elbeee964

Well, I've searched the postings re my clutch's softening once the engine's up to high rpm-temps.
Some of my symptoms seem common to past posts: a 'null' (no resistance) area of clutch pedal travel at the top of pedal movement, a resistance 'bump' to come all the way back out -- unless I pull it past this hang point with the back of my toe, clutch not fully disengaging during these pedal depresses, etc.

But something I haven't heard of is this choice tidbit of my (red) '93 C2: as things cool down (but with engine still running) the pedal firms back up -- and the pedal goes back to its full, firm released position.

I've pressure bled ("Power Bleeder" @ 15-20 psig) the clutch line and brakes with a liter of ATE gold. The fluid coming out was khaki-colored but not tooo bad. And now with golden fluid involved, symptoms remain unchanged.

Sooo....

Could air be hanging up in the rubber supply line that loops around to supply the slave?
Any ideas of whether this temperature-cyclic nature reflects a bleed problem, or does it sound to be a slave seal problem?
If a bleed problem, any tricks beyond pressure bleeding that will kick out that last bubble(s)?

Thoughts will be appreciated!

viperbob

Replace the slave cylinder (and clutch hose)... 95% chance that is the issue...

andrew911

dlbee- Just had slave cylinder and the hose replaced on my 1993 last month...with 23K miles on my car, this appears to be an age related issue now mileage related. Now my pedal is perfect again.

Geoffrey

The other issue is that over time, the needle bearings for the shift fork pivot rod dry out and no longer move. This wears the shift fork pivot rod and prevents it from moving freely. This will also cause the clutch pedal to be notchy and fail to return properly. No amout of bleeding or replacing the clutch master or slave cylinder will fix this problem.

Indycam

When I took my motor / clutch apart , that bearing was a bad joke . Rusty , worn , dry , nasty .　Looked like it had never seen a drop of lube in it life .

dfinnegan

Curious as to your opinion on the fix for this problem.

Geoffrey

There is an updated part that I buy which is 1/3 the price of the factory piece and is bushed rather than a bearing. Works nicely. I should have taken a picture of it as I just put it in my C2 this weekend.

andrew911

This is true, but his comment on the heat affecting the pedal was the same issue I was having- as the car got warmed up, the pedal quickly got worse...

Geoffrey

I'm not suggestion one problem or another since I'm obviously not there, only pointing out that there can be any number of issues going on.

elbeee964

Thanks guys for your input.

No one unequivical answer, but enough open discussion to push me into making a noontime order w/ pelican for a slave, a hose and some more gold ATE.
(The price of replacement is peanuts in terms of porsche-adjusted dollars.)

I'll come back with results (and possibly photos) in hand later in the week...

Update: I didn't mention before, but there isn't anything in this car's receipt pile re any previous slave replacement(s). Owner #2 installed a LWF @ 65k miles ( ...and chip, and hot film MFS, and K&N, and... and...) I'm #4 @ 95k.

JasonAndreas

Pack the bearings with Olista Longtime 3EP. Its possible to do without removing the transmission but not worth the potential complications. Its too easy to disturb the needle bearings on the far side of the bell-housing and then you're screwed.

You should add high pressure grease (Olista Longtime 3EP) to your order, which Pelican stocks and pack the receiving cup for the slave cylinder on the release fork (red arrow below) to prevent squeaks and corrosion.

f11

I find my '91 C4 clutch pressure point starts to move towards the floor as the car is warmed up, but only in summer driving. In winter driving, the pedal stays firm. But in summer, all I need to do is do a couple double-clutch down-shifts and the pressure point starts to sag. If I behave myself for a while, the pedal gets firm again. I asked about this when I first started posting here, but got no suggestions for repair.

Rod

elbeee964

Jason, that's just what I saw tonight as I check-unfastened the two slave retaining nuts and the hose to steel line connection. They all started turning, so I just took everything off and cleaned up their now-vacated neighborhood and that fork cup.
Now it's just a wait for Wed's UPS delivery.

I'd read your 'soap grease' suggestion re the receiving cup in previous postings and had that in mind when I was looking around Pelican. Unfortunately I didn't see any. I'll be using hi-temp brake grease, instead. Thoughts?

Oh, I also took someone else's post's suggestion re removing the obstructing 'overhead' airbox and 4"(?) dia orange vent line to make easier access to the slave's area. I can attest to it giving helpful elbow room!

My engine, clutch and tran are leak-free affairs, and I couldn't feel any 'crunchiness' with the clutch fork. At least, so far. The slave, however, (after it came out) did feel a little "urch-urch-urchy" (like rubber making halting progress across a wetted glass surface) as I pushed it by hand through its stroke. And I'd had that same feel out of the clutch after this last bleeding. FWIW.

JasonAndreas

Your local dealer should also have some in stock, Porsche part no. #000-043-024-00 (MSRP $16.54).

Lowering the engine and transmission a few inches will also make this job a LOT easier.

When you have the old slave cylilnder in-hand pull out the hydraulic cylinder and check the condition of the pressure seal.

elbeee964

Now THAT'S the proud Porsche-pricing I've grown so accustomed to! I'll put a call into them for some. Thanks for the p/n!

No doubt, but I don't have an appropriate lift/cradle (or knowledge!) to do that. Though I did have the neccessary socket/extension/screwdriver to remove that interfering airbox & duct.
So that's what I done did do.... [Mater channeling off]

Have it in hand now. (Took it out last night.)
Disassembly & eval sounds like a good idea. And I hope I find the worst! ie, a corroded or not true barrel... and/or hardened rubber seal(s).
So, here's to finding the worst!

Thanks, again, Jason.