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STRANGE PROBLEM AGAIN. where to get an uprated clutch master?

3K views 6 replies 5 participants last post by  GR8 WHITE 
#1 ·
Guys,

i have once more experience the very very unusual case of my clutch pedal suddenly being sucked completely to the floor, rendering the car undrivable.

for the avoidance of doubt:

- car is stock apart from headers, intake and corsa
- car has never been drag launched
- car is tracked, but maybe 10%/90% track/street use
- i have checked and replaced the clutch fluid. in every case, it was clean/none of the signs of contamination

to be more precise of the problem:

1) car sitting in traffic, idling normally
2) clutch in to get into first gear
3) clutch pedal suddenly SUCKED straight to the floor seemingly by invisible hand, and it just stays there
4) you can pull the pedal back with your hand or foot, and it springs back into place, but any pressure on the pedal and it is once more sucked strongly back
5) car therefore can't be put into gear

this is NOT a case of the pedal going spongy or soft. it is an on/off situation. once the pedal has been sucked in, that's it. it stays that way. there is also no sign of the problem before it happens; no slowly changing pedal feel. everything is fine, then whoops! it happens.

this has happened to me twice. once at about 6k miles, and again now at about 10k miles. car was one of the first C6 Z06's.

no dealer support in my country, and only two Z06's here, including mine.

it was an easy fix for the shop-- they said something about the rubber boot of the clutch master/actuator "inverting" or going "inside out", resulting in total loss of pressure. so the pedal being sucked in is i think the helper spring of the pedal taking over. the shop just reversed the boot/actuator or whatever it was, and it was ok again.

since that first time it happend over a year ago, i have tracked the car, run it hard to over 160mph and driven it the way it was meant to be driven on many occasions. we (me and my mechanic) thought it was a fluke, but it happened again yesterday.

at the time it happend, i checked the fluid and it was clear/clean. changed it anyway to be sure.

looking back, there were two common conditions at the time of the problem:

1) very very hot summer day-- it is about 97-98 degrees here now;
2) car idling for a very long time at standstill
3) car not driven hard during this period

i'm guessing but maybe its some kind of heat soak or pressure build-up issue? strange that during those times i was tracking the car and driving it hard, it never came up. but on these two instances, with the car sitting in the hot sun idling for a long time, upon slowly finally moving off, the problem showed up.

so is there any kind of uprated clutch master for our cars?

thanks in advance!
 
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#2 ·
Hi,

Don't know of any uprated clutch masters, but yesterday I've got the same news from my mechanic that the clutch master is leaking oil.
Car has 8k miles on it. I've ordered the part from a dealer so that it can be replaced. Fortunately the clutch did continue to work as normal.
But because of the oil leakage, we're replacing the assembly proactively.

Mine is a '07 C6 Z06.

Grtz
Bram
 
#3 · (Edited)
I installed a Tick Performance adjustable master cylinder in my car some time ago. It cured any problems I had with the clutch sticking to the floor and the car refusing to shift at high rpms. IMHO, well worth the cost and time and effort to install it. Just Google "Tick Performance" to get the needed information to order. BTW, what country are you from?

Jimbo
 
#7 ·
Although I never had a sticking, spongey, sinking clutch pedal.....I had high RPM shift issues over 5K on hard acceleration and installing a TICK Adjustable Clutch Master Cylinder cured my issues as well. Not saying this is your definitive answer, but if all else fails, it can't hurt to try. Besides, the TICK allows greater amounts of fluid travel with each press of the clutch.

Keep us informed.
 
#4 ·
Before the "change the fluid" groupies who change their clutch fluid more often then their shorts give the magic bullet solves all ranger/danger story

The master for the C6 is smaller then the one for the C5. Lousy quality design

There is a design flaw where a plastic end cap that holds a rubber pressure seal that is at the end of the shaft that is part of the cylinder and then the other end of the rod is attached to the clutch pedal arm.

The end cap pops off as it just clips on allowing the end seal and a metal end cap to then come off preventing rod and cylinder from functioning as no pressure can force the fluid movement since the compression seal has popped off.

You can take the cylinder apart and use a good glue to prevent that end from popping off and back on.

I have seen this happen to at least a dozen C6s
 
#5 ·
There is a design flaw where a plastic end cap that holds a rubber pressure seal that is at the end of the shaft that is part of the cylinder and then the other end of the rod is attached to the clutch pedal arm.

The end cap pops off as it just clips on allowing the end seal and a metal end cap to then come off preventing rod and cylinder from functioning as no pressure can force the fluid movement since the compression seal has popped off.

You can take the cylinder apart and use a good glue to prevent that end from popping off and back on.
Hmm... is this the part you mean? My mechanic has just confirmed it was this part that "inverted"; the rubber seal part of the "slave".

 
#6 ·
Yes,
the rod end connects to the clutch pedal
at the other end of that rod is a plunger/seal at the end which pops off and is now loose and can turn.
What your tech means is that can be taken apart and that end popped back on the end of rod/piston
It just clips on and can come off at any time and stepping on pedal can force the rod forward enough and that end part snaps on again. If part turns then it cannot mate up with the fitting at end of rod

Best is do what is needed to assure the part cannot pop off again.
Being it is what creates the pressure when rod is in when it comes off then no pressure can happen.
 
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