How do you tell whether its a bad cluch master or slave

[one way]

Hey All

My clutch suddenly barely or doesnt disengage. I imagine it has to be a bad master cylinder or slave cylinder. How do you tell? The slave seems fairly easy to swap out. The master cylinder looks like it can only be changed out by a specially trained octopus.

[Hippie]

It's the one you can't get a wrench on.
Did you try and bleed it? Reservoir full?

[Westy78]

Are we talking Bus or Vanagon? If Bus have you tried adjusting the clutch cable first?

[one way]

Its a vanagon and the resevor is full and I bled it and saw no air in the liquid. The slave still moves.. but it must not move enough. There may also be something internal thats not disengaging the clutch.

Hippie, experience shows that you are going to be right... but I'm hoping this ONE time, it'll be the easy one.

[Hippie]

If you pump the clutch pedal 2 or 3 times clear to the floor and finally get the clutch to operate, it is probably the master cylinder.

I don't know of any way of testing these other than capping or pinching off the slave end of the fluid line to see if you can build and maintain pressure with the master.
One of the lines could be collapsed inside, too, keeping the slave from returning to its rest position, but that should keep the clutch slipping all the time, and when you opened the slave end of the line, the fluid would squirt out of the slave and it would retract fully.

I'd probably just replace the easy one and see what happens.

Anyone got any special tricks? Chime in?

[Amskeptic]

If you pump the clutch pedal 2 or 3 times clear to the floor and finally get the clutch to operate, it is probably the master cylinder.

I don't know of any way of testing these other than capping or pinching off the slave end of the fluid line to see if you can build and maintain pressure with the master.
One of the lines could be collapsed inside, too, keeping the slave from returning to its rest position, but that should keep the clutch slipping all the time, and when you opened the slave end of the line, the fluid would squirt out of the slave and it would retract fully.

I'd probably just replace the easy one and see what happens.

Anyone got any special tricks? Chime in?

Late to the party here, sorry. The cylinder with the wet boot is your culprit.
If they are both wet, replace them both. If they are both dry inside their respective boots, then it is possible that you have internal clutch issues, but an easy test of the hydraulics is to have an assistant pump the pedal up and you look at the range of travel. Keep the pedal on the floor and watch to see if the arm slowly travels back. If it holds for 15-30 seconds, it is still serviceable for a while.
Colin

[Hippie]

The cylinder with the wet boot is your culprit.

(Which, unfortunately, will be the one you can't get a wrench on.)

[one way]

What is the range of travel supposed to be? The Bentley manual doesnt state

[Amskeptic]

What is the range of travel supposed to be? The Bentley manual doesnt state

At the slave it is a "a little"
You can tell by the correspondence between your pedal pusher and the slave cylinder movement. So you say "push" and if the slave moves immediately upon actual pushing and keeps moving until the pedal bottoms on the carpet or mat, that is a full stroke. But really, the important thing to look for is what happens after the pedal has hit and is held to the floor. If the slave starts oozing back and releasing the clutch arm, well . . . . there you go.
Colin