clutch failure diagnosis

[klarowny]

How far should the clutch pushrod protrude from the bellhousing/ slave cylinder joint face if all is well with clutch plate, release bearing and fork is the question, here's the history...

1986 ex MOD 90 FFR (FFS!) 12Jnad, I recently (about 1000 km) replaced the clutch, release bearing, master and  slave cylinders, mostly with the mid-price 'OE suppliers' parts from Rimmer bros.

Clutch felt/worked fine on re-assembly, if with a little more freeplay than I expected. It failed today, freeplay progressivly increasing until it wouldn't dis-engage, pedal  to the floor. I have found no leaks in either the master or slave or the line, clutch fluid at reasonable level although black, which leads me to suspect seals in the master. However, on taking off the slave and pumping the clutch the slave piston moves seemingly normally. The clutch pushrod seems to be still attached to the fork and protrudes from the slave mating surface by about 12mm (half an inch in LR speak!). I'd like to know if that is normal, so allowing me to concentrate on the hydraulics, rather than diving into the clutch, not my favourite way of spending a saturday night.

This is my first post on here so big thanks in advance for any help you can give me, the Landie is my only form of transport up here in the Sabine hills north of Rome, I get to go 'off road' every day, just to get the milk, and beer, so this is urgent...!🍻

[Tim2809]

if you clamp the flexi hose the pedal should be solid.  

black fluid does suggest seals 

have you looked in through the slave cylinder hole to see if fork punched through. 

i presume you got the lt77 gearbox. (reverse next to first gear)

[klarowny]

Thanks for response, clutch release fork is new  but I will try and check, getting a sight line is hard, I'll break out my dental mirrors. Yes, LT 77, should have specified. I will clamp the hose/block the slave tomorrow to check. My question relates to exactly this possible problem, if the fork or thrust bearing is compromised, then the amount the pushrod protrudes will be less than standard, which is???  FWIW pushrod seems engaged in the  'dimple' and moves smoothly and freely.

Thanks again for your interest.

[blowmeover]

I had this problem, the clutch fork came off its mount, I had to strip out the gearbox again. But, if I were you I would change the master for a new OEM one first, if the seals go in the slave it leaks, if it's not leaking the slave is fine. With the slave off a worn master will still be able to push the piston, clamp the hose then gently press the pedal, don't force it.

[klarowny]

Clutch now working fine, I can only think it was air. I was working solo so couldn't see any bubbles while working the slave piston  from underneath, the tea lady and chief clutch pedal depressor was off on another mission. Got a good pedal as soon as bolted up the slave. Took some care to adjust the master pushrod and pedal height to spec. Has anybody any tips on making this fiddly job any easier? Access to the locknuts is frustrating even with the pedal half depressed, I'm guessing a bit of spanner grinding is in order unless there is some magical technique I'm missing. Thanks again for help.

[Mo Murphy]

Spanner grinding is the solution.

Mo