Clutch pedal mystery

[hoover]

Last month I stored my car for a few weeks. When I decided to use it again, I found the clutch pedal was fully depressed, touching the floor.
I managed to pull the pedal back to the normal position and the clutch and pedal worked a usual. I can’t imagine what caused this event. Any thoughts please ?

[Zuffenwerker]

Sounds like a failing master or slave

[Michigan944]

Originally Posted by hoover

Last month I stored my car for a few weeks. When I decided to use it again, I found the clutch pedal was fully depressed, touching the floor.
I managed to pull the pedal back to the normal position and the clutch and pedal worked a usual. I can’t imagine what caused this event. Any thoughts please ?

When you pulled up on the pedal did it "pop" back to the up position? If you've got air in the lines to the slave or master it will do that. Happened on mine a while back, but the seals in the slave were so shot that as soon as I tapped the pedal it snapped straight to the floor.

I agree with Zuffenwerker though. Most likely a failing master or slave cylinder with some air in your lines.

[hoover]

Thanks for replies. Yes the pedal did pop back into position. Looks like I need to bleed the system and renew the fluid.

[Monkey Wrench]

the clutch slave cylinder might have a bad rubber seal. I'm sure Porsche will recommend entire cylinder replacement if it leaks, If you can get the seals you might be able to hone/polish the cylinder and replace the seals. I haven't tried but maybe a local hydraulics repair shop could have them. maybe others here have a line on just the rubber seals.

If its lke the earlier 944
s the clutch and slave cylinder are shared so "bleeding" would mean braking system too.
you cna change the fluid in the reservoir with a syringe to get it out and refill. that's not as good as bleeding but slightly better than doing nothing at all. the fluid does circulate somewhat but any water wants to find the low points, the calipers and slave cyl.

[hoover]

Thanks for that reply, sorry it’s a late acknowledgement!

[Monkey Wrench]

if the clutch slave fails you'll probably note that it's wet with fluid or maybe see a pool under the car. If the master leaks it may run under the floor carpet or running down the firewall and that can rust out the floor because brake fluid eats paint.

how about slip some cardboard under the car , fill the reservoir up, and pump the clutch a bunch of times or maybe let it sit overnight. If it leaks it will become evident. if the clutch slave is wet and dripping, then you just need to replace it. if you are stuck for the car you may be able to bleed it and just check the level really often to make sure it doesn't run dry. the clutch runs dry before the braking system. If you ump the pedal with the reservoir low enough it'll pump in air and then you have to bleed it. right now if you park it for any duration even after bleeding I suspect you will loose all the fluid from a slow leak in the slave cylinder.

sometimes if the slave is leaky you can get more fluid in by pumping the pedal and the same leak where you have fluid loss may also allow it to push out the air If you just sit and pump it.

Best to bleed it properly but if I got stuck at the side of the road I'd fill the reservoir. I'd then just pump it trying to get the air out and fluid in then it'll probably work to get you home to fix it properly. that's just because pumping the pedal and accessing the cylinder's bleeder nipple might not be very easy to do at the roadside. easiest if you have a helper to pump the pedal for you and a jack and a safety block to go under to get to the nipple. have them press the pedal down , open the bleeder, close it , then tell them to lift the pedal and then repeat until you get no air, only fluid out the nipple. Don't forget that you can't run the fluid too low or it will essentially run out , if you do run it dry, you have to start over.

if they lift the pedal before you re-close the nipple, then it may draw air in so try to time them by giving commands ( up down etc)..

only open the nipple enough to let fluid come out then close it as you see them running out of travel but while there is still pressure and then that way, there is no chance for air to feed back.

in the beginning with the slave full of air you may not see fluid until you get the air out. If you have to you can crack a line open a little at the line connection to the slave cylinder and bleed it from there first.. if the system is full of air you can have it so the helper is pressing the pedal and since there is some air in there , it may not overcome the return spring because you can compress air. so then you see no movement.
once it's full of fluid, well you can't compress a fluid. then it will overcome the spring tension again as normal, Once you get the air out, then the clutch should work so long as it doesn't run out of fluid again.

if you find brake fluid around the firewall or under the floor mats then I'd look at replacing or rebuilding the master cylinder too. give it a good bath if you see fluid on the paint.

