Hi, got one here's the frying my noodle a bit.
2dr RR with 4 speed lt95 box, mated to a Perkins 4236 - apparently a professional conversion; from what I see looks good.

After about a year from getting the rr, the Clutch pedal went to floor without any clutch depression.
Went underneath and saw a leak from the slave cylinder, so replaced it with a Lockheed delphi original; all seemed ok.

5 months later, clutch pedal again goes flat to floor. See leak again underneath - checked master cylinder, no leaks from there (