Clutch or master cylinder?

[bromel]

Today I started my 2000 Wrangler, shifted into gear. Grind. The clutch pedal feels the same as it always has, but clearly it is no longer actuating the clutch. 125k and still on the original clutch. I replaced the master/slave cylinder about 5 years ago. The reservoir is still full of fluid. Is there a world in which the master/slave failed even though the fluid hasn't leaked? Or does this look like a collapsed pressure plate? Basically, I'd like to know if it's worth spending $150 or so replacing the master/slave cylinder before dropping the transmission and replacing the clutch.

 

[macleanflood]

I'd see if the slave is pushing on the fork in the bellhousing and go from there.

-Mac

 

[TheBoogieman]

The reservoir is still full of fluid. Is there a world in which the master/slave failed even though the fluid hasn't leaked?

Mine did. My only symptom was my Jeep would lunge forward and stall while stopped at traffic lights. Just like I let the clutch out too fast.

 

[CharlesHS]

As Mac posted above; verify the slave is or is not pushing on the clutch release fork.
The clutch master cylinder or slave cylinder could by bypassing pressure internally not actuating the clutch release fork.
Remove the clutch master cylinder cover, depress the clutch pedal slowly and observe if there is liquid movement upward; this would indicate a bad O ring or lack of movement of the piston.

 

[bromel]

Thank you everyone for responding. It's looking more and more like the clutch/throw-out bearing is toast. The slave cylinder does seem to be moving the fork as I can hear movement inside the bell housing. And when I removed the master cylinder cover, the liquid did not move upward at all.

 

[outofkiszek]

^ I had a similar issue where I was unable to shift into first gear after some in town driving. Turned out to be a fried throw-out bearing. Went with the all metal National one. No issue since.

 

[TheBoogieman]

Went with the all metal National one. No issue since.

Yet.

 

[bromel]

^ I had a similar issue where I was unable to shift into first gear after some in town driving. Turned out to be a fried throw-out bearing. Went with the all metal National one. No issue since.

Which one failed? The infamous Luk "plastic" bearing?

 

[outofkiszek]

Which one failed? The infamous Luk "plastic" bearing?

The original throwout bearing failed at 115k, never installed the plastic LUK.

 

[MikekiM]

^ I had a similar issue where I was unable to shift into first gear after some in town driving. Turned out to be a fried throw-out bearing. Went with the all metal National one. No issue since.

I just replaced a National ToB that had less than 8k miles on it.

I know it's been recommended but @TheBoogieman had good insight into using the plastic ToB like what is included in the LUK clutch kit. If/when it goes the plastic doesn't do as much damage to neighboring parts.

That said, I opted to pay five times as much as the National and use a US made Mopar ToB rather than gamble on another National.