[hoover]

Thanks for your informative post, it will be very helpful with this issue.

[Monkey Wrench]

you can bleed the brakes without really involving yourself with the braking system if you dont let the master cylinder run dry.

the master cylinder is shared. I believe it is designed so the clutch will fail before the brakes run out of fluid and fail if the reservoir is decreasing due to a clutch leak or a braking system leak. . I think that is sort of a safety feature. Safer to loose use of the clutch than the brakes.

Some cars have an alarm or a light to tell you fluid is low. If that does not exist it can be retrofitted by adding a float switch in the reservoir from a car that has it.

If you undo the slave cylinder for the clutch then i think it will drain the reservoir but only to a certain point. If the braking system gets air in it then it will need to be bled.

Its not unusual to need a new clutch cylinder due to the seals leaking.

so long as you aren't in some sort of emergency state like where you need the car next day to go to work, I'd suggest bleeding the brakes as well to get any dirty fluid and water out.

personally I'd approach the brake bleeding at a time when I could deal with it if I happened to have trouble , for example problems with a broken or seized brake bleeder nipple. If I just have one car on the road Ill often choose a Friday night or Saturday to start in because then I have a bit more time if I have trouble. Its happened too many times where I'm trying to fix my car in time to use it to get to work on time the next day and that can cause frustration.

If brakes have not been bled you might take the time to make sure you have good wrenches that fit and check that none of the bleeder nipples are seized. If any are you can tackle that, likely you will be able to just crack each one loose and tighten it again and then you will know that you won't have that issue.

Its possible to fix a caliper with a stuck or broken nipple but easier not to create that issue.
If they are tight I like to find a good small 6 point wrench that fits and use a small hammer , a flare nut wrench may do ok..
pull the wrench and tap it with a small hammer at the same time. often a bit of shock and torque in conjunction will help you crack it loose rather than simply pulling hard and breaking it off and then cursing yourself for that. Sometimes people go just a bit too crazy when tightening up bleeder nipples or they can corrode in place. I don't see anything wrong with applying a dab of never-seize to the threads if you remove them, it might help them not get stuck next time. There is likely an official torque value if you have a torque wrench that small.
they usually have a little rubber cover to keep dirt out but they often get lost.


I think probably a lot of back yard mechanics do their own brakes and end up braking off a nipple and then have that issue to deal with. an experienced mechanic would likely be a bit more cautious having been through the situation. If you dont turn too hard, it won't snap off.

[Racerbvd]

This notoriously happens when the weather changes from warm to cold. Generally the 1st freeze will do it, at least that has been my experience.
I had them go out within days in both my 968(R.I.P.)

And my 87 944S.


The part isn't that expensive, one not replace instead of trying to rebuild it?


Pelican also carries them, and has a good How Too on the replacement. But I am sure you can get the parts locally and there is a difference between right hand drive and left hand drive.
Here is a YouTube video on changing it out.

https://youtu.be/NKuCQUbeCyA

[Monkey Wrench]

you can replace the rubber parts if you like, Im seeing that for about $40 at 944 online, some suppliers only carry the new cylinder but it's out there if you look. against about 100 or so new. , if the slave cylinder is pitted from rust Id buy a new one and same if I had to hire a mechanic I'd replace it. It is possible to hone and polish the cylinder bore.

Different people have different financial positions so some may choose to repair rather than just replace, there is that choice. It may be an option to rebuild your old one to have the part onhand for next time.

when you get right down to it , the cup seals are the part that causes the leak and it may be really cheap, depends on the source. the kit has the rubber cover to keep dirt out. That may be reusable if you are looking for the lowest cost option, or if you are as tight as a rusty screw , like me:-)

I'm sure most normal people just replace it since it's reasonably priced.

[hoover]

Thanks for taking the time to give that comprehensive advice and sorry for the delay in acknowledging your posts.