Clutch to floor - master? slave? just bleed?

[fishfeet]

My clutch goes to the floor every so often right now. Not consistently.
When it happens it does so for a few minutes. After a few stalls and pushing of the pedal I can drive normally for a good while without an issue.

Of course this means I could have an issue with one of the cylinders.

I just looked at the slave and the seal between it and the bell housing seems dry. I have a lot of blow back from oik & power steering so its tough to be certain, but right at that seal it seems dry. Is this the only place I would notice a leak out of the slave?

If it is the master, how would I tell by looking? Would the leak be inside the car from the boot?

I have already purchased OEM replacements for both the master and slave since I did not know which part I needed and I wanted to fix this weekend. The shop will allow a return on the unused part(s).


Since the problem only happens in what appears to be a "cycle" (periods with an issue, periods without) does it seem reasonable that it may just need bleeding? If there is no leak how would air get into the system if it's been trouble free for 3ish years since I did a clutch swap?

I'm going to try bleeding the system using the oil can method
[ame]http://www.youtube.com/watch?v=wdf--suwqw0[/ame]
I hate the open bleeder, push pedal, close bleeder method so I'll give this a try.


I have never messed with or had to diagnose a master cylinder leak so advise appreciated.

96 328is 190k miles

[flyfishvt]

sounds more like you're low on fluid so that would lead me to start with the master. I only have experience with brake masters and once they start to go they don't "cycle". Of course the best solution is to catch it while its doing it and pull the slave and try to push in the piston by hand.

I love that video by the way. If I ever need to bleed the slave that is exactly how I'm going to do it.

Bleed your current slave and see if it takes care of it. You can always return the parts next weekend.

[fishfeet]

I forgot to mention I have checked the fluid level and it's fine. Which is another indication to me that it is not actually leaking.

[fishfeet]

So after I made this thread I bled the system. System worked great for about 2 weeks. Pedal felt more responsive too.
FYI, a cheap oil can does NOT work as shown in this video. As you press lever on the can it introduces air into the system... it is not just a stead stream of fluid. Perhaps a better quality oil can will work better...

Anyway, a few weeks later it started again, and seems a bit worse. Pedal back to the floor. It is not all of the time, but just every once in a while it'll do it for a few minute and then back to normal use.

The fluid level doesn't really look like its changing.
The slave doesn't appear to be leaking, at least not visually on the outside. I don't see any drips coming for the area.
The only thing I am not able to determine is if the master is leaking. I do not have any fluid on the inside of the car... is that the only place I'll find fluid or can it leak on the engine side as well?

I know the slave is very easy to change. I'll go ahead and swap it out, bleed, and see what happens a few weeks from now.
I've heard the master cylinder is a PITA.

Help very much appreciated.

[addnon]

Can you describe what you mean when you say the pedal is going to the floor? Is it just going limp? Or is it getting "stuck" down there when you press it down?

[fishfeet]

It gets stuck. I am able to use my foot to get it back up again, shift, and continue. Sometimes it forces me to stall out.

[Toby B]

When it gets stuck at the floor, the clutch is still hooking the motor to the trans, right?

It's the master. The cup- shaped seal relies on fluid pressure to hold a tight seal,
and it sounds like yours is either very worn or scored.

I'd do both, do it once, and never have to look at it again. If one's very worn,
the other can't be too healthy.

Change the rubber hose, too- it's cheap insurance.
Those of us who drive older cars all have tales of different ways that
hydraulic hose failures have made our lives less fun...

hth
t

[projectXe36]

Its going to be the clutch master cylinder. I had the same exact problem you are experiencing. Its not that much of a pita to swap its just an uncomfortable position. If you take out your driver seat it will be alot easier to fit under there. Good Luck

[JDStrickland]

My clutch goes to the floor every so often right now. Not consistently.
When it happens it does so for a few minutes. After a few stalls and pushing of the pedal I can drive normally for a good while without an issue.

Of course this means I could have an issue with one of the cylinders.

I just looked at the slave and the seal between it and the bell housing seems dry. I have a lot of blow back from oik & power steering so its tough to be certain, but right at that seal it seems dry. Is this the only place I would notice a leak out of the slave?

If it is the master, how would I tell by looking? Would the leak be inside the car from the boot?

I have already purchased OEM replacements for both the master and slave since I did not know which part I needed and I wanted to fix this weekend. The shop will allow a return on the unused part(s).


Since the problem only happens in what appears to be a "cycle" (periods with an issue, periods without) does it seem reasonable that it may just need bleeding? If there is no leak how would air get into the system if it's been trouble free for 3ish years since I did a clutch swap?

I'm going to try bleeding the system using the oil can method
http://www.youtube.com/watch?v=wdf--suwqw0
I hate the open bleeder, push pedal, close bleeder method so I'll give this a try.


I have never messed with or had to diagnose a master cylinder leak so advise appreciated.

