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Bad clutch master cylinder experiences?

H

helldiver14

Passed Driver's Ed
Location
Ohio
So I recently installed a new DKM stage 2 kit and today at 800 miles on the clutch I cannot get the car into any gear after getting off the highway. I could push the pedal to the ground and barely sneak it into gear to get home. Even in first with the clutch fully pressed in, itll creep forward. I got home bled the system and its still just as bad. If I put it in first and start the car with the clutch still fully pressed in, it'll jolt forward and die. Any ideas what the cause could be? Also installed the new slave/throwout included with the kit and did the recommended 500 break in period. Seems like the clutch wont disengage. Also when I pump the clutch, on release it makes an air pumping noise like a bike pump or when you're pumping brakes.
 
vwengineer

vwengineer

Ready to race!
Location
Switzerland
Do you see the clutch MC leaking? It can be the master cylinder but it seems unlikely that it became suddenly that bad without any signs of deterioration, especially 800 miles after you replaced the clutch. Generally with a bad MC the pedal will not come back or it will leak fluid but the clutch works, a bad slave on the other hand might pose clutching problems even though the pedal seem to work properly.

I would first carefully inspect the connections of the clutch line, then get it bleed correctly with a pressure bleeder: on these cars, the slave cylinders are a pain to bleed especially if you didn't prefill it before installing it. If that doesn't work then replace parts but if it's a broken part it's more the slave than the master in my opinion, especially since it's a new part.
 
H

helldiver14

Passed Driver's Ed
Location
Ohio
vwengineer said:
Do you see the clutch MC leaking? It can be the master cylinder but it seems unlikely that it became suddenly that bad without any signs of deterioration, especially 800 miles after you replaced the clutch. Generally with a bad MC the pedal will not come back or it will leak fluid but the clutch works, a bad slave on the other hand might pose clutching problems even though the pedal seem to work properly.

I would first carefully inspect the connections of the clutch line, then get it bleed correctly with a pressure bleeder: on these cars, the slave cylinders are a pain to bleed especially if you didn't prefill it before installing it. If that doesn't work then replace parts but if it's a broken part it's more the slave than the master in my opinion, especially since it's a new part.
Click to expand...

So I found the problem last night. Everytime the clutch was released when bleeding I would hear a air noise almost like a bicycle pump. Upon further inspection, I noticed it was just barely leaking around the base of the bleeder block. By base, I mean the area in which the bleeder screw goes into. I could see tiny bubbles forming around it, which means my bleeder block is screwed. I ordered a new one last night and hopefully thats the problem considering my Slave wasnt getting any fluid.
 
vwengineer

vwengineer

Ready to race!
Location
Switzerland
I don't think the noise you hear when pushing the pedal and bleeding is actually air being sucked in. If I bleed it completely and finish by the pedal method I also hear this noise although there is no air in the lines.

I insist but you should definitely pressure bleed it because on those cars the slave cylinder is lower than the bleed port, it's not possible to gravity bleed it correctly like it is on a car where the bleed port is the lowest part of the system.
 
Das Gespenst

Das Gespenst

Go Kart Champion
Location
Glen Ellyn
So your bleeder block probably caused the issue but I'm pretty sure there is indeed air in the system. You HAVE to keep the master almost overflowing the entire time you bleed the clutch line. It pulls fluid from the top of the rear chamber in the master cylinder reservoir and of the level drops below the pickup tube or will pull air and give you a shot clutch pedal. We never pressure bleed the system when we do clutches at our shop. Just bench bleed the slave and manually bleed as you described. That leaking bleeder block more than likely caused fluid level to drop below the pickup tube in the reservoir and pulled air into the clutch line. Gove it another good bleed and make sure the reservoir is completely topped off every 3 bleeds.
 
H

helldiver14

Passed Driver's Ed
Location
Ohio
I'm gonna try to power bleed the system tonight. I ordered some o rings just in case, because I can hear an air sucking noise where the clutch line meets the bleeder block. If it's none of this, then the only thing left would be the slave...which was just replaced when the clutch was swapped out.
 
H

helldiver14

Passed Driver's Ed
Location
Ohio
So I tried bleeding it tonight and am getting nothing but air. My slave/throwout is squeeking like crazy. So I have no clue what to even do now. I'm beginning to assume that I had a defective slave that went bad. lines are good, and I took off the bleeder block and pressurized both the line to the master and the slave. Both held pressure.
 
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