front spring had fatigued. It was lower that stock. I finally replaced both springs with Pfadt coil overs. No looking back now, I love this suspension!
Thanks for all the help, ideas and advice, its appreciated...
I just looked in the GM manual and it lists a specification for the front Spring Adjuster Bolt Gap of 2 to 24mm (this is the thread showing between the bottom of the springs washer and the top of the bushing) and in the rear, they call out a Rear Spring Stud Height (total length of bolt above the nut) of 22mm to 46mm. the only thing they dont state is "what is the factory" setting....
I just measured my car and I am at 14.5mm in the front and 40mm in the rear. I dont know what it is supposed to be??
Anyone have a stock height C5 Vert that can measure theirs or has anyone recorded what the stock gaps are supposed to be??
Thanks for all the thoughts....was away for the holiday...
The car is fine, i have no issues but I am trying to figure out if indeed the springs have sagged on the car. I'm upgrading the FE1 suspension slowly, the new C6Z51 bars are an amazing difference and I plan to do the c6Z06 shocks next.
My concern is if the FE1 springs are sagging should I upgrade them to C5Z51 springs or am I chasing a ghost .....
I tried the dealer but they can only recite whats in my manuals, they cant tell me what the front adjuster bolt gap or the rear stud height is set at from the factory.
Peter, I'm not sure why you'd consider changing the springs when you're ride height is right where it should be. Maybe I'd consider new bushing ( if they look visibly smashed) but not even sure I'd do that assuming they have their original shape.
My bushings are fine.....
Per the Y2K GM manuals trim height inspection procedure (suspension 3-16), the car should measure 6.02" (153mm) for the front J height and 6.22" (158mm) for the rear K height at the prescribed measurement points, 35" back of frt wheel and 31" in frt of rear wheel.
My car is 18mm lower than these stock heights stated in the manual, 135mm front, 140mm in the rear. It is an unlowered car so the only thing that can account for an 18mm drop is spring sag, again, all bushings look like new. maybe 1~2mm out of the bushings from age.
The car being lower is fine, i have no issue other than trying to find out why its lower. Its 2000 with 25k miles and I am trying to figure out if the springs are begining to sag with age. Spring sag is mentioned in the GM manual but not in detail.