96 328is 190k miles

You need a Clutch Master Cylinder.

The pedal drops to the floor and the clutch does not do clutch things. This is the master cylinder. Period. Master cylinders almost always leak internally, you will never see any outward signs of fluid. You need a clutch master cylinder.

[DB MAXX]

recommend changing both at the same time. ive done my master cylinder and its a PITA. mostly the position of how u have to get it out and in.

[fishfeet]

Thanks for the help. What makes this issue a master problem vs slave? I thought the symptoms were the same for both. Is that wrong?

I have a Bentley manual... will it be sufficient as a guide? I'll do a search for tutorials on the master change out but I'm on my phone now... any guidance or valuable links?

I swapped my clutch a few years back but can't remember if i installed a new slave at that time. Regardless, that is an easy DIY.

Sent from my Incredible using BF.com

[Pdwight]

If you did the clutch change out this job should be a cinch

[toplezz328]

i honestly just had the same exact issue your describing. changed the slave cyl did the cdv delete while i was there. Works perfect, now i don't have to worry about stalling at a red light or in traffic.

[JDStrickland]

Master Cylinders almost never leak to the outside, Slave Cylinders almost always leak to the outside.

The master pushes fluid into the slave. When the master fails, the o-rings inside allow the piston to sink without moving fluid. When the slave fails, o-rings inside allow the fluid to squirt out.

Replacing the slave is easy. A bolt and a fitting. Easy to see, easy to get to, easy job.

The master is another matter. The Bentley manual covers the job very well. It is a pain to do because of the contortions needed to fit yourself in among the pedals.

[fishfeet]

So if the master failed would it be PERMANENT failure? My issue only occurs in cycles. Works fine for a while, then it gets stuck to the floor with the clutch 'engaged'.

I've already taken my seat out and removed the panel. It will be a PITA, I can tell, but I don't want to replace it unless I have to. Save myself time and money.

I do not see any fluid around the slave, and as you mentioned JDStrickland, I should see leakage on the outside of the slave if it failed. So that would lead me to think it is the master if it can only be one of the 2. Anything else I should look at before diving in to replacing the master?

[toplezz328]

i would do what i did. just replace the slave easy to get to with car up on jacks. My car had same symptoms and its all fixed.

[robisconfusedd]

I'd replace the master and slave, just to be sure.. I had my slave cyl go out a long time ago, and I was experiencing similar symptoms, the pedal would get stuck on the floor..

[freddybeemer100]

My master blew -easy to see, fluid all over the floor, stinky crap too. I have a lot of experience with hydraulics, having owned many makes with that system.
Your seal could be allowing pressure leakage but no loss of fluid.
1. Replace both units at the same time, flush all old fluid out -- it's bad, dirty and full of air and moisture.
2. remove seat, take picture of master and return spring and pedal assy.
3. replace and lube all bushings on clutch pedal.
4. disconnect flex line under car - this will give you freedom to move the master inside so you can undo the metal flare fitting which connects to the rear line of the master.
5. use vice-grips with tape around the jaws to stop the flow of fluid at the hose outside the brake reservoir -if you keep the fluid above the hose level you can avoid bleeding the brakes. If the fluid goes below the hose level -you have to bleed the brakes. I used a pressure bleeder I made out of a garden sprayer -works great.

6. slave cyl- remove hose, two bolts, remove unit. Match up to new unit -important! Make sure the rod is engaged in detent in fork. Failure to do so will send new rod shooting into bellhousing assy resulting in ruined slave unit.

7.After getting everything back together I would bleed the system with a power bleeder, a 1/4" hose on the slave bleeder which goes into a 20 oz coke bottle screw top, half filled with clean fluid, tie bottle and drill small bleed hole in top so air can escape. crack the bleeder and allow 15 lbs pressure to push all fluid through the system. You can watch the bubbles from the side of the car looking at the suspended bottle. Tube must extend into fluid to bottom of bottle. When the bubbles stop you should be ready to go. Note: with the power bleeder full of new dot 4 you don't need to worry about running the brake master dry which would introduce air in the system.

If you do order a new master - be sure to order the fitting that sits on top of the master. This fitting attaches to the supply line coming off the brake master.
To remove the old one is a hassle. Take the new one and remove the grommet from the new master, install the fitting inside the grommet and install as a unit in new master. Use a dull piece of plastic to work the grommet into the seat. I used a cuticle cutter ( not the end with the v- blade) ask your girlfriend she has one and can show you the flat plastic end. It will seat firmly when it is in correctly.

[vizsual]

So glad that i found this post. Same thing happened to me earlier this week. Clutch peddle one day started to engage real close to the floor while pulling into school. My brake fluid light comes on intermittently, only when i turn corners or brake moderately hard. It never stays on for more then a couple seconds at a time.

Just ordered the master and slave cylinders with bleeder kit and super blue. Hopefully this will solve my problems. (Don't see any leaks from any of the cylinders yet though).