no clutch pressure

[srteach]

1999 4x4 XLT manual with a 4.0 non OHV
Very cold this morning when I got in the truck. Put my foot on the clutch and it went to the floor with no resistance. When I pump the pedal rapidly and repeatedly I get enough pressure to (mostly, not entirely) release the clutch. Clutch reservoir is full. Even after the engine and weather warmed up, same story.

Master or slave cylinder? Something else? Does anyone have any ideas?

 

[dogboy]

How cold is very cold? Below freezing I'm assuming?

I know brake fluid (should be whats in your clutch lines) will obsorb moisture. Think that the moisture in the fluid, froze?

That would be my first and only guess.

 

[Hahnsb2]

Leak somewhere, likely your slave.

 

[srteach]

sub zero, no external leaks, and no fluid loss.

Thanks for the thought, Dogboy, I will replace all the fluid (and accumulated water, if any).

 

[woodyedmiston]

Clutch Master

My thought would be the clutch master. It sounds like fluid is going past the piston internally.

 

[Hahnsb2]

sub zero, no external leaks, and no fluid loss.

Thanks for the thought, Dogboy, I will replace all the fluid (and accumulated water, if any).

Yes there is, why else would your clutch have no pressure? It takes a TINY amount of air in the clutch to fawk it up.

 

[Stranger ranger]

if its leaking your not gonna see it most likely due to the fact it will be inside the bell housing.

 

[woodyedmiston]

Hahnsb2 - don't be a smart aleck - you guys are talking about leaks. The "leak" could be inside the piston bore, past the rubber, necessitating a replacement if not rebuild of the uniit - in other words it's worn out. It would not leak externally. Air does not have to be a factor. If the rubber was getting hard to begin with - the lower temp would make it less able to hold pressure.

 

[kkjb4x4.0]

Leak somewhere, likely your slave.

+1

 

[rickcdewitt]

shouldn't this be in the tranny section?

 

[srteach]

found the problem

I took it to the garage, and disconnected the clutch line. Got a rock solid pedal.

I dropped the M5D trans and replaced the slave cylinder. Bell housing was dry inside and no sign of leaks. What a pain in the ass with a 4x4.

Now I have enough pedal to release the clutch mostly (not entirely). Must have been an internal leak. Now to correctly bleed the system...

 

[fastpakr]

No pressure and no external fluid leak means master cylinder, not slave.