RHDV8

Has anyone ever come across the same problem?
When I start out the clutch engages half way up the pedal travel but each time the clutch pedal is depressed it engages a little higher until it’s at the top of the pedal travel and the clutch starts to slip.
Could it be the slave is sticking out and not returning properly?

When left for a while the engagement is back to halfway.
Any ideas?

Mart00SS

iTrader: (19)

What kind of clutch? Stock? Sounds like air in the hydraulic system to me, the more you pump the clutch, the air is compressed in the system, and the more normal the system works. The only thing that doesnt make sense is that the clutch slips after you pump it several times?? that weird.

RHDV8

Stock clutch on a 2004 GTO but I have made the master cylinder rod adjustable. It's the opposite of what you say though, the more I pump the clutch the worse it gets (all this while I’m driving). I would have thought that if there was air in the system it would be hard to disengage the clutch rather than hard to engage?
Just thinking aloud here but if the fluid was somehow building pressure as I drove/it gets hot, wouldn’t the pressure be released via the reservoir when the pedal is up?
Is it possible that the valves/ports are not opening in the master cylinder to allow the fluid back, i.e. somehow acting only one way, saying that, the fluid level isn’t dropping in the reservoir........ Very confused here

Mart00SS

iTrader: (19)

Did this start happening after you made the mater adjustable? I'd make sure you dont have it adjusted in too far (pedal too high) . I'd also bleed the system.

RHDV8

Thanks for the reply. Yes it did, as when I did this, I swapped master cylinders too. The thing is, the throw on this master cylinder is actually less than on my previous one so it should engage further down. I have adjusted it so that I have limited the throw as much as possible and the system has been well bled and the pedal is always firm.


It seems that for some reason the slave is pushing the throw out bearing and it's not returning and each time the clutch is depressed it gets a little worse.
I know the master is returning ok as it is directly attached to the pedal which comes up ok. What the slave is doing though???????

Mart00SS

iTrader: (19)

So you took a stock master cylinder and made it adjustable? Could be something wrong with the re-assembly not allowing the fluid to fully return to the master cylinder. I've only read the thread on making a stock master adjustable one time, Maybe one of the seals in the master is folded not allowing fluid to return at the proper rate. In turn I would think that the more you pump it, the more pressure would build in the line if the fluid cant return to the master fast enough, but then after allowing time to pass everything turns back to normal as the fluid returns to the master. ??? I'm kinda at a loss and this is just a possible theory

toneloc60

iTrader: (7)

Sounds like air in the system or possibly having the fluid line too close to a heat source. As things heat up, they expand. The more expansion you have in the line the more it pushes on the slave cyl. That would explain the slipping too.

RHDV8

Yep all I did was to put a threaded section between the clutch pedal pivot and the master cylinder piston. Yep I'm at a loss too and very reluctant to drop the box. You would think that if there was a problem with the master cylinder it would be hard to disengage the clutch. The pedal only comes back to halfway after leaving it for quite some time not like 5 mins, it almost seems like it's temperature related.

RHDV8

Thanks for the suggestions but if there was air in the system it would be hard to disengage the clutch not engage it. Also I don’t think that hydraulic fluid expands when hot or else you would have lots of fun with brakes.
But I'm open to all theories

toneloc60

iTrader: (7)

Hydraulic fluid does expand when heated. That is why you are supposted to run steel braided brake line on a race car. Otherwise the added pressure from the heated fluid will expand the rubber line and either rupture it or simply not apply as much pressure to the caliper. Your clutch system, however, is all steel braided.

Just my thoughts. Keep us informed as to what you figure out!

RHDV8

Now I thought that the braided lines were to stop expansion of the line its self when you increase the pressure in the line by applying the brakes rather than just to contain the pressure that occurs because the fluid is getting hot

Keep the ideas coming