Strange clutch pedal behavior as the title suggests.

I overhauled the master and slave cylinders about 5 years ago and have had trouble free operation since then. Out of the blue this morning, I pressed the clutch pedal in and it went straight to the floor. No resistance. With the pedal down I could not even get the car in gear.

When I had this problem before, the clutch pedal was sticky but I could always engage and disengage the clutch. What has me worried is that the clutch won't even engage with the pedal stuck to the floor. Is this typical of a catastrophic failure or is there something else that could potentially be broken in the clutch housing? What has me wondering is that this failure was so sudden.

I have not had time to inspect anything yet.

It appears to be a hydraulic problem. Instead of overhauling the components I will purchase new this time around along with new hoses as well and a quality fluid.

Thanks for the replies.

 

Was there any fluid leakage? Sounds like the slave went south.

 

I did check under the car but didn't see anything on the pavement at least.

 

Most likely master or slave. Also check rubber clutch lines and "feed" line from brake fluid reservoir. If you get air in there from the brake fluid getting low and dropping below clutch line it will cause it to drop. Leak may not be noticeable under car if collecting in bay or on belly pan or master is leaking into brake booster. Others correct me if I'm wrong but usually clutch mechanical failure the clutch pedal wouldn't stick to the floor because the hydraulics would make it spring back still?

 

If the pedal is stuck to the floor, that is very likely a hydraulic and not a mechanical failure. Replace the slave and master together, as they usually fail right after each other. Two times in two different 944's I tried to replace just the slave and just the master, respectively. In both cases the other cylinder failed within 3 days. Also save yourself a headache and use a power bleeder to bleed the clutch. One person job and it takes ~2 minutes. IMHO it pays for itself the first time you use it, plus it makes bleeding brakes a breeze of a one person job as well.

Hydraulic clutches can be a pain sometimes, but it sure as hell beats a cable clutch for feel and throw consistency throughout the disc's wear life. Drove my buddy's mach1 mustang the other day and couldn't get used to the cable clutch.

 

Doug, when you bleed with a power bleeder, do you prefer to bleed wet or dry? And when you bleed the clutch, do you first bleed with the pedal up and then down, or?

I've always bled brakes/clutch using the two-person method.

 

I'd second the clutch slave going out. Happened to my 951 just like what you described and I didn't have any fluid under the car. I replaced both cylinders (since everyone says they tend to fail within the same time span) and didn't have any problems after that.

 

Im not Doug, but I'll give my two cents. I use the power bleeder dry because it keeps it clean, and I dont waste fluid. When I bleed a clutch that has air, I keep the pedal on the ground and after I bleed I pull the pedal from the floor.

 

did you replace the line between the clutch and slave last time? when i replaced mine a couple yrs ago, i did the line as well just cuz it was recommended. when i pulled it out, it had a nice groove worn in the side, apparently where it had been rubbing against something. i imagine it didn't have long before a hole developed. if you have fluid on the ground, most likely you have a hose gone bad.

 

Hicks, when you bleed a clutch that has had air in the lines, as you mention above, and close the bleed nipple, after pulling the clutch pedal off the floor, do you usually get a firm pedal right away, or, do you have to pump the pedal several/many times to "equalize" the fluid on both sides of the slave piston?

Based on the design of the slave, it's not necessary to bleed with the pedal off the floor?

Doing it your way, has this always resulted in a firm pedal? Disregarding defective master/slave cylinder(s), of course.

 

I get a firm pedal right away. So I bleed with the pedal down, top off fluid, pull pedal up, check fluid level, check pedal firmness. I also lift the *** of the car as high as I can. This is the only way Ive been able to get a real firm pedal.

 

Okay, thanks.

BTW, that's pretty high...

 

So I switched out my slave cylinder and pushed the air out with a new oil can (lever type). I got the pedal to spring back like it should and drove it around. The next morning the pedal popped down to the floor again and stuck. I pumped it with my foot but is not completely back to normal. Will it work itself back without having to bleed again?

 

No, air will not work its self out of a sealed system, thats such a wive's tail. If its soft, you have air in it and need to keep bleeding. +1 to it helping if the *** end is way up in the air. I don't own that many specialty tools, I usually get by without them but I do own a motive power bleeder, its the best tool I've ever bought actually. It paid for its self the first time I did a clutch job.