Weird clutch issue on 1998 Boxster
 

Hey guys, new here and trying to help my father-in-law with an issue on his 1998 Porsche Boxster (Not S). After going a long while being neglected for maintenance, he replaced at 120k miles the IMS bearing and while he was at it replaced the clutch plate, flywheel, pressure plate, throw-out bearing, clutch slave cylinder, and clutch master cylinder. Everything fires back up fine and the car is drive-able, however the clutch pedal seems EXTREMELY light and soft and even with the clutch fully disengaged you can smell clutch burning and can feel "chattering".

At first glance to me it sounded like an improperly bled clutch system, but would this cause the clutch to barely make contact even without touching the clutch pedal, leading to the burning smell and odd drive feeling? He's pretty confident that the system is bled, but I'm not as sure.

Sorry ahead of time if this is something very obvious.

Thanks,
Kenny

This definitely sounds like a hydraulic issue.

The clutch/brakes system should be flushed if maintenance has been neglected (it’s super easy, just did mine last night in under an hour). A power bleeder makes all the difference. Motive is the popular brand and they run between $50-$70. I built my own for ~$20 with a $5 hand sprayer from Harbor Freight.

Be sure to follow the correct procedure for both the clutch and brakes (clutch pedal needs to be fully depressed when bleeding).

+1 for the power bleeder. I have a Motive. I can't ever imagine doing a brake job again without one.

+2 . . . . power bleeder is simple, clean and can be done alone.

Thanks all. I'll order a power bleeder this evening and will give it a shot!

- Kenny

So we ran through the shop procedure to properly bleed the clutch hydraulic system (fill power bleeder, attach to reservoir, pump to ~20 psi, hold clutch pedal to the floor, and bleed for 20 seconds) and didn't see any difference. We repeated the procedure another three times and we did get a SMALL amount of air out, but the symptoms are overall unchanged, to include:
- Clutch feels very, very soft but DOES return by itself to its natural position
- When you press the pedal, it's very squeaky, similar to this video I found: https://www.dropbox.com/s/f4sd1ger3jo0j1k/20170419_195542.mp4?dl=0
- At idle, everything appears to be fine, but when in gear and the clutch is completely released it still slips and chatters. After a few moments in gear, you can smell burning clutch. No bueno.

Any ideas? I'm thinking it's possible one of the parts replaced may be bad, but I'm not even sure where to begin as I'm certainly not an expert by any means.

Thanks,
Kenny

So what you're saying is that the clutch is not fully engaging and slips? If that's the case, I think you've been concentrating your efforts in the wrong direction. I don't think it has anything to do with the pedal, fluid or slave cylinder. To be sure, you can try removing the slave cylinder altogether and I'll bet you'll have the exact same symptoms. The fact that the pedal returns could simply be because the pedal itself has a return spring.

Seems to me like something went wrong with the clutch/pressure plate installation. Sadly, you'll have to remove the tranny and inspect everything. It could be a faulty pressure plate. It could be the throwout bearing somehow jammed and not releasing completely, although I don't know what would cause that. Whatever it is, something is amiss inside there and they only way to figure out what's going on is to pull the tranny. Sorry.

P.S. Did you pay attention to the orientation of the clutch plate itself when you installed it? It has a flywheel side and a tranny side. Installing it backwards could cause the issues you're having.

HOW MANY MILES SINCE THE 120K-MILE REPLACEMENT OF THE CLUTCH?
whoops.... sorry... caps lock was on....
but really:
How many miles have been driven since that clutch was replaced?

Good question, Maytag. I was under the impression they just changed it, but now that I re-read the OP, it's not exactly clear.

Ummm...your original post said that your clutch was slipping with the clutch fully disengaged.

Now you’re saying that it slips with the clutch pedal fully disengaged. Those are two polar opposite things and your current issue would not be caused by hydraulics.

Take it back apart...