CorvetteForum - Chevrolet Corvette Forum Discussion - C4 General Discussion

1986 vert jounce / rebound test fail

standswithabeer — Fri, 22 May 2026 05:14:06 GMT

hey guys, 1986 vert here.
according to the gm heritage center specs, I should be seeing 3.6inch jounce with 3.7inch rebound on each corner. my car has 75K miles, great mechanical condition overall. confirmed FJY front spring {various reports of 335 or 310lb/inch rate} w/Monroe OES Spectrum shocks, and NYR rear spring {233 lbs/inch rate} and unknown shocks. Possibly original, no lable, not leaking. suspension bushings look ok.

am only 158 lbs wet, and when I press down to obtain jounce/rebound readings I get almost nothin'. each corner may go down/back up about 1/2inch only. this doesn't match spec, am wondering if anyone has had similar results? nothing found during "search" here. suspension doesn't seem "stuck" when checked on a lift, as all wheels droop seemingly ok.

thx, bob p

New sneakers

Blu89C4 — Fri, 22 May 2026 03:13:32 GMT

Today the c4 got new sneakers. Toyo Extenza HP2s. Amazing the difference in the ride. Bought the car and never knew about the date code. Learned something new and realized they were 22 years old 😳.

1990 C4 RPM Instrument

altownsend — Fri, 22 May 2026 01:04:27 GMT

1990 C4 Base Model

I replaced a couple of parts after doing research on my non-functioning RPM gauge in the dash. It did not fix the problem. Will someone tell me how to fix my RPM gauge? Thanks

1990 C4 Base Model A/C not working

altownsend — Fri, 22 May 2026 00:57:34 GMT

1990 C4 Base Model A/C not working. All of a sudden, my A/C stopped working. From cold to A/C clutch not turning. I took the negative battery cable off to reset the A/C. Nope, did not work. I put my gage on, and the needle showing charge went to mid red.

So, what should I try next? I changed out the o=rings about 2 years ago, and everything was wonderful for all of this time. What additional testing should I do to get to a fix? Thanks

Rack causing steering issues?

Cruisinfanatic — Thu, 21 May 2026 23:03:30 GMT

My rack doesn't leak in my 85, but the car is all over the road even though the suspension looks fine and tires not too old.
Steers hard, but I can't compare to the way it was when new. It's been 41 years.
Could the rack be the cause of jumping all over the road at 70MPH?

1995 ZR1 correct paint on front bumper

vetteracerx — Thu, 21 May 2026 22:08:30 GMT

Can someone please give me exact detail about how the black is painted in the recesses for the marker lights and fog lights. My car is red. Thank you

87 Doug Nash reverse lock out issue

mystichrome — Thu, 21 May 2026 14:17:58 GMT

I recently changed the shift boot on my 87 to an aftermarket one - I had reused the ring that was stapled to the original boot and ziptied it from the inside to stay in place.
After putting it back on and reinstalling the shift ****, my shifter goes into reverse without needing to lift the lockout. I can physically move it but I'm not sure if something is just sitting higher and keeping it in lockout mode.

Before I take things apart and mess it up even more I wanted to get any info from someone. The last time I drove the car was fall of last year and it was working, then I changed the boot over the winter but never tried it until now.

Thanks everyone

Replacing Headlight Motor Gear and Bushings

edenrock69 — Wed, 20 May 2026 20:47:17 GMT

Hi Everyone, I have a 1996 C4 and in the process of replacing the gear and bushings on the passenger side headlight motor. The bushings have disintegrated hence the motor will not shut off. The problem I ran into is upon removing the motor from the headlight assembly and opening up the housing to get to the gear, I can't get the gear out of the housing. The gear is on the stem and moves freely but is stuck in the housing for some reason. I watched a video and the guy said to put a screw driver thru the hole on the stem and pull. I did but it won't pop loose. Note: On the drivers side there is an opening on the housing to get a screw driver in and push the gear/stem out using a hammer. The passenger side doesn't have this design. Any suggestions on how to remove the gear that is on the stem out of the motor housing? Thanks.

New to forums, new to c4 life.

Ajaes — Wed, 20 May 2026 19:47:14 GMT

Hey guys, I am new here and apologies if im not doing this correct but I got an 84 c4 corvette a year ago and I've been doing little things here and there to freshen her up. But, I was wondering if any of you have any advice on what I should tackle first. She runs and drives. I just took apart the headlight motor and fixed that so now I can drive it at night. But I was wanting to do a full interior fix but should I focus on things that keep it on the road first?

non ethanol gas

ssevin — Wed, 20 May 2026 15:59:35 GMT

Who here is running Non Ethanol gas if you can get it, in your C4?

85 Coming out of storage.

plaidside — Wed, 20 May 2026 00:48:07 GMT

i am going to help a friend who owns an 85 Vette that has been sitting since 2000 without being started.
Besides the obvious, gas, gas tank, oil and filter, lube cylinders tires and brakes, what is common problems that need to be address before starting.
Thanks,
Joe

Is this sitting high?

58VetteBoy — Tue, 19 May 2026 22:13:23 GMT

My 1985 coupe is finally back together after the past 1.5 years of my friend putting it back together at his house, and it just needs to be tuned. I went over there today to take a look at it, and to me it seems like the ride height is too high. I also have a 1986 coupe, and I believe it sits lower than this one. I�m wondering if it does look too high and, if so, how much it should be lowered? Sorry for the poor-quality pictures.

Bump stops

MarkGM — Tue, 19 May 2026 19:36:04 GMT

I replaced my FX3 Bilsteins with Ridetech HQ adjustable shocks. This past weekend I tracked the car at Ozarks International Raceway where there is a hard dip in one straight and the car repeatedly bottomed out, with my 275/35 18s rubbing the inside fenderwells badly. See photos. I don't see bumpstops on the suspension anywhere. We're they built into the original shocks?

If so, any advice on adding stops to my new shocks? How big would they need to be? 2" maybe.

Oil cooler

Garrett88 — Tue, 19 May 2026 15:17:34 GMT

How could I go about deleting the oil cooler on my 89 corvette to make room for the oil filter because it is touching the header

1987 corvette sports seat foam

tmracer16 — Tue, 19 May 2026 14:29:26 GMT

Who makes the best seat foam for a 1987 corvette convertible Sports seat?? Thanks Tom