. im willing to bet its lowered. maybe some others can chime in with possible causes.
Can C5 springs settle.....
Thread Starter
Instructor
Joined: May 2010
Posts: 179
Likes: 4
From: Little Compton, RI
Can C5 springs settle.....
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
All thoughts appreciated
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
All thoughts appreciated
Thread Starter
Instructor
Joined: May 2010
Posts: 179
Likes: 4
From: Little Compton, RI
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.
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.
Thread Starter
Instructor
Joined: May 2010
Posts: 179
Likes: 4
From: Little Compton, RI
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.
I'm an ex auto mechanic and although 60yrs, everthing looks as i would expect, not squashed bushings, spring mounts look normal etc.
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Safety Car
Joined: Jun 2009
Posts: 4,738
Likes: 15
From: OC Calif
St. Jude Donor '10
front 27.5; Rear 28-3/4. Looks like you're about normal. Springs usually don't fade, but rubber does.
The rears have rubber bushings on top of bolt and under at nut.
Fronts have rubber bushing under the adjusting bolts, and they do 'mush' after a while. When I removed mine, the right front was smashed in half.
So, I'd say you're not lowered, but basic rubber aging
Melting Slicks
Joined: Jul 2007
Posts: 2,939
Likes: 7
From: Simpsonville SC
St. Jude Donor '09-'10
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!
Melting Slicks
Joined: Jan 2007
Posts: 2,170
Likes: 6
From: Oilerville Edmonton
St. Jude Donor '08
edit: this is on my 00 with 54k miles
Thread Starter
Instructor
Joined: May 2010
Posts: 179
Likes: 4
From: Little Compton, RI
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??
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??
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
Most lowered cars end up with almost no space in the front and the nut almost right at the end of the bolt in the rear.
I'm not really sure what your problem is. It sounds pretty much stock to me. Does the ride height not suit? Does it not drive OK?
Do you have a fair bit more gap over the top of the wheels than in front of and behind the wheels?
Peter
I'm not really sure what your problem is. It sounds pretty much stock to me. Does the ride height not suit? Does it not drive OK?
Do you have a fair bit more gap over the top of the wheels than in front of and behind the wheels?
Peter
Thread Starter
Instructor
Joined: May 2010
Posts: 179
Likes: 4
From: Little Compton, RI
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.
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.
Melting Slicks
Joined: Nov 2006
Posts: 2,431
Likes: 3
From: Iowa City Iowa
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.
Thread Starter
Instructor
Joined: May 2010
Posts: 179
Likes: 4
From: Little Compton, RI
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.
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.
