Well my clutch pedal never returned...
08-31-2014, 01:12 AM
#1
Drifting
Thread Starter
Well my clutch pedal never returned...
I was autocrossing my 2009 Z06 today and on the last run of the day, I was going for a downshift. I touched the clutch and just felt it suck to the floor and that was it. It was towards the end of the course so I just finished out in 2nd gear. I tried pumping the pedal by hand probably 100 times and had no pressure at all, and yes there was fluid in the reservoir. I could not detect any leak either.
I had looked at getting a Tick Performance master cylinder a few weeks ago, but I decided I would hold off on it and do it as a winter project. Well that plan went out the window as I just placed my order for the Tick. I already have the old master cylinder out so hopefully the install will go relatively quick and hopefully it will make my clutch function again!
All in all, it was still a fun day!
I had looked at getting a Tick Performance master cylinder a few weeks ago, but I decided I would hold off on it and do it as a winter project. Well that plan went out the window as I just placed my order for the Tick. I already have the old master cylinder out so hopefully the install will go relatively quick and hopefully it will make my clutch function again!
All in all, it was still a fun day!
08-31-2014, 01:43 AM
#3
Safety Car
Slave or jacked up synchros. Been here many times, and it's never been cheap to repair. You can yank the pedal up and it will operate but I'd have it looked at soon.
08-31-2014, 09:35 AM
#6
Melting Slicks
08-31-2014, 10:22 AM
#7
geez!!! that looks pretty bad bro....may wanna try replacing the fluid before each race...thats what i do...for serious racers use castrol srf racing fluid...$70 a bottle though...
08-31-2014, 10:58 AM
#8
Drifting
Thread Starter
That wasn't gunk.
Its a plastic and rubber piece that's part of the cup seal that was supposed to be on the end of the piston that came off and they both wedge each other.
Well, hopefully the seals in the right place
Its a plastic and rubber piece that's part of the cup seal that was supposed to be on the end of the piston that came off and they both wedge each other.
Well, hopefully the seals in the right place
Last edited by ttx350z; 08-31-2014 at 11:19 AM. Reason: added pictures
08-31-2014, 03:13 PM
#9
Safety Car
interesting thread, I'm looking at a 2010 M6 GS, when you get it back together please let us know how it works ..... 
Last edited by vt65; 08-31-2014 at 03:17 PM.
08-31-2014, 04:11 PM
#10
Drifting
Thread Starter
Well I got it put back together and reinstalled and bled in about 40 minutes.
I test drove it down the street and everything felt fine.
Autocross time!! It worked with no issues! I'm still gonna be replacing it with the Tick once it arrives. I'm just happy that it worked and it wasn't a bad slave!
I test drove it down the street and everything felt fine.
Autocross time!! It worked with no issues! I'm still gonna be replacing it with the Tick once it arrives. I'm just happy that it worked and it wasn't a bad slave!
08-31-2014, 04:20 PM
#12
Safety Car
08-31-2014, 07:58 PM
#13
The black in contaminated clutch fluid/on the bottom of the reserve tank is clutch dust and very abrasive.
Note, the black floating at the top of the tank is parts of the rubber seals and plungers.
So the abrasive clutch dust in the fluid, cause the seal to wear faster.
Hence, start using the ranger method to keep the fluid clean.
Note, the black floating at the top of the tank is parts of the rubber seals and plungers.
So the abrasive clutch dust in the fluid, cause the seal to wear faster.
Hence, start using the ranger method to keep the fluid clean.
09-01-2014, 06:32 PM
#16
Drifting
Thread Starter
That's interesting. I wonder how many of the clutch pedal failures are actually caused by this and not just dirty fluids. Dirty fluids cutting up seals is one thing, but to have the cup seal completely fall off is another.
Last edited by ttx350z; 09-01-2014 at 06:37 PM.
09-01-2014, 11:58 PM
#17
It is not actually the cup plug. It is a small plunger in the center of the piston that blocks fluid flow back to the reservoir when applying pressure to the cylinder. The cup plug is on the outer edge of the piston. By the looks of it, makes perfect sense that dirty clutch fluid would cause it to hang up and cause a pedal that does not return. And a fluid service may correct it. In my case, having very clean fluid, I think on occasion the restrictor in the line with the presence of the pedal return spring, causes too much vacuum on the port and causes the whole plunger to dislodge during very fast shifting maneuvers.
