Thanks! Here goes.. sorry, it's a bit long-winded, but I don't know of any short way to give you all the facts.
I have a '92 Patrol, Diesel, 4.2. The problem I’m having is, when I first start it up the clutch is loose with lots of free play at the top of the pedal, and the clutch engages about ½ inch off the floor, and really quickly and sharp. While driving, the clutch pedal will get harder with no (apparent) free play (it’s too hard for any noticeable free play), and the point of engagement changes to mid-way in the pedal release, and lots smoother. Then later it will get a bit looser again, then back to harder. When the clutch pedal is hard, if you get your toe under the pedal and lift it up past ‘normal’ release, it goes back to being really loose again. Then it works it way back to being hard. It’s been cooler the last couple of days and it’s been not as bad (as opposed to last week when it was over 40 and it was playing up quite badly). It's got me (not surprisingly) and the mechanic (surprisingly) stumped as to what could be causing these problems. As you can imagine I’m a bit miffed as I’ve spent over $1400 and it’s not working properly. bad-words
Some background to this, I initially had a problem on 31 Dec (low fluid in master reservoir, clutch was not engaging cleanly and really close to the floor; and there was fluid visible on the slave and hose). I took it to a mechanic who recommended replacing the slave cylinder. He replaced the slave, but also ended up having to replace the master cylinder as well, as the clutch pedal went straight to the floor after they bled everything. (Personally I think they stuffed the master cylinder when they bled it but how can I prove that…) Anyways, I had ongoing problems for the next few days after this work was done - the clutch was slipping and the point of engagement would get progressively higher every time I changed gears; on two occasions the clutch wouldn't work at all; that is I could push the pedal in and put it in gear, but on letting the pedal out it wouldn't engage. The first time I had it towed back to the mechanic, who adjusted the clutch (under the dash). Over the next couple of days I was still having the same problems with slipping and engagement, and then the clutch failed again. The mechanic's suggestion was to replace the clutch plate. When the clutch failed on the second occasion, I had it towed to the other side of town to a mechanic that I trust. (I was beginning to feel like the first mechanic was just trying to help me spend money I didn't have). When they took the patrol off the tow truck the clutch was working again!!! This mechanic looked it over, and replaced the new master cylinder as it was faulty, and adjusted the clutch but I was only able to drive it for a couple days. The clutch kept slipping, changing point of engagement, and not engaging as before. I relented and had the clutch plate replaced (clutch kit), but am having the engagement and clutch pedal problems as mentioned at the beginning.
Any ideas, other than driving it off a cliff?? ?
Thanks! Your help and advice is very much appreciated!
My thoughts:
It seems youve tried everything that "would" normally be on the trial and error list of things to do.....
New master & slave cylinders
Bled the system
adjusted the throw
replaced the clutch plate ( clutch kit ) ---> I assume the pressure plate aswell ???? Yes / No ???
Yet the same "symptons" are re-appearing
So what else can it be ............
:insert scratching head icon:
Dumb Queston time........ this model has the vacume assisted clutch fitted ......... yes???
A simple leak could be the problem....check it first ........ fingers crossed !
In the past I've come across similar problems that you have described but the fixes you have had done should have had an effect on the problem in some way be it dramatic or minor...... so obviously the problem must be either a nonrelated issue or parts of the prior work havent been done either correctly or not at all....
Next step is to go back and double check the work that has been done, are you positive that the "new parts", being master and slave cylinders, are actually new and not just sandblasted, honed out with a bit of hand held emery paper, had a new rubber fitted and then the hole lot refitted ( & yes Ive seen that done before by a so called reptual company ).
The same would apply to the clutch kit, its obviously a tad harder to check but in this case it would be worth it..... was a new kit installed or was it simply "looked at" and left as is ???
IF....... and this is asuming that all the above work has been done & done correctly ..... if theres still a problem then we need to search further along the system chain.
bad news time......
