earossi

I've owned my 993 for about 8 months and have put about 2500 miles on it since purchasing. The clutch in the car is a sport clutch and was replaced by the PO at the same time a light weight flywheel was fitted 20K miles ago. When I first took possession of the car, I noticed that the actuation of the clutch pedal was not very smooth with a slight "jutter" as I pushed the clutch pedal to the floor. I posted about the issue and it was recommended that I just flush the brake fluid in the system, which I did. Can't really say that it made any difference. But, in the last 1000 miles, the shudder/jutter is getting worse. I am only concerned about it since I don't know or understand what could be causing it, and am concerned that I may have clutch failure while on the road.

I did an experiment though and tried activating the clutch with the motor shut off, and though the shudder is still there......it is noticeably less than when the engine is running. So, could this be an issue with the pressure plate and throw out bearing assembly? Or, any other ideas?

Activation force is not bad but is about twice what I have on my 968 that has the stock clutch package and dual mass flywheel.

Thanks in advance for your comments.

ca993twin

I'm not an expert in this area (actually, not an expert in ANY area), but I'd also take a peek at the pedal assembly on the floor. Since we have the last cars on the planet that still have floor-mounted pedals, the assembly can be crudded up and get pretty sticky. Perhaps a real expert can speak to this, and how you can lube that assembly.

nile13

Did you flush brake system or did you actually flush the slave cylinder?

ble2011

Is it a shudder from the engine or from the pedal action? If it's from the pedal, don't discount the clutch pedal on the floor. Like ca993twin says, it can get cruddy and stick. Mine was sticking and I thought I would need to flush the slave cylinder. Luckily, I looked at the pedal assembly on the floor and it was very dirty. The rubber boot covering the clutch piston was cracked (very common problem) and allowed dirt to "adhere" to the pedal shaft. Some cleaning and a spray of white lithium grease and all is well. Here is DIY for the pedal - http://p-car.com/diy/pedal/

levtron

+1 on the cleaning and white grease as first option to try. The rubber on was ripped. A little cleaning and some white grease helped a lot.

Unfortunately that does not help solve my slipping clutch problem.. But thats a different discussion. How do you like the LWF?

earossi

I like the LWF. The engine is much faster in revving. Only problem is that you can't be sloppy in coordinating release of clutch pedal and addition of throttle, or you get an occasional embarrassing stall out of the motor. Happened a lot when I first got the car, but now only happens about once a month. It's all about technique. I've driven clutch equipped cars of all breeds for over 40 years, and this is the only one that I experience the issue with. Not enough to not have done the flywheel replacement......but, you do need to pay attention!

earossi

I bled down the master and slave cylinders.

earossi

Looks like I need to pull up the floor boards and take a look at the mechanical system. Will try to do that in the next two weeks. Thanks for the responses.

AOW162435

Ernie,
Shortly after purchasing my 993 in '05, one of the first things I did was to thoroughly flush the brake & clutch circuits with ATE Super Blue. Based on what came out of the 13 bleed nipples, it may have been the first flush since the car was built in '94...

Prior to the flush, my clutch action was buttery smooth. Immediately after doing the flush, I noticed a 'judder' or 'rubbing' feel as the pedal was depressed. This only got worse over the next few days, so I consulted with Rennlist. The thinking was that the bore seals within the old slave cylinder were used to the old fluid. By flushing that out and introducing a new fluid, the seals very likely started to swell or deform in some way.

So I installed a new slave cylinder and new rubber hose that joins the slave to the hard line. Flushed again and the action was buttery smooth again.

I've flushed the brake and clutch circuits every year since (Super Blue) and the clutch continues to feel perfect.


Andreas

Van1

My first mod/maintenance item I did within the first week of purchasing my 993 was to replace the clutch slave cylinder. Definintely smoothed things out. Not a fun thing to replace though.

nile13

Just wanted to make sure as these are two separate hydraulic contours.

I would probably look at replacing the slave. After doing visual inspection of the pedal box. But I think it's the slave as Andreas described above.