I'm no engineer and I'm sure there are several weak points to this hydraulic system. However I own a repair shop and have never seen hydraulic issues in clutch systems like I do on these cars being corrected so many times by just doing fluid services. Has to be a reason behind it. This seems suspect to me.
I'm no engineer and I'm sure there are several weak points to this hydraulic system. However I own a repair shop and have never seen hydraulic issues in clutch systems like I do on these cars being corrected so many times by just doing fluid services. Has to be a reason behind it. This seems suspect to me.
09-02-2014, 12:38 AM
#18
live4toys,
If you want to short bus it, its the three orifice restrictors that GM installed in the fluid line. One is at the line to master cylinder, the next at the quick disconnect coupling, and the third at the slave to line.
Granted that they state they were installed such to allow the drive line to last clutch dumps, but even when the fluid is clean, its at the cost to the clutch itself (just ends up spinning/burning up, instead of a rock solid lock up when you let the clutch out fast).
Now throw in contaminated clutch fluid that slows down the return of the fluid back to the master cylinder through the restrictions, and it start to bring up a whole set of problems instead (maybe this one of them).
Worst yet, GM did not use a slave cylinder that is sealed off/ will push the clutch dust back forward of the plunger as it stocks forward to keep the clutch dust out of the fluid, and to really chuck salt into the wound, put the slave cylinder bleeder in such a location, that you have to pull the torque tube cover to get to it if you are planning on power bleeding the system to get all the clutch dust out of the lines.
As for a solution to the problem in regards to fast fluid return, it's to remove the in line restictors (drill them out), but you just cut your safety net, and if you get stupid clutch dumping, kiss the drive line goodby.
As for the power bleeding problem (access to the bleeder valve), a remote bleeder will take car of that.
As for a better slave cylinder that is less prone to packing the fluid with clutch dust, there out there, but at $1k a pop.
To be blunt, GM dropped a 400/430/505/620HP motor in the vets, but did not spend the time to bullet proof the drive lines for that amount of HP. Instead, they hobble the motors with TM, and use the clutch (that they don't warranty if it burns out) as the sacrificial lamb to protect the parts that they do warranty instead.
If you want to short bus it, its the three orifice restrictors that GM installed in the fluid line. One is at the line to master cylinder, the next at the quick disconnect coupling, and the third at the slave to line.
Granted that they state they were installed such to allow the drive line to last clutch dumps, but even when the fluid is clean, its at the cost to the clutch itself (just ends up spinning/burning up, instead of a rock solid lock up when you let the clutch out fast).
Now throw in contaminated clutch fluid that slows down the return of the fluid back to the master cylinder through the restrictions, and it start to bring up a whole set of problems instead (maybe this one of them).
Worst yet, GM did not use a slave cylinder that is sealed off/ will push the clutch dust back forward of the plunger as it stocks forward to keep the clutch dust out of the fluid, and to really chuck salt into the wound, put the slave cylinder bleeder in such a location, that you have to pull the torque tube cover to get to it if you are planning on power bleeding the system to get all the clutch dust out of the lines.
As for a solution to the problem in regards to fast fluid return, it's to remove the in line restictors (drill them out), but you just cut your safety net, and if you get stupid clutch dumping, kiss the drive line goodby.
As for the power bleeding problem (access to the bleeder valve), a remote bleeder will take car of that.
As for a better slave cylinder that is less prone to packing the fluid with clutch dust, there out there, but at $1k a pop.
To be blunt, GM dropped a 400/430/505/620HP motor in the vets, but did not spend the time to bullet proof the drive lines for that amount of HP. Instead, they hobble the motors with TM, and use the clutch (that they don't warranty if it burns out) as the sacrificial lamb to protect the parts that they do warranty instead.
09-02-2014, 01:23 AM
#19
live4toys,
If you want to short bus it, its the three orifice restrictors that GM installed in the fluid line. One is at the line to master cylinder, the next at the quick disconnect coupling, and the third at the slave to line.
Granted that they state they were installed such to allow the drive line to last clutch dumps, but even when the fluid is clean, its at the cost to the clutch itself (just ends up spinning/burning up, instead of a rock solid lock up when you let the clutch out fast).