For starters I'd suggest pulling the motor out.....ok ok that seems a tad major but in this case its a diesel and removal is simple and should only take an hour or so, it will give you heaps of room to thoroughly check everything I'm going to suggest as to posiable causes..... but before you start..... check that the gearbox bolts to engine are actualy tight .... dont laugh its happened before
..... guilty 
phucken phone kept distracting me at the time.and one other little left field check to do before the big unbolting.... get the GF or mate to operate the clutch ......have a gander that the rubber hose that runs from the master cylinder to the connector on the firewall ..... are ther any bulges ..... if so replace it and test drive it before pulling the motor
Asuming we still have the same dramas ......motor out time
Possibility 1
..... clutch & pressure plate.....The fingers on the pressure plate should all be at an equal level or height , if one or more of the fingers is sitting higher than the rest then its stuffed ...... this will be visable once the motor is removed and you shouldnt need to remove the clutchpak from the back of the motor in order to see if there is and variation...... there will be a slight waver in the fingers but no more than a milimetre...... if one or more of the fingers is sitting say 3mm further away from the rest then she's history.
now remove the pressure plate from the back of the motor and check the clutch plate itself.....
Look for score marks .... these may suggest that there is either some dammge or unwanted bits are floating around inside the clutch pak itself
Is it flat on the friction areas ...... A clutch plate that has been dropped or has a damaged edge will cause an engagement or draging issue.
Is the clutch plate sliding smoothly along the splines of the front input shaft of the gearbox...... a rusty front shaft ( common with vehicles that are dealing with water on a regular basis : = 4x4's
) ..... a few swipes with the wire brush and a fine smear of grease should fix it asap if it drags or is stiff to move along the shaft.Possibility 2
Jump into the engine bay and get GF or mate to opperate the clutch pedel inside the rig while you have both feet placed firmly on the thrust bearing and are pushing towards the gearbox.
The GF or mate should easilly move your feet back n forth as the push/release the clutch......
Is the thrust bearing carrier moving along the snout smoothly..... again check for rust/grit/mud buildup.... and again hit it with the wire brush and grease to get that thing working sweetly...... also while we're in that area... have a close look at the actual snout, these are often a thinly cast item and are prone to breaking away ...... a broken snout can cause the clutch to drag/slip/alter the engagement heights/give dificulty in engaging gears/ give dificulty in disengaging geas.
possibility 3
this is where we start clutching @ straws......
The clutch fork......... closely inspect it for cracks, its rare but not impossiable and I have seen em with stress fractures .... basically what happens is that once they are cracked then they just get weaker and weaker as they are used each time. This to me seems like a posibility with the symptons you've descibed.
If ya still not sure the wack one end in a vise and place a shifter on the other end and "flex" it in the vise to check for stress cracks.
Now with the clutch fork out its time to check a couple of other bits that are now visiable ( one bit should be laying on the shed floor )...... the rod that lives between the slave cylinder and clutch fork...... give it the same treatment as you gave the fork .... if its bent or it flexes easilly its trashcan time
also have a look at the "ball" that the fork hinges off of ( its screwed into the bellhousing ) ...... if its broken away it could well be part of the problem.... a simple weld will fix it better than new
The bellhousing ......... this is our last straw
Again stress fractures checking time....... I've got a bellhousing here that is cracked nearly all the way around, it came out from behind a chev and had given the owner grief for months and he'd replaced damn near everything in trying to solve his clutch dramas..... every time the clutch was pushed the bellhousing crack opened up a little and caused all sorts of dramas similar to yours......... phucking rare problem just the same.
If everythings workin as it should then its time to chuck the donk back in
and bolt er all back up ..... re bleed the clutch an test drive
Still got the problem ??????
If so its time to spend some upside time under the dash
This area of the clutch system is a simple one and really there aint a lot to go wrong .......................... but it does from time to time....old cars tend have these weird problems....... so do us old blokes come to think of it
The main hinge pin that runs through the top of the actual clutch pedel can wear significantly over time, mine has a high tensile bolt fitted as a result and I drilled out the oval hole that had worn its way in so it was nice n round again.
Also while ya laying on ya back have a close look at the "pushrod" between the clutch pedel arm and the master cylinder, one end has a saddle and pin setup attatching it to the clutch pedel arm...again drill and replace the pin and check the rod for bends & softness, replace it if its a weakling.
These last two suggestions are really not relevant to your problem but with the age of the vehicle comming into consideration they will be well worn and will be responsible for a large amount of adjustment loss at the other end of the system......... belive it or not but a full clutch pedel stroke can be gained from re- pinning and drilling out the worn areas, well worth it considering it takes around an hour to do it !
Other than what I've listed I'm fresh out of suggestion......
NEXT !!!!!!
Kingy
