Is it master cylinder, or worse?

[trinogt]

I read through a lot of these posts about the manual trans, but it seems as though a lot of the time, people are just throwing parts at a problem, hoping to find the fix the first time around.
I am trying to avoid that, because I am very limited for time.
New clutch 10K miles ago:
I started my truck this morning to head into work, when all of a sudden the truck started moving with the clutch pedal only maybe a half inch off the floor! Startled me. I got a few block away from work, but then I could not shift gears after a red light; I pulled off the road in first gear. I got it into neutral, then played with the clutch pedal for a while, then I was able to get it into gear again, and all the way to work, even though clutch engagement point is much closer to the floor. I got home ok, and bled the system 4 times. Same problem. After bleeding, the pedal was moving too easy, but after several pumps it started to feel normal again. Bled again, weak pedal again, then normal after a few pumps. Clutch still not right, with the engagement happening just off the floor, which I guess is not as bad as not disengaging at all. Is this the master cylinder? Or, am I going to have to drop the trans now?
1998 Mazda B2500
Thanks,
Mark

 

[trinogt]

No replies yet?
Well, I went ahead and replaced the clutch master. It worked great for two days. Now this morning, clutch pedal to the floor, truck starts moving. Made it to work, opened the reservoir, all fluid gone. Topped it up after work, pumped pedal a few times, and made it home with still an early engagement point. The fluid had to go somewhere. Is it a leak in the slave? Did I waste money on a master cylinder?

 

[lepp1892]

it is probably the slave, the m50d are notorious for leaky slave cylinders.

 

[red85]

Sounds like a leaking slave to me. Pull the inspection plug out of the bell housing and check to see if there's any wetness in there.

 

[trinogt]

Well, brought it into work today and put it up on the hoist. I could see where the slave was leaking fluid. Great! I don't think it contaminated the newer clutch disc, or at least I hope. Gonna pay to hve it done since I don't have the time anymore for this stuff...

I wish the slave got replaced with the clutch last year! Advice to all: Replace any parts within bellhousing TOGETHER while you are in there!