Now throw in contaminated clutch fluid that slows down the return of the fluid back to the master cylinder through the restrictions, and it start to bring up a whole set of problems instead (maybe this one of them).
Worst yet, GM did not use a slave cylinder that is sealed off/ will push the clutch dust back forward of the plunger as it stocks forward to keep the clutch dust out of the fluid, and to really chuck salt into the wound, put the slave cylinder bleeder in such a location, that you have to pull the torque tube cover to get to it if you are planning on power bleeding the system to get all the clutch dust out of the lines.
As for a solution to the problem in regards to fast fluid return, it's to remove the in line restictors (drill them out), but you just cut your safety net, and if you get stupid clutch dumping, kiss the drive line goodby.
As for the power bleeding problem (access to the bleeder valve), a remote bleeder will take car of that.
As for a better slave cylinder that is less prone to packing the fluid with clutch dust, there out there, but at $1k a pop.
To be blunt, GM dropped a 400/430/505/620HP motor in the vets, but did not spend the time to bullet proof the drive lines for that amount of HP. Instead, they hobble the motors with TM, and use the clutch (that they don't warranty if it burns out) as the sacrificial lamb to protect the parts that they do warranty instead.
If you want to short bus it, its the three orifice restrictors that GM installed in the fluid line. One is at the line to master cylinder, the next at the quick disconnect coupling, and the third at the slave to line.
Granted that they state they were installed such to allow the drive line to last clutch dumps, but even when the fluid is clean, its at the cost to the clutch itself (just ends up spinning/burning up, instead of a rock solid lock up when you let the clutch out fast).
Now throw in contaminated clutch fluid that slows down the return of the fluid back to the master cylinder through the restrictions, and it start to bring up a whole set of problems instead (maybe this one of them).
Worst yet, GM did not use a slave cylinder that is sealed off/ will push the clutch dust back forward of the plunger as it stocks forward to keep the clutch dust out of the fluid, and to really chuck salt into the wound, put the slave cylinder bleeder in such a location, that you have to pull the torque tube cover to get to it if you are planning on power bleeding the system to get all the clutch dust out of the lines.
As for a solution to the problem in regards to fast fluid return, it's to remove the in line restictors (drill them out), but you just cut your safety net, and if you get stupid clutch dumping, kiss the drive line goodby.
As for the power bleeding problem (access to the bleeder valve), a remote bleeder will take car of that.
As for a better slave cylinder that is less prone to packing the fluid with clutch dust, there out there, but at $1k a pop.
To be blunt, GM dropped a 400/430/505/620HP motor in the vets, but did not spend the time to bullet proof the drive lines for that amount of HP. Instead, they hobble the motors with TM, and use the clutch (that they don't warranty if it burns out) as the sacrificial lamb to protect the parts that they do warranty instead.
I did look for restictors in system upon disassemble and found one in the line at master cylinder. I researched and didn't find much info on the c6 system. I found a lot on the c5 and f- body but the restrictors did not appear to be in Those locations. Would love more info on that though.
09-02-2014, 02:26 AM
#20
That seems to be the general idea. I did replace clutch on my car as well and after seeing what happened in the master removed return spring from pedal to allow the slave to return pedal manually, idea was to remove negative pressure from port with clutch return spring pulling up on the pedal as it returns.
I did look for restictors in system upon disassemble and found one in the line at master cylinder. I researched and didn't find much info on the c6 system. I found a lot on the c5 and f- body but the restrictors did not appear to be in Those locations. Would love more info on that though.
I did look for restictors in system upon disassemble and found one in the line at master cylinder. I researched and didn't find much info on the c6 system. I found a lot on the c5 and f- body but the restrictors did not appear to be in Those locations. Would love more info on that though.
To remove them, just drill them out with the drill bit you are already using to check for them, and make sure to get all the drill swaft out of the lines afterwards.
http://www.superchevy.com/how-to/39021/
Also, when you have the slave cylinder in hand and the hose removed, double check the passage alignment between the end of the hose fitting opening, and the slave passage channel below it. they are often not passage aligned, and slave passage may need to be cleaned up (over sized to align) as well.
