1992 Clutch suddenly stopped working - ZR-1 Net Registry Forums

EdCruz320 · 4 Weeks Ago

I was driving around the block showing my brother in law the car (1992 21,000 miles). While slowing to make a right, Ipressed the clutch, and shifted into first (I was going slow). I felt and heard a loud bang and the car started acting as if I sidestepped the clutch. I got to my house and could not disengage the clutch. I was able to get the trans into neutral and pushed it into my driveway.

Thinking it might be hydraulic, I replaced the clutch master and slave cylinders. I looked at the clutch fork (couldn't see much) and it looked and felt ok. At this point I think it's a bad pressure plate but am wondering if it can be anything else.

The car is completely stock. I'd like a stock clutch. Thoughts on what I should order? Any help would be appreciated.

Thanks

AlbanyBrian · 4 Weeks Ago

It seems to me that you should go through a diagnosis process that starts with looking at the clutch pedal to make sure nothing broke there, then the clutch master cylinder, the slave cylinder, the hydraulic line between these two. If they look ok visually then take the slave off the bellhousing and see what it looks like. Is the push rod look correct; can you push it back into the slave and will it extend when the clutch pedal is pushed in (very slowly). If this system seems to be working correctly then you'll need to look into the clutch which maybe you can due to some extent with an endoscope camera, otherwise it is a transmission out so you can remove the bellhousing and see the clutch. I have not experienced the issue you describe, but based on what you describe this is how I would try to diagnose the problem. Maybe others who have had a similar experience as you will offer their insights. Good luck, Brian

HAWAIIZR-1 · 4 Weeks Ago

I agree with Brian more detailed checks needed. With only 21,000miles it is hard to imagine clutch fork or pressure plate broken. But were you able to tell if the clip to hold to pivot ball was still good and the fork connected? Depending the environment I?m not sure if the clip assembly couldn?t rust out and break, the bang you hear? Pressure plate also seems so unlikely on a low miles car. Did you do the work yourself to replace the master and slave and how did it bleed?

EdCruz320 · 4 Weeks Ago

Given the suddenness of the bang, it would make sense that the clip broke (or something happened to the pivot ball). I couldn't see into the bell housing (even with a bore scope) to verify. But if I pull the trans to check, I think it would make sense to install a new fork (unless the clip is separate) and new clutch kit though I'm not convinced the pressure plate failed. The car is pretty spotless and was stored indoors so I don't think it will be catastrophic in there. I'm just trying to gauge the likelihood of failure of this various components under the circumstances.

Oh and the clutch pedal, and new hydraulics all appear to be working properly

WARP TEN · 4 Weeks Ago

I have had two instances of a failed clutch, and as a result I am now an expert at driving a car in traffic without a clutch. The first was a long time ago on a Saab 99 when I did indeed break a clutch fork in Denver on my way home in rush hour traffic. Just snapped in half; the Saab expert said he had never seen it before. So I definitely would look for something like that. The other time was with my '93 ZR-1 on a Friday afternoon in Indiana returning from a business appointment. Turned out to be a slow leak in the hydraulic system; I just ran out of clutch fluid. Since you have addressed that, probably not an issue. At the time I was lucky enough to find a small local Chevy dealer in rural Indiana just before closing. This was in about 1996 and the mechanics had never seen a ZR-1. They were so excited that they added fluid to temporarily solve the problem so I could get home north of Chicago. And they didn't even charge me for it, but it seemed to make their day. So yeah, as suggested by others, take a look at the clutch fork. They do sometimes break. --Bob

A26B · 4 Weeks Ago

Check out this thread for ZR-1 broken clutch fork. This has been known to occur infrequently but no unheard of.

https://www.zr1.net/forum/showthread...nt+clutch+fork

Likewise the release/throwout bearing has also failed in a similar manner.

HAWAIIZR-1 · 4 Weeks Ago

Quote:

Originally Posted by EdCruz320

Given the suddenness of the bang, it would make sense that the clip broke (or something happened to the pivot ball). I couldn't see into the bell housing (even with a bore scope) to verify. But if I pull the trans to check, I think it would make sense to install a new fork (unless the clip is separate) and new clutch kit though I'm not convinced the pressure plate failed. The car is pretty spotless and was stored indoors so I don't think it will be catastrophic in there. I'm just trying to gauge the likelihood of failure of this various components under the circumstances.

Oh and the clutch pedal, and new hydraulics all appear to be working properly

Okay, got it. Not many components left to check, but more importantly the cause. I guess even a low miles clutch fork could snap suddenly. If you find you need a fork I have an extra NOS one. Best wishes.

A26B · 4 Weeks Ago

Quote:

Originally Posted by HAWAIIZR-1

Okay, got it. Not many components left to check, but more importantly the cause. I guess even a low miles clutch fork could snap suddenly. If you find you need a fork I have an extra NOS one. Best wishes.

I think so. They are stamped steel and there are stress points visible, even in a new one. I have thought that with a small oxy/acetylene welding tip, the stress points could be fused and eliminated, before installation.

HAWAIIZR-1 · 4 Weeks Ago

Quote:

Originally Posted by A26B

I think so. They are stamped steel and there are stress points visible, even in a new one. I have thought that with a small oxy/acetylene welding tip, the stress points could be fused and eliminated, before installation.

I see what you mean Jerry. Those bends look stressed for sure. I will definitely consider reinforcement at clutch time on my new or used fork before install. Thanks.

kieranod1 · 3 Weeks Ago

Not for nothing guys, but I had a clutch failure a few years back. while down shifting I heard a pop and then the clutch pedal went right to the floor. I was able to nurse her home by timing stop lights ahead and feeling for the next gear and slipping it in. We dropped the tranny and found the shoulders of the throwout bearing had sheared off.

4 Weeks Ago	#1
EdCruz320 Join Date: Dec 2023 Location: Miami, Florida Posts: 4	1992 Clutch suddenly stopped working I was driving around the block showing my brother in law the car (1992 21,000 miles). While slowing to make a right, Ipressed the clutch, and shifted into first (I was going slow). I felt and heard a loud bang and the car started acting as if I sidestepped the clutch. I got to my house and could not disengage the clutch. I was able to get the trans into neutral and pushed it into my driveway. Thinking it might be hydraulic, I replaced the clutch master and slave cylinders. I looked at the clutch fork (couldn't see much) and it looked and felt ok. At this point I think it's a bad pressure plate but am wondering if it can be anything else. The car is completely stock. I'd like a stock clutch. Thoughts on what I should order? Any help would be appreciated. Thanks

4 Weeks Ago	#2
AlbanyBrian Join Date: Feb 2023 Location: Albany, OR Posts: 44	Re: 1992 Clutch suddenly stopped working It seems to me that you should go through a diagnosis process that starts with looking at the clutch pedal to make sure nothing broke there, then the clutch master cylinder, the slave cylinder, the hydraulic line between these two. If they look ok visually then take the slave off the bellhousing and see what it looks like. Is the push rod look correct; can you push it back into the slave and will it extend when the clutch pedal is pushed in (very slowly). If this system seems to be working correctly then you'll need to look into the clutch which maybe you can due to some extent with an endoscope camera, otherwise it is a transmission out so you can remove the bellhousing and see the clutch. I have not experienced the issue you describe, but based on what you describe this is how I would try to diagnose the problem. Maybe others who have had a similar experience as you will offer their insights. Good luck, Brian __________________ 1993 ZR-1, #135, cool car 2008 Z06, fun car 1985 RIP, was a fun project/track car

4 Weeks Ago	#4
EdCruz320 Join Date: Dec 2023 Location: Miami, Florida Posts: 4	Re: 1992 Clutch suddenly stopped working Given the suddenness of the bang, it would make sense that the clip broke (or something happened to the pivot ball). I couldn't see into the bell housing (even with a bore scope) to verify. But if I pull the trans to check, I think it would make sense to install a new fork (unless the clip is separate) and new clutch kit though I'm not convinced the pressure plate failed. The car is pretty spotless and was stored indoors so I don't think it will be catastrophic in there. I'm just trying to gauge the likelihood of failure of this various components under the circumstances. Oh and the clutch pedal, and new hydraulics all appear to be working properly

4 Weeks Ago	#5
WARP TEN Join Date: Apr 2007 Location: Lake Bluff, IL Posts: 2,153	Re: 1992 Clutch suddenly stopped working I have had two instances of a failed clutch, and as a result I am now an expert at driving a car in traffic without a clutch. The first was a long time ago on a Saab 99 when I did indeed break a clutch fork in Denver on my way home in rush hour traffic. Just snapped in half; the Saab expert said he had never seen it before. So I definitely would look for something like that. The other time was with my '93 ZR-1 on a Friday afternoon in Indiana returning from a business appointment. Turned out to be a slow leak in the hydraulic system; I just ran out of clutch fluid. Since you have addressed that, probably not an issue. At the time I was lucky enough to find a small local Chevy dealer in rural Indiana just before closing. This was in about 1996 and the mechanics had never seen a ZR-1. They were so excited that they added fluid to temporarily solve the problem so I could get home north of Chicago. And they didn't even charge me for it, but it seemed to make their day. So yeah, as suggested by others, take a look at the clutch fork. They do sometimes break. --Bob __________________ 2016 Long Beach Red Z06 #10281 "POPS Z" 1995 Polo Green #409 "WARP TEN"--Haibeck 350/510 package, 4.10s, Hurst, Stock Exhaust with QTP Cutouts --Sold but still running strong 1993 Quasar Blue #161 "HIL KING" --Sold but still running strong, now with more than 120,000 miles 1967 Marlboro Maroon/Saddle Corvette Coupe 300 hp/4-spd --Sold a long time ago ZR-1 Net Registry Founding Member #95 NCM Lifetime Member Favorite Quote--Attributed to Mickey Thompson: "Too Much Horsepower is Almost Enough"

4 Weeks Ago	#6
A26B Join Date: Dec 2003 Location: Arcadia, OK Posts: 3,404	Re: 1992 Clutch suddenly stopped working Check out this thread for ZR-1 broken clutch fork. This has been known to occur infrequently but no unheard of. https://www.zr1.net/forum/showthread...nt+clutch+fork Likewise the release/throwout bearing has also failed in a similar manner. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. Last edited by A26B; 4 Weeks Ago at 11:28 AM.*

3 Weeks Ago	#10
kieranod1 Join Date: Mar 2016 Location: Pittsboro,NC Posts: 23	Re: 1992 Clutch suddenly stopped working Not for nothing guys, but I had a clutch failure a few years back. while down shifting I heard a pop and then the clutch pedal went right to the floor. I was able to nurse her home by timing stop lights ahead and feeling for the next gear and slipping it in. We dropped the tranny and found the shoulders of the throwout bearing had sheared off.