Hey all, 996TT w 69k miles, some things are expected to happen.

The other night as I stopped at a stop sign, pushed the clutch in and released to roll fwd a touch then pushed in again there was a weird sound and my clutch engagement point just went down to 1/4 inch off the floor.

I read 100s of posts on clutch slaves etc but haven't found something to address this.

Accumulator is definitely bad. I start and run the car for 30 seconds without touching clutch, then turn off and then try pressing the pedal while counting. It never goes hard. I pressed like 70 times and there is no rise in pedal pressure whatsoever (beyond 35 times the 996TT manual says it's a bad accumulator).

No pentosin overflow:
- Level in pentosin reservoir perfect.
- Rear tank fluid level is at the marks where it says COLD, when cold, and pretty close to mark saying "HOT" when hot.

Master:
No leaks around master and I rule out internal failure since the pressure holds with the pedal down. If internal leak it would give way and release pressure with the pedal down.

Slave:
No leaks I can see around slave and fluid levels as said are ok.
I bled the system by the slave cylinder unit and got a touch higher engagement point b/c there was a tiny tiny bit of air (prob old), but nowhere near the old actuation point.

Gearbox/cluth area:
I was under the car to listen when my fiance pressed the clutch:
At the first 50-60% of the clutch pedal travel, there is a creaking sound from the clutch, inside or slave I can't locate. If the pedal is pressed slowly from 0-60% clutch pedal travel, it sounds like a "tick... tick... tick" during the pedal's way down (press fast and the ticking makes is like a "creaking" sound).

At the end, when the pedal gets to the last 20% close to the floor (where the clutch disengages), I sounds like a smooth movement from inside the clutch and I can actually hear the clutch releases.

The clutch bite is excellent (no slipping whatsoever). The car doesn't really have excessive power...

The creaking sound in combination with the clutch pedal engagement point drop is unnerving.
- Can accumulator make it sound like this? It should just lose some assist right, not drop the pedal?
- Throwout bearing would make noise when rotating, yeah?
- Actual clutch actuating mechanism?
- Clutch slave somehow bad but not the usual internal slave leak, rather mechanical?? Can the shaft/rod have became misaligned?

Porsche racemechanic I know believes it's highly unlikely that the clutch fork has bent.

Ideas?
I might be SOL and have to take tranny out but I really hope not to.

 

Could pressure plate be the source and if so what would have to happen/give for the pedal engagement point to just drop?

Found this but nothing confirmed that it's the same, also as opposed to OP in the linked post my clutch creaks at the first top half of pedal travel, not by the floor when the engagement actually takes place. My clutch is silent where it releases the clutch, it's the "dead travel" of something around the slave or gearbox that creaks when I press the pedal.
https://www.6speedonline.com/forums/996-turbo-gt2/224971-annoying-clutch-creaking.html

Why would the clutch pedal just drop from a normal engagement point to just above the floor - but it still works, just low?

 

I believe the creaking( if it sounds like a door in a haunted house) when the clutch is just coming off the floor is caused by the bushings that is the pivoting point for the clutch fork. Over time they get dried out and covered in clutch dust causing slight binding resulting in the squeak. Nothing to worry about and your not alone I was told you wont hurt anything it's just annoying and when your clutch is due for replacement to address then.
Your clutch sudden drop not sure what would cause that, I assume it's probably slave related. The factory oem slave is ridiculously huge could be on its way out. Maybe someone else would know for sure, this is just my educated guess.

 

Thx for the input!

I have never heard the creak before until I started looking, may have been there all the time, I can't hear it with door closed and engine running, not even in the mornings when getting in the car and pushing the clutch to start.

The haunted house description is spot on... lol
The difference on mine though is that the creak is a the top part of pedal travel, an no creaking at the low pedal point when the clutch is releasing.

Well let's hope for some pivot and not pressure plate... I can live with the creaking. The pedal drop I still have to figure out why it happened and sort out, it doesn't feel right.

 

Congrats on the new ride, I missed that you had one. Hope it works well for you and you can get it track ready in no time.

 

Thx man, think it will be a little slower process this time around but great to be back in a tt

 

Did some further check-ups and I'm pretty sure it's the master cylinder that has an internal leak.

First nearly 50% of clutch pedal travel (from top) doesn't really do anything, there's only spring resistance and I hear some motion in the master but not really any pressure felt in the hose down by the tranny/slave (holding the hose when someone presses the pedal gives a big "aha" realization of how much theses hoses flex... I thought it would burst).

There are no leaks to be found. Fluid levels perfect. There is no change to the clutch actuation point since the drop, always the same, doesn't get better or worse.

As I see it, with a normal clutch master cylinder, there should be an internal seal at the front of the master pushrod (which I believe gave up and the pedal sank). It also fits with the sound I heard from the pedal area.

This broken seal now just lets fluid pass by when the pedal is pressed down. However, the back plate or seal of the master rod is now doing the job of moving the fluid and building pressure, which is why the clutch works consistent, but just with low pressure point. Don't know how long this back seal or backplate will be able to take the pressure so master swap is imminent.

If that does or doesn't solve the issue, I'll follow up here either way. A lot of slave cyl problems here but not too many posts on master breaking (if that's it), and as we reach higher mileages I believe this might be an issue popping up too, especially for cars doing a lot of city driving (huge amount of shifting gears).

Now, has anyone found their 996TT master cyl laying around? (I'll do GT2 slave mod later when schedule allows but now just want to get this baby on the road and see if it's the master that I think it is and not something related to the pivot arm or pressure plate down at the box.

 

So what was the solution here? its always nice when you start a thread like this and solve your problem to post the solution. I'm having the same issue, when pushing in clutch now i hear a sound, like a ticking- Clutch is original on 2002 with 58,000 miles, probably needs a new clutch.

 

Mr White did you resolve this issue?

 

The return spring by the clutch pedal was one issue easily solved.

The ticking was from the needle bearings for the pin that holds the clutch release fork. Maybe due to age or the climate or the car sitting around too much during it´s life before I had it, bc it was not due to mileage (car only had 20k miles).

There´s grease in the needle bearings and two small rubber o-rings are there to prevent the grease from being pressed out over time. Those o-rings do age though and when that happens the grease could escape over time.