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Old 03-02-2022   #1
lfalzarano
 
Join Date: Feb 2011
Location: Clayton, North Carolina
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Default 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?


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Old 03-02-2022   #2
-=Jeff=-
 
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Default Re: Clutch pedal travels too low

what brand/type Master and Slave? are you sure they are good? (even though they are new)
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Old 03-02-2022   #3
lfalzarano
 
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Default 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.


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Old 03-02-2022   #4
Shizap
 
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Default 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.
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Old 03-02-2022   #5
lfalzarano
 
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Default Re: Clutch pedal travels too low

Quote:
Originally Posted by Shizap View Post
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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Old 03-02-2022   #6
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Default 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.
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Old 03-03-2022   #7
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Default Re: Clutch pedal travels too low

Quote:
Originally Posted by Young1 View Post
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.
I'm not familair with the term "reverse bleed". What is that, zackly?
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Old 03-03-2022   #8
Paul Workman
 
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Default Re: Clutch pedal travels too low

I have bled the clutches on both the Zs by drawing fluid into the system via the slave cylinder -exercising and coordinating the bleeder valve and slave's pushrod to pull in fresh fluid and purge air out of the system. (It's VERY quick and IMO much more efficient than pumping the clutch pedal dozens of times (and I've done it both ways & would never return to the pedal pumping routine...unless I'm on my bicycle!))
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90 #1202
"FBI" top end ported & relieved
Cam timing by "Pete the Greek"
Sans secondaries
Chip & dyno tuning by Haibeck Automotive
SW headers, X-pipe, MF muffs

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Old 03-03-2022   #9
-=Jeff=-
 
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Default Re: Clutch pedal travels too low

Quote:
Originally Posted by Paul Workman View Post
I'm not familair with the term "reverse bleed". What is that, zackly?
Pushing fluid up through the slave.. i have a Phoenix Injector for that task
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Old 03-04-2022   #10
Paul Workman
 
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Default Re: Clutch pedal travels too low

Quote:
Originally Posted by -=Jeff=- View Post
Pushing fluid up through the slave.. i have a Phoenix Injector for that task
Yeah, thanx! And, in conjunction w/ the '91-95 slave (bleeder on the bottom) I see how that tool would really be nice to purge the system.

Got pix?
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90 #1202
"FBI" top end ported & relieved
Cam timing by "Pete the Greek"
Sans secondaries
Chip & dyno tuning by Haibeck Automotive
SW headers, X-pipe, MF muffs

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