clutch diagnosis: slave vs. master cylinder

[rbogh901]

Has this ever happened to you?

Sitting with the clutch in, car in gear, and engine running the car does not move. Pull it out of gear and the car will start to roll on a minimal grade surface (garage floor). This suggests there is some drag when the clutch is supposedly disengaged. The clutch seems to engage reasonably, not particularly heavy, and no appreciable slippage.

Pedal cluster is rebuilt. Roll pin minimally squished so it was replaced. Plastic bushings replaced. Wasn't real bad but this was definitely helpful and the pedal feel is improved. Glad I did it. Feels so smooth. I thought it was smooth before but it just glides now.

Clutch circuit bled with a Motive. No real improvement. Got the usual manky dark fluid completely flushed so that is nice though.

Is the slave and associated line next or could it be the master cylinder? Seems like somebody said you could tell somehow.

Hoping it's not something more difficult inside the clutch mechanism like the fork or something.

[johnsjmc]

There is a well known issue with corrosion and old grease on the guide tube causing drag. It depends on how long since the clutch was last replaced and if the recommended lubes were used last time. I replaced the slave on my 95 993 and condition improved but remains. i expect to replace the clutch this summer and fix it completely.

[rbogh901]

I replaced the slave on my 95 993 and condition improved but remains. i expect to replace the clutch this summer and fix it completely.


Same symptoms, mildly incomplete disengagement with the clutch pedal all the way in?

Did you replace the rubber line at the same time? I've read that this can be the problem if it's old.

It's a shame to have to do a complete clutch job just because of inadequate lubrication in the guide tube.

On another note, I'd say that flushing the clutch line actually did seem to improve things a bit over the next few drives. Or maybe it's the warmer weather.

[johnsjmc]

I replaced the slave and hose. I had an issue with drag and the pedal not always rising fully.The drag is much much reduced but still there slightly. the pedal rises properly now as well. I have over 110000 mi on the car and may be original if so it is overdue for replacement. I am upgrading to a Lightweight RS flywheel and clutch setup .I am also upgrading the motor mounts to RS at same time I think the engine may be moving around a little under braking with the worn stock mounts. Ocassionally the trans is harder to move out of gear when decelerating i am thinking the drag or bind may be agrevatted by the worn mounts

[rbogh901]

agreed on disengaging gear on deceleration, have to blip the throttle to clear but then I kinda like blipping. lwf will help with that for you. i will probably go that way one day too.



and my mounts are shot so they need to go either way.



what is the feeling regarding slave cylinders, are some better than others?


thx

[rbogh901]

is there anything to know about buying a slave cylinder? OEM manufacturer as good as any?

Porsche 911 Clutch & Flywheel - Page 3