Leaky Clutch

rambog · 10-29-2007, 02:27 PM

This morning, I got into my 944 only to find the clutch pedal depressed all the way to the floor. Also, there was fluid leaking from under the car.

Upon my return from work, I jacked the car up and took the picture attached. I had someone lift up the clutch pedal and press it back down. After a couple of iterations, I noted fluid leaking from clutch inspection hole. Please note: There was no rubber plug in the clutch inspection hole. I bought this car about 60 days ago so I don't know how long the rubber plug has been missing.

Any ideas on what could be wrong? Could the plug missing cause this? Will ordering a simple plug and refilling the fluid possibly fix the problem? (I should be so lucky).

Another point possibly worthy of note is the position of the slave cylinder piston end (from looking inside the inspection hole) remains the same whether I have the clutch pedal all the way up or down. Does anyone know what the spec says should be the distance between the slave cylinder piston end and the edge of the inspection hole?

Techno Duck · Techno Duck's Garage

Looks like the slave cylinder is leaking. You can buy a rebuild kit or simply replace it.

ColoradoSteve · ColoradoSteve's Garage

Replace the slave cylinder; it's easy to do but you probably should do the master as well which is a little more difficult. I had the same thing happen and replaced both cylinders, the clutch works great now.

adrian1 · 10-29-2007, 06:00 PM

Slave Cylinder needs to be replaced.their like $55 on ebay new and the oem.

2Tight · 10-29-2007, 06:17 PM

If you do both slave and master, it's a good time to replace the hard line between them as well as the blue hose from the reservoir to the master.

rambog · 11-01-2007, 07:56 AM

I have ordered the slave clutch cylinder and the tube that connects to, I think, the master. I only elected to replace the slave becuase of constraints on my finances and ability to work on cars. I am only fixing what is broke. Thank you all for quickly pointing out the issue is with the slave clutch cylinder.

My question is "are there any special gotchas or key things I need to know on how to replace the slave clutch cylinder"? While I'd love a step by step, I am simply looking for any special tricks or things that I would not be able to figure out as a first timer doing this. Thanks.

flash968 · 11-01-2007, 08:00 AM

hydraulic clutch rubber components are only intended to last 5 years - 8 years is a stretch - MANY of these cars are on original components, and are destined to fail - it is only a matter of time - they fail from the inside out, and issues with them are not visible from the outside

when changing one rubber component in a hydraulic system, you should change all of the rubber components in that system, if they are more than 2 years old - failure to do this FREQUENTLY results in failure of one or more of the remaining components, due to the increased pressure then being exerted on those components

as a service item, it is imperative that you completely flush the entire hydraulic system at least every 2 years

onZedge · 11-01-2007, 08:00 AM

Clutch master info. I know you're not replacing it, but you should at least read it:

http://www.clarks-garage.com/shop-manual/clutch-04.htm

Clutch slave replacement and bleeding:

http://www.clarks-garage.com/shop-manual/clutch-02.htm

martin944 · 11-01-2007, 12:05 PM

Is there a cap for the clutch inspection hole?

Eldorado · 11-01-2007, 12:18 PM

there should be, but my car is without it...

and I think it's foolish to replace just the slave.. but that's just my opinion... you'll get to do the master too in the next little while so you'll know what that job is like... I would have just replaced both... if you cant afford a $60 part, you shouldn't buy a porsche

flash968 · 11-01-2007, 12:28 PM

i have to agree - this is one of the least expensive jobs on this car - if it is a financial burden, it's probably the wrong car to own

earlr85944 · 11-01-2007, 12:29 PM

after you replace them, power bleed the system....

flash968 · 11-01-2007, 02:38 PM

yes - motive power bleeder is the best thing i've seen yet - cheap and easy too

theghosttanker · 11-03-2007, 08:20 PM

don't fix it! Replacing a perfectly good master cylinder is just plain silly. For all you know, the previous owner JUST did it before you bought the car. If you have to go back next week or next year and replace the master, so be it. If you replace your master now, there's a very good chance you are just wasting time and money. If you have to replace it later, it won't be any extra work; replacing the master is a different job than replacing the slave.When you replace a clutch, you replace the throwout bearing because it's a HUGE job to replace it later. The same logic doesn't apply to a slave and master cylinder.Chances are, you're just wasting time and money, and if the master does go bad later, there's no penalty.

Eldorado · 11-03-2007, 09:29 PM

except the time to do two repairs.. shipping charge.. etc...

point is, a flaw in a hydrolic system will cause flaws through the whole system because it's working harder... and if it's on the brink before you do the first repair, when you pressure that bad boy up again, it's going to fail more quickly.

the life on the two pieces is typically the same.. like wheel bearings, if you replace one side it's always best to replace the other side... unless there's premature wear due to a leaky seal or something.

it's your dime, so do what you feel comfortable with (And what you're able to).. just expect to replace that master soon..

it's an easy job, i'd do both.
look at the boot on the master cylinder (get on your back and look up behind the clutch pedal at it... if the boot looks wet at all, replace it).

