clutch master cylinder failing?

beerly

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While out for an extended highway drive today I noticed several times the clutch pedal going limp. Pushing the pedal in would disengage the clutch normally but it wouldn't catch until it was almost to the floor. there was no difficulty in shifting and after pumping the pedal, pressure would return and the pedal would firm up again. Then the pedal would operate with full pressure and travel for several minutes and randomly the pedal would go limp again. Again, pumping the pedal would return it to normal. Does this sound like a clutch master cylinder problem? I was thinking slave cylinder but everything I've read indicates that I would probably see fluid leaks. I don't see any leaks and the reservoir is full.
 

Steve-Indy

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Anything is possible...but my first thought would be that you are boiling the clutch fluid with headers and lack of shielding on the hydraulic line. Have you changed the fluid lately? It might be worth it to change fluid and bleed system before you change anything else.
 
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beerly

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That was another concern. The line runs right by the header (like an inch) but it's shielded, maybe just not enough? I have not changed the fluid since I've owned the car. What color is DOT 4 fluid? It may be burnt. Mine is kinda brownish. Thanks for the insight I'll go ahead and change the fluid and bleed. Any suggestions on protecting the line? Maybe rerouting? Better shielding?
 

Bandit3

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Hey Beerly, sorry it so long to respond, not on the computer much. Yes its the clutch master cylinder. Fairly easy to replace, I had my son do it!!! Remove right front tire inner fender panel and its right there. I forgot what the connection was under the dash, but removing the drivers seat helps, specaily if yer a lil, well you know! Connection was easy also. I seem to remember the new master came with the hose and was full of fluid. Quick disconnect to attach to transmission. Good luck
 

Viper X

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That was another concern. The line runs right by the header (like an inch) but it's shielded, maybe just not enough? I have not changed the fluid since I've owned the car. What color is DOT 4 fluid? It may be burnt. Mine is kinda brownish. Thanks for the insight I'll go ahead and change the fluid and bleed. Any suggestions on protecting the line? Maybe rerouting? Better shielding?

As above, a fluid change may solve the problelm. More and better insulation will help if you have headers, though rarely does fresh fluid boil on the street due to header heat.

.....and I have not yet seen a clutch master cylinder fail. Doesn't mean that it can't happen though. I have seen MANY clutch slave units fail.

Good luck,

Dan
 
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beerly

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Great. Thanks guys. I'll start with a fluid flush. The level in the reservoir is about 1/2 inch below the "step line" and there was some brake fluid inside the little rubber diaphragm and the fluid looks terrible. Could this indicate boiling fluid? Would a failing slave cylinder begin as a slow leak or does it just go and puke fluid out the bell housing? I drove it yesterday enough to get the engine up to operating temp and the clutch worked fine.

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NMviperguy

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Just like in brakes, since it's the same fluid is it absorbs water. When water gets absorbed it lowers the boiling point of the fluid over time, since water has a much lower boiling point than fresh fluid all the above is possible. Especially if you are in a humid climate. There should be a bleeder screw somewhere on the line just as on brakes. Use a turkey baster or similar to **** out the existing fluid, fill with fresh fluid and bleed until all your fluid is as clear as you put in from the bottle. Make sure your diaphragm is in good condition, if you aren't getting a good seal this issue will continue to happen. Hopefully it's the fluid!
 

blackvenom08

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I had a clutch master cylinder fail and during the course of doing what everyone told me to do before replacing it (fluid change, bleed the system, make sure it wasn't over heating, etc etc etc) I screwed up the syncros. Should have just trusted my gut and replaced it considering its a 100 dollar part. Ended up doing the whole clutch system in the end pretty much..Also, to answer your question, my reservoir was still full and there were no leaks when I determined it was the master.
 

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