Topic: clutch master cylinder

[GBJeep]

Hey Guys,

I am need of some assistance.  I have read all the posts I could find on this topic here, but my issue seems to be unique.  Heres the deal... 

First off it is a 91 YJ.  My clutch pedal has been acting up.  I have to pump it (usually twice) to be able to shift in and out of gear, because when I put it too the floor it wont let me disengage with out pumping it.  This happened a couple of months ago when it first got real cold (10*).  It went away after a day or two, although the weather stayed cold.  It returned one week ago and has not gone away.   

The fluid level has not really dropped.  I have checked it everyday this week.  The first time I checked it, it was maybe a 1/2 inch low if not less.  So it doesnt seem to be leaking fluid.

I am hoping it may just be the clutch master cylinder.  I have had the tranny out twice this year (5th gear, then output shaft) and dont want to do that again.  I believe the slave was changed 3 yrs ago, but not sure. 

Any help would be great.  This site has been most helpful!

Thanks.

[CT-Rich]

I had a similar problem awhile ago. I had replaced the clutch, master, & slave cylinders
and about 14 months later the master cylinder started leaking inside the jeep firewall.
I bought a new master cylinder and all was good for about 2 months and I had symptoms
similar to yours. The first 2 I purchased a Advance Auto Parts, the last one I got at NAPA.
I have about 4 months on this one so I'll have to wait and see.

The fluid may be leaking inside you bell housing. Do you have an external or internal
slave cylinder?

[GBJeep]

Thanks for the input.  I  believe it is an internal slave cylinder.  The only thing that confuses me is that the resivor is not low.  I guess like i said it was a pinch low, but I dont think that would cause this to happen. 

Hmmmm....

[chardrc]

when my internal slave cylinder when to hell the first few times it acted up the fluid level didn't go down (noticeable at least) but eventual it eventual it gave up all hope and drained all its fluid out. but i kinda had a special case where the problem was the clip that keeps the bleeder line connected to the slave cylinder came loose and when finally got loose enough let all the fluid come out.

[GBJeep]

Well, now that it is cold out again I am having the same problem.  Last year it just got warmer and went away.  All spring, summer and fall the clutch pedal was fine.  Well it is single digits again and I am having the same problem.  Soft clutch pedal, having to double pump to shift. 

Fluid was not low.  Am I correct to think that the master cylinder must be the bearer of this problem?  It is the exact same problem as last year, except I am actually going to do something about it this time.

Let me know your thoughts. Thanks!

[Jeffy]

Well, now that it is cold out again I am having the same problem.  Last year it just got warmer and went away.  All spring, summer and fall the clutch pedal was fine.  Well it is single digits again and I am having the same problem.  Soft clutch pedal, having to double pump to shift. 

Fluid was not low.  Am I correct to think that the master cylinder must be the bearer of this problem?  It is the exact same problem as last year, except I am actually going to do something about it this time.

Let me know your thoughts. Thanks!

I'd suspect the master.  You can check the slave by looking at the bottom of the bell housing.  There's an inspection plate there were you can look up at the clutch as well.  Although since you said it's not leaking and it 'fixed itself' for a while, I suspect it's the master.  You should be able to buy one separately from the slave still.  You'll need to drive out a roll pin to disconnect the plastic hose from the master.  Then it's two nuts on the firewall and unclip it from the pedal.

[GBJeep]

Thanks Jeffy.  I looked at some diagrams and it doesnt look too difficult.  I found a master at AutoZone for $47, so I will be picking that up.  Then I just need to find a warm place to do this.

[Jeffy]

Thanks Jeffy.  I looked at some diagrams and it doesnt look too difficult.  I found a master at AutoZone for $47, so I will be picking that up.  Then I just need to find a warm place to do this.

Shouldn't take more then 15-20 minutes to swap and bleed.  Using a vacuum gun makes it a breeze.

[DodgeMudder]

I would blead the system before replacing the master, with this only being an issue at cold temps, I would guess you have an issue with water in the system freezeing and causing your issue.  The clutch fluid is brake fluid and is hydroscopic so it absorb moisture from the air and trap it in suspension in the system, with brakes the issue is usualy heat causeing the water to steam and cause issues, but I would bet your issue is that it's freezeing and the ice in the cylinders and line is the problem.