Clutch Pedal drops to floor (master or slave?)

[Arpegius]

So I was driving home today and my clutch pedal dropped to the floor however I could pull it back up with my foot and drive a little further. I didn't wanna drive to far in fear that is would damage my transmission. I thought maybe there was air in the lines so I tried bleeding the system.... unfortunately nothing came out of the bleeder valve, and when something finally did it was a very weak drizzle. I had my friend just keep pumping the pedal when the valve was closed, but whenever I opened it, little drizzle. Could this be a faulty master cylinder or slave cylinder or something completely different? Any help would be much appreciated. Thanks everyone.

[erik325i]

Could this be a faulty master cylinder or slave cylinder?

Yes, it could be either.

Did you check your brake fluid level? Remove your lower knee bolster and look at the master cylinder to see if it's wet/dripping fluid. Look at the slave cylinder to check for the same. Top up the brake fluid and rebleed the system. It's kind of a pain to bleed the clutch manually, but keep at it. Find which one is leaking and replace.

-Erik

[Jon325i]

I would suspect its one of a couple of things....

1) Your slave cylinder is shot, or

2) You have a lot of air trapped in the hydrualic lines of the clutch itself

If it happens to be scenario #1, just go buy a new slave cylinder - there may be rebuild seal kits out there but in my opinion a replacement is the best piece of mind approach to take.

If it happens to be scenario #2, check every hose fitting and make sure they are all seated tight with a good seal. If any of these are loose or the seal(s) are bad, this could be the source of the problem. The slave cylinder circuit is tied in with the fluid reservoir for the brake fluid.....so check around the master cylinder as well for any suspect problems. If your cars' brakes are still operating fine and only the clutch is acting up, you can rule out your master cylinder being shot.

Jon

[erik325i]

The slave cylinder circuit is tied in with the fluid reservoir for the brake fluid.....so check around the master cylinder as well for any suspect problems.

If your cars' brakes are still operating fine and only the clutch is acting up, you can rule out your master cylinder being shot.

Jon

That's not necessarily true. Sure, the clutch and brakes share the same reservoir, but the clutch has it's own master cylinder. Since the hose that feeds the fluid from the reservoir to the clutch master cylinder is on the side of the reservoir it is possible that the fluid has dropped below the line feeding the clutch, but still has enough fluid to allow use of the brakes since the brake master cylinder is directly below the reservoir. So, the master cylinder could be shot even if your brakes are still working fine.

I hope that all made sense...

-Erik

[Arpegius]

Thanks for all the great suggestions. When I look at the slave and master I don't see any leaking or dripping and my reservoir is filled to the max line and my brakes do work well. I did bleed the brakes a couple days ago and was wondering, if I let too much air in the system would it find its way in the clutch line and cause problems? If on of them is fouled I'm hoping it is only the slave because it seems easier to replace and a heck-of-a-lot cheaper than the master.

[erik325i]

I did bleed the brakes a couple days ago

So, you bled your brakes before your clutch started acting up?

if I let too much air in the system would it find its way in the clutch line and cause problems?

Of course air in the lines would cause problems. That is exactly what you are experiencing. What do you mean "too much air in the system"? You should not be letting any air into the system.
Bleed your clutch and you will probably be fine.

-Erik

[ADEN]

HEY man dunt change the master without the slave or either way.if you change one the other will stop working sooooon.change both that's my opinion.

[jlevie]

Since the problem occurred a few days after bleeding the brakes and while driving the car, the cause isn't air in the clutch system as a result of the brake bleed. If that were the cause you'd have have the symptoms as soon as the brake bleed was completed.

If there are no leaks at the slave cylinder or in the lines, the cause of this is a failed master cylinder.

[schmidty]

HEY man dunt change the master without the slave or either way.if you change one the other will stop working sooooon.change both that's my opinion.

ditto

[Arpegius]

from what all of you have said, it sounds to be like a bad master cyl. would a bad master also make it so very little to nothing would come out of the bleeder valve on the slave? I might just end up replacing both while I'm down there. Thanks again for all the help.

[jlevie]

A bad master won't generate the pressure necessary to operate the slave and may not push enough fluid to the slave for a pedal bleed. That pretty well matches up with your symptoms.

The usual cause of a clutch or brake system failure is corrosion from accumulation of moisture in the brake/clutch fluid. Which in turn is cause by a failure to change the fluid no less often than every two years. That being the case, if one part has failed, there's a good chance that the other will soon. So replace both the master and slave at the same time. And in the future flush the systems every other year.

[sticksdaman]

much truth in this thread.... im finding this out the hard way

bump for some great info