Clutch Jammed!

[gruntly]

Ok so i went for a test drive today to make sure all my new lift bits were working correctly. Everything was going fine, then on the way down a nice steep but smooth hill I thought Id disengage the clutch and speed roll all the way down. Halfway down with a fair bit of speed and the clutch pedal fully depressed the clutch jammed on and we came to an abrupt halt. I could not get it back in to any gear, the clutch pedal was floppy as and had no resistance and grinded at any attempt to put into reverse. This didnt change with switching between 4h, 2h, 4l etc... So were stuck miles from anywhere 2 hours before dark way up in the hills with no torch and no road to follow (bush bashed all the way in with the wife and daughter), crapping ourselves! Ended up using all my weight to crunch it into reverse and the jeep shuddered backwards for a bit. Then all was good. Clutch was engaging again, although the pedal now only feels like it has half the travel it used to before gripping (ie first half of the travel is loose, last half does all the work)

So, anyone got any ideas on what may have caused this? only thing drivetrain wise I have messed with is installing RE stainless brake lines and a SYE kit... Buggerd master cylinder? water in the lines?

[bonza]

depends what year your Jeep is to be able give a proper prognosis, but sounds like the brake pedal attachment to the actuator rod has come apart or the rod itself is broken

[Macca2801]

Gruntly,

I know its not common but there is an issue with coasting with the clutch pedal engaged(clutch dis-engaged, ie floot on the pedal)...called burst clutch.

With no clamping on the clutch disc, coasting downhill can cause the friction material on the disc to be thrown off and wedge between the disc clamping members..ie wedge the pressure plate, clutch disc and flywheel.

I hope this isnt the case, otherwise its a new clutch required despite it operating ok atm.

Matt.

[gruntly]

It's a 99 tj sport.

The clutch has been getting a flogging lately, 33's and standard ratios ain't so easy on it. 4.56's and lockers goin in on the 22nd. I'll be pissed if the clutch has come apart... More $$$

brakes were still operating fine

[Jeddo]

have you checked the master cyl for fluid?
seems like a pretty obvious first step to me.

did you pump the clutch pedal for ages (like, 50 times min)? could have been air in the line.

[gruntly]

Yeah fluid level is fine, didn't pump the clutch 50 times tho. Did pump it a fair bit. Does sound similar to what macca2801 suggested. The clutch was disengaged at the time. Being unfamiliar with cluch systems, is there any process I should follow to bleed the clutch? And if it us shagged, any recomendations on a decent replacement for offroad use?

[Macca2801]

Gruntly has your pedal height come up back to normal?

Do you have an inch or so of freeplay at the top of movement (slack before it starts to get firm)?

Where does the clutch still 'over-centre' or pop, you know where the release spot is?

Are there any fluid marks at the pushrod or at the slave cylinder?

Have you had a good look at the links and assured that everything external still looks normal?

Can you get into the bell housing at all, drain bungs, recess openings,(not familar with the TJ) but if you have any friction linings damaged then there will be mess in the bottom of the bellhousing.

Check all these out and then you can provide some good feedback as to what may be the cause.

If you wish to bleed you just need a piece of old emissions hose and some new fluid.

Fit the pipe to the bleed nipple at the slave, get someone to pump the pedal all the way up and down in quick succession three times and hold down.

You open the nipple and fluid should squeeze into the hose and then you close the nipple.

Repeat the process three times and then chaeck the fluid level in the reservoir, top up as necessary. If there are no problems, after about 6-9 cycles you should have fresh fluid and be air free in the circuit. Done.

Its unusual for the master or slave cylinder to let go and then work again, usually its terminal and they dont recover at all....pedal just stays to the floor. But stranger things can happen.

Let us know how you go with the other checks also.

Matt.

[gruntly]

Pedal travel is almost normal, but not quite. Still alittle slack for the first bit. Access to the bellhousing is goin to be difficult. Probably have to pull the starter motor to get a look. All linkages are good, no fluid loss.

Thanks for the detailed response macca, will post with the results once I find the time to pull the starter out

[TassieTJ]

you won't see anything if you pull the starter apart from the bach side of the flywheel, but it does sound like what macca said to me unless the slave or master cyl let the fluid past

[Macca2801]

Yeah mate as Jippy said pulling the starter wont hepl much, if your (un)lucky you may see some fluff from the clutch plate on the sides of the bell housing but most if any will be on the bottom. If the TJ has a recessed flywheel then you wont get any...it will still be caught in between the pressureplate and flywheel.

Matt.

[gruntly]

well then, I guess ill have to wait for another symptom to turn up... might order a clutch anyway. Probably needs a new one regardless. Any recommendations? should I be considering a non standard clutch?

[gruntly]

Kudos to Macca2810, the problem was friction material coming loose and jamming it up. Also the thrust bearing was on the way out, the flywheel was blue and the pilot bearing had detonated...