Rick V · 11-04-2007, 03:43 AM

Replace both units.
The master and slave have seals in them that when replaced together, wear at the same rate. If you replace only one you will be putting extra strain on the inner seals on the older unit. It will last for a while but it will fail. If your luck is like mine it will fail when you are 500 miles from home, late, on a sunday night.
It's not that bad of a job, it is worth the piece of mind.
This is real world advice from a pro. wrench.

flash968 · 11-04-2007, 05:16 AM

agreed - the thing being overlooked here is that when the master goes, you're calling a tow truck - i don't know about anybody else, but even using the AAA card, avoiding the time on the side of the road kicking myself for being too stupid not to do it right the first time is worth a lot more than the 75 bucks for the master

besides, since you need to change the rubber line that goes from the master to the hard line anyway, you are half way there - 2 nuts and a clip and it's out

the entire job should not be more than $250 and it's less than 3 hours of time - this is not one to cheap out on - the frustration from doing so when it fails will far outweigh any ill-conceived illusion of savings

theghosttanker · 11-05-2007, 02:34 PM

I can't believe you guys. By your logic, I should go through every part on my car and replace it now because it MIGHT fail in the future. It might fail tomorrow, maybe next month, maybe next year. Maybe never, but replace it cuz somebody with no common sense about hydraulics and a "pro wrench" say MAYBE it will break. "Pro wrenches" like that are part of the reason that Porsches are so hard to afford. The pressure in the clutch system is determined by the diaphragm spring in the clutch. Unless you replace your pressure plate, you won't effect the amount of pressure the master cylinder is subjected to ONE BIT by replacing the slave. The fact that somebody says it will is a good sign that you should ignore their advice.
It IS true that I have seen master cylinders fail soon after replacing the slave. I've taken them apart and I'm pretty sure that the most common reason for this is that you have pulled dirty, gritty, contaminated old brake fluid down into the seals and check valves while bleeding the system after replacing the slave. But the vast majority of times that I've replaced slaves or masters, I have seen the other part continue to work fine, often for many years. In particular, I have usually noticed that slaves don't last as long as masters. The number of times I've seen both fail together certainly doesn't warrant a knee-jerk "replace everything OMIGOD" reaction. And the vast majority of the time, a master failure is gradual enough that you won't be stranded. hey, if I'm wrong here, what does it cost you? Nothing. If they are wrong, it costs you the time and money WASTED by replacing a perfectly good working part.
By the way, I used to be a "pro wrench" too. But it was at a regular service station, not a Porsche specialist. Replacing servicable, working parts just because they MIGHT break is a terrific way to really piss a customer off. If you are on a budget, fix stuff when it breaks.

Rick V · 11-05-2007, 03:33 PM

When I pass on advice, I pass on the advice I also follow myself. I would never replace just one unit (emergencies excluded) on my own car, and I would never recomend a customer, or fellow on a message board, to do it either.
And my credentials don't include "service station"
I'm not going to get into a pissing contest here, we have better things to do. I recomend we agree to disagree.
And I recomend you post a pic of your 240Z, I never tire of seeing those cars, they are works of art.

flash968 · 11-05-2007, 03:46 PM

i have been at this for 30 years, and spent a LOT of it in british cars, so unfortunately i do in fact know a LOT about hydraulics, as would anybody who did the same thing - weak or old seals blow - period - change one without changing the others, and the remaining weak link WILL fail

the high pressure line on the 968 is a very common failure item, to the point of me having to design a stainless braided line to replace it (sorry - nothing yet for the 944 - different fitting) - to give you an idea of just how common a problem it is, there have been over 50 of these sold in the last year

based on some very recent polling on this subject, the average is a 50% failure rate in these clutch hydraulics in less than 6 months when you fail to change all 3 components - it has been such a common thing, that many of us now joke about it (a little commiserating amongst friends)

and yes, many parts should be changed BEFORE they fail - this is not a datsun - neglect this car and it will let you know

the policy of "wait until it breaks" is why 4 out of 5 944s i see are beat up, worn out, filthy, beasts that i would never consider driving hard like they were intended to be - it is sad to see that many of them have gone to kids who generally don't have the money to keep them up, further exacerbating the problem, and accelerating their journey to the wrecking yard

but i do like the rather uncommon pleasure of seeing a clean one, and chatting with the owner

i've passed on the wisdom - what you do with it from there is up to you, but you have been warned