Lost the clutch, but it came back?

Zeke · 01:32 PM

I got stuck in massive 45 minute traffic jam on a 6% grade going up hill with no off ramps and no emergency lane. (Yep, that's SoCal for you.) Top speed was below idle in 1st for 5 miles. When I got into open space, the clutch just spun on me. I coasted off the freeway and nursed the car to a rest at a Denny's to consider my options. When I got back in the car after a half hour, the clutch held enough to nurse the car home on the flatter freeways adding a bout 20 extra miles to the trip home. It seems fine now, how does that play out?

I mean I romped on it in the last mile and it held all the way. I know slippage when it starts and it seems OK. Can the Boxster clutch become too hot and then save itself if you catch the problem right away as I did?

BTW, I was about 3 clutch operations from being left dead in lane no. one. It would have taken over a hour for a truck to reach me and I would have blocked a whole lane for that hour. That's my last SoCal trip for fun.

Zeke · 08-31-2008, 06:23 PM

Well. I can see this BBS is useless. i posted on PPBB. We'll see.

lilredpo · 09-02-2008, 02:15 PM

Quote:

Originally Posted by milt

Well. I can see this BBS is useless.

And 16 thousand posts in 6 years.....priceless!

Zeke · 09-02-2008, 05:06 PM

Quote:

Originally Posted by lilredpo

And 16 thousand posts in 6 years.....priceless!

Well, the Boxster part is useless.

However, the PPBB BBS has not given me any insight to what happened. I'm starting to conclude that Boxster owners know little about working on cars. And, they are different cars than what I've had before (which is more than 50 classics and 7 Porsches).

deanp · 09-02-2008, 06:19 PM

I've been waiting to see if anyone was going to answer you. We haven't had the clutch in ours act like that, but it has slipped a little after repeated usage on on hill backed up to a traffic light. Could smell it a little, but that has only happened once that I know of. Any odd smells or did the pedal just go away?

I've seen 'some' decent answers over at renntech, but not many. Agree the DIY aspect on these cars hasn't started picking up yet, even though they seem to be easy to work on. I am glad they put the MAF sensor where you can get to it easily as I pulled it three times in three weeks, once to clean, once to confirm the part number and once to replace....

lilredpo · 09-03-2008, 05:07 AM

I have to agree the Boxster board is not as robust as others and probably due to the relative newness of the species. As Boxsters age, the DIY will pickup. I am often lurking on many other boards as well, it gives you a broader perspective.

Good luck!

Zeke · 09-03-2008, 11:17 AM

Quote:

Originally Posted by deanp

I've been waiting to see if anyone was going to answer you. We haven't had the clutch in ours act like that, but it has slipped a little after repeated usage on on hill backed up to a traffic light. Could smell it a little, but that has only happened once that I know of. Any odd smells or did the pedal just go away?

No problem with the pedal, it acted normally. To tell the absolute truth, after sitting in traffic going uphill for 45 minutes at less than idle speed, I had to use the clutch a lot. I tried to sit in place for a moment and let a gap appear to the car ahead. Of course the a$$ bite behind me couldn't grasp the concept (so many of these dumb shhits on the road these days that it's not even fun to drive anymore).

When I passed the incident (which was a motorhome that literally burned to the ground), I nailed it. I was ready to hit triple digits just air my mind out. I hit 3rd, didn't really wind it out, maybe 5K, then 4th. As I put the foot down I heard the motor start to rev. I lifted and hit the gas again with the same results. I probably let it slip less than a half second each time. At that point I said, "We've lost the clutch."

So, I moved to get off the freeway and let the car rest as I mentioned. It went to work with the wife 2 days now and she reports that everything is normal to her feel. And, she is the daily driver of the thing. I may have dodged a bullet.

Wayne 962 · Wayne 962's Garage

This board will pick up when the new Boxster book comes out. The people on PPBB aren't really tech people.

The clutch is manufactured out of similar components to your brake pads, and the operation / concept is very similar. When you're on the track, it's not uncommon for the pads to heat up and then lose a lot of their effectiveness. Well, the same thing can happen with clutch components. The clutch is designed to only be used a little bit at a time (low duty cycle). When you use it like that on a hill, it will heat up the disc, the pressure plate, and the flywheel, making it's effectiveness quite less.

Letting it cool off is a good thing, and it should return to normal operation when it's cool. I suppose it's possible to warp a flywheel much like you might warp brake discs when they are hot, but I haven't really heard of this happening.

Bottomline, this is normal, and would probably happen in any car. It's not good for the clutch, and it may be a clue that it's getting closer to it's end of life, but I wouldn't worry about it until it starts slipping under normal circumstances.

-Wayne

B.A.M. · 09-03-2008, 02:02 PM

Wayne, you are dead on with your evaluation. It is in fact just like overheating your brakes and then they return with heat dissapation. You are correct in assuming that the clutch probably is nearing the end of it's time as it's most likely getting thin and is more succeptible to the heat of constant use. Thanks from all of us for your valued input
Tom Greene
Bamsport

Zeke · 09-03-2008, 02:44 PM

Wayne, thanks for your information. I have had many, many cars over the years and most were sticks. I've never smoked a clutch on any including the Corvettes I drove as a young driver (you can assume I did a lot of drag racing, which I did). I did see a couple to the end of their life, but once they slipped, they never came back. I was able to adjust the linkage on a couple more that were simply not working well when I got the car. I musta had a dozen VW's in addition to the 'Merican Iron.

When you say "
Bottomline, this is normal, and would probably happen in any car, I haven't had the same experience.

So, what still puzzles me is the fact that I was able to start and start again and again with no symptoms until I got into 4th. Now I fully well know the torque forces on the clutch disc increase as the mechanical advantage decreases in each successive higher gear. I'm still skeptical about the the episode. But, yes, in the long run, I'm sure the disc is in it's latter days.

As I said, in the old days, if you glazed a clutch disc and blued the pressure plate, you needed to replace them. They were never the same chattering and so forth. So, you're telling me that the modern day Sachs will fade like a brake pad and recover?

Hard for an old man to digest.

One more point: using the brake example, the hot pads lose their effectiveness, but at the same time the fluid might boil. I think we can assume the boiling fluid does not do the job and the effect is the same, soft pedal. Someone on the PPBB (Porsche Pete's Boxster BBS, for the unlikelihood that anyone here doesn't know) suggested that my clutch hydraulic fluid got that hot. So far I'm not convinced. That would seem to have the opposite effect than that of slipping, i.e., hard shifting.

The people on PPBB aren't really tech people. There used to be several. They told of how you could hack the computer to get the dash display to read all the readouts that were possible only if you ordered that option. The option was on one of the stalks, I don't remember which. They used a rocker switch on the dash. Pretty techie to me.

I hope that's in the book.