At my Solo II event today my clutch pedal decided to stay near the floor. It would come back up but if I kept it engaged it would lose pressure and the clutch would engage. It appears to be the master cylinder or the slave cylinder. How can you tell which one is faulty? The fluid level has not gone down and I cannot see any visual leaks. I don't want to replace the wrong one.

Thanks Steve
84 GSL SE

 

1. Get helper
2. Remove cap from master cyl
3. Have helper press and hold clutch pedal
4. Look to see if the slave cylinder begins to retract on it's own
5. [if yes on 4 have helper re-apply the pedal] Look inside the master cyl reservoir, if you see fluid coming back up while the pedal is held down, the master is bad.
6. look inside the car where the pedals pushrod goes into the back of the master, if it's damp, it's the master.
7. If you have damp fluid around the slave, or if you squeeze the piston boot and fluid comes out, it's the slave.
8. Make sure your soft line doesn't have any cracks or tears.



Word of advice, it's generally a good idea to replace them both at the same time, you can get them for a decent price on rockauto.com as well as a stainless braided line from Mazdatrix and you'll be set.

These are not the cheapest of what they have available on rock auto but I would trust Bendix more than the cheaper alternatives.
Bendix Master Cyl - $32.79 + ship
Bendix Slave Cyl - $16.93 + ship
Mazdatrix Braided Clutch Line - $18 + probably $10 for shipping

 

pull the rubber boot on the slave back. they'll be fluid there if it's leaking. if there's no sign of a leak down the firewall under the master, pull the carpet and padding back in the floor under the pedals. the master could be leaking down the inside of the firewall. the leak down can also be internal. no way of telling which one. but in this situation, normal practice is to replace both, and the flex line going to the slave.

 

Replace both. Cheap insurance.

 

All the advice above is great for diagnosing the problem; however, this advice is the best. Replace it all and get a new line as well. Then you know all the problems are fixed and you won't have to worry about it for another (read your odometer) miles!.

 

If one died, the other isn't far behind.

 

It will be both. They always fail in pairs. It's rare when one fails and you temp fate by not changing the other one.

 

Not rare, but once you replace one with a new part, the other becomes the weakest link, and we all know what happens to weakest links...

Replace both and be done with it.

 

 

Have you seen enough posts to realize you best answer is to replace both?

 

Both have been replaced. Appeared to be the master but the slave was getting sketchy

thanks Steve

 

+1 I eventually had to replace both on my GSL-SE