Clutch pedal travels too low - ZR-1 Net Registry Forums

lfalzarano · 03-02-2022

I had a hydraulic clutch failure. So far the master and slave clutch cylinders have been replaced. The clutch, pressure plate and throw out bearing were also replaced.

A road test revealed depressing the clutch pedal barely allowed me to shift into gear. The clutch pedal started to engage about an inch from the firewall.

What could be the source of the low level pedal engagement with the clutch? The re-bleeding of the clutch hydraulics provided no change in the clutch pedal engagement.

Ideas?

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-=Jeff=- · 03-02-2022

what brand/type Master and Slave? are you sure they are good? (even though they are new)

lfalzarano · 03-02-2022

89-1996 clutch master cylinder from Corvette America. It doesn?t say the maker. They listed as their brand.

On the slave cylinder GM parts bought one that was exactly like the one they removed. No idea of the brand.

I suspect either one is letting air into the system. I can?t be the thickness of the rug hindering engagement. The rugs have been around for many years.

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Shizap · 03-02-2022

What clutch disk did you install? If it's not the hydraulics, it could be a matter of needing to shim the pressure plate if the clutch disk is too thick. Marc Haibeck has an article that talks about Centerforce clutch disks and the recommended amount to shim them.

lfalzarano · 03-02-2022

Quote:

Originally Posted by Shizap

What clutch disk did you install? If it's not the hydraulics, it could be a matter of needing to shim the pressure plate if the clutch disk is too thick. Marc Haibeck has an article that talks about Centerforce clutch disks and the recommended amount to shim them.

Thanks for the tip. I have forwarded the article to the service manager at the Chevy dealership.

The clutch kit and clutch slave cylinder was purchased by the the Chevy parts department. I?ve been feeding your suggestions to the service manager. He is in contact with GM support in trying to solve the pedal travel and hard shifting. I also asked Bill at ZFDoc for his thoughts.

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Young1 · 03-02-2022

I have the best luck to reverse bleed the clutch hydraulics to get all the air out of the slave. Ask them if they did that. Simple things first.

-=Jeff=- · 03-02-2022

If you pump the clutch 50 times does the pedal get better?

WARP TEN · 03-03-2022

Quote:

Originally Posted by -=Jeff=-

If you pump the clutch 50 times does the pedal get better?

No, but his leg gets worse....

--Bob

-=Jeff=- · 03-03-2022

My suggestion was based off of a slave cylinder issue from years ago. Bill B told me to try that. The system is self bleeding

Matt B · 03-03-2022

So maybe BOTH will happen [emoji3]

03-02-2022	#1
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Clutch pedal travels too low I had a hydraulic clutch failure. So far the master and slave clutch cylinders have been replaced. The clutch, pressure plate and throw out bearing were also replaced. A road test revealed depressing the clutch pedal barely allowed me to shift into gear. The clutch pedal started to engage about an inch from the firewall. What could be the source of the low level pedal engagement with the clutch? The re-bleeding of the clutch hydraulics provided no change in the clutch pedal engagement. Ideas? Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR]

03-02-2022	#2
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,136	Re: Clutch pedal travels too low what brand/type Master and Slave? are you sure they are good? (even though they are new) __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - 3" Magnaflow Bullet cats - LT4 Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

03-02-2022	#3
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Re: Clutch pedal travels too low 89-1996 clutch master cylinder from Corvette America. It doesn?t say the maker. They listed as their brand. On the slave cylinder GM parts bought one that was exactly like the one they removed. No idea of the brand. I suspect either one is letting air into the system. I can?t be the thickness of the rug hindering engagement. The rugs have been around for many years. Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR]

03-02-2022	#4
Shizap Join Date: Oct 2020 Location: Coweta, Georgia Posts: 53	Re: Clutch pedal travels too low What clutch disk did you install? If it's not the hydraulics, it could be a matter of needing to shim the pressure plate if the clutch disk is too thick. Marc Haibeck has an article that talks about Centerforce clutch disks and the recommended amount to shim them.

03-02-2022	#6
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 879	Re: Clutch pedal travels too low I have the best luck to reverse bleed the clutch hydraulics to get all the air out of the slave. Ask them if they did that. Simple things first. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

03-02-2022	#7
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,136	Re: Clutch pedal travels too low If you pump the clutch 50 times does the pedal get better? __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - 3" Magnaflow Bullet cats - LT4 Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

03-03-2022	#9
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,136	Re: Clutch pedal travels too low My suggestion was based off of a slave cylinder issue from years ago. Bill B told me to try that. The system is self bleeding __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - 3" Magnaflow Bullet cats - LT4 Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

03-03-2022	#10
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 520	Re: Clutch pedal travels too low So maybe BOTH will happen [emoji3] __________________ ZR-1 #638/1991