Clutch slipping some; master cylinder / relief valve?

[LugNut]

The 2001 SE Sedan, with the SPI that I rebuilt and put in a new clutch about a year ago, now has a slipping clutch. The driver (not me) is very experienced with manual transmissions, so I thinking it's not from driver error.

I just had the car for a bit this morning. There's no leakage of oil from the vent at the bottom of the bellhousing, so a bad engine rear seal is not likely.

From the FSM, the hydraulic clutch is not adjustable. Clutch pedal operates correctly. Hydraulic fluid in the shared reservoir (brakes and clutch; not a better idea!) is clean and full.

From a test drive, it is slipping some in all gears, but does slowly engage. If not a bad clutch set ($700+ by a shop), my other guess is a bad/clogged hydraulic pressure relief that is slowing the release of the throw-out bearing. I'm also assuming the relief valve is part of the master cylinder.

Sound possible? Or better yet, solved the same yourself?

A new master cylinder is only $35, but a pain to install. I see this good thread on how to do it:

http://www.focusfanatics.com/forum/showthread.php?t=243148

Thanks!

[Sponsor]

[sailor]

From VERY recent experience (grin), I learned that the clutch return spring can be missing for a LONG time (broken off & disappeared) WITHOUT much in the way of symptoms.

Occasional slow engagement (slipping) and occasional need to lift the clutch pedal to engage the cruise control.

Installing a spring when the leaking master was replaced solved the issues....

Worth a check B4 diving deeper...

[LugNut]

Hmmmm ... I did look up under the dash to look for sloppiness in the pedal, etc., but don't remember looking at/for the spring. Will definitely notice the next time, but that will likely be next weekend or so if I replace the master cylinder.

Thanks.

Any others' experiences/"external" repairs for this problem?

[jetrinka]

Worn clutch. The pressure plate fingers provide more than enough "push" to return the pedal effectively. There isn't any relief valve either. Its just a straight shot out of the master to the slave and back again.

[sailor]

Agreed, worn matches the symptoms. We don't know mileage or condition/replacement of flywheel yet when the clutch was "replaced".

New Clutch on an old, worn flywheel seldom lasts long....

[amc49]

Uh, technically there IS a relief valve, the compensation port at master, if clogged or corroded it could easily hold the clutch fingers down. I don't screw with hydraulic clutches much but the cylinders are same basic design as brake and I've seen plenty of brake cylinders with that port clogged pretty solid to lock brakes up and car won't budge.

Worn disc most likely.

[LugNut]

Thanks -- I will likely try replacing the master cylinder first ($35 locally).

I found my old pics of the flywheel. It looked quite good after a light refinishing, and from experience my clutches have done well with such. So if not the master cylinder or defective materials, it's looking like driver error. That's bad news because they are needy, and are to keep this gift car longterm.

The clutch set was a LuK. Anyone had bad luck with Luk?

[sailor]

The identical to stock master cyl. I just installed was an LuK (German), so that could match stock. Good Rep. AFAIK

Hope you get Lucky, and can keep it going for them cheaply.

[LugNut]

Luck not on my side -- for this, nor the $250MM Powerball drawing.

Did the work yesterday morning. 11 month-old fluid came out rusty color, but not lumpy. New clutch master cylinder was identical to the original (LuK brand). No difference in the clutch operation, darn it.