clutch problem. suspect master cylinder...

my clutch has been slowly going to shit in my '97 and after selling my '99 i figured i might want to get it fixed.

'97, 4.0, ax-15, np231 - 142k miles

throw out bearin failed about 10k miles ago. fly wheel was replaced and the pressure plate was machined. the jeep drove good for many miles. now going into gears there is a lot of grinding, no matter how much i try to put the pedal through the floor, take my time, or try to meet the RPMs. my original thoughts pointed torwards harmonic balancers or something in the tranny, but ive been swapping back and forth between jeeps lately and the pedal is noticably softer/spongier and the clutch doesnt seem to grab as well.

i suspect the MC, am i on the right track or would you check elsewhere first?





on a side note, ive been thinking of swiching to a full synthetic tranny fluid. ive heard its almost a night and day difference. would that be something worthwhile to do?

Assuming it's not leaking, I'd guess master cylinder. I notice that on my 99 the linkage is a little simpler than the older ones, so it's not likely to be made worse by a bent pedal linkage, but you should check the pedal assembly anyway just to make sure it's all as it should be. The previous design would occasionally bend owing to a poor weld design, and this could XXXX the MC pushrod and eat the MC up pretty quickly.

I'm not sure full synthetic will be a night and day difference from premium dino oil of the correct type, but it is pretty nice, especially when it's cold. It doesn't take a very big quantity, and you can probably leave it in for the next 150 thousand miles, so why not?

edited to add, I see the forum nanny software xed out a word. It is a legitimate and clean word for displacing something sideways, and also for preparing a firearm for discharge, as well as a male of several sorts of fowl, though it does also happen to be used coarsely to designate the male member. Ah welladay. for the "xxxx" above, read cee oh cee kay.

1. Doubt the pressure plate was machined, did you mean flywheel? If the flywheel was resurfaced this could be contributing to your disengagement problem. FSM says if the flywheel's condition requires resurfacing, it is to be replaced instead. However, some have reported success with resurfaced flywheels, others have reported problems--just like yours. Other than replacing the flywheel, some have used aftermarket MC like the Howe with larger diameter pistons and that has helped.

2. I run Mobil-1 10w30 synthetic motor oil in my AX15. I wouldn't say the difference was day and night, but it shifts a hell of a lot better than it did with GL-3, especially when cold. Redline MTL 90 and Penzzoil Synchromesh are a couple alternatives. The "New and improved" synthetic gear oil from the dealership is $22 a quart--I don't recommend it, good stuff but stupid expensive.

excuse me,
the flywheel was resurfaced.
the clutch plate, pressure plate, and bearing were all replaced.

brain fart, ha.

VAhasnoWAVES said:

excuse me,
the flywheel was resurfaced.
the clutch plate, pressure plate, and bearing were all replaced.

brain fart, ha.

Click to expand...

Ok.

PM Old Man, he has done the Howe MC conversion.

First thing is to check clutch fluid level. Is it safe to assume that happenned and is good? Difficulty shifting, especially into first and reverse when stopped, indicates that the clutch isn't releasing all the way. And it will shift easliy when the engine is off. If fluid is low, the master cylinder will not push the slave cylinder all the way. If fluid is low, though, the next question becomes: Where is it going to? Got to get under and look for fluid leaks. But adding fluid can keep you good for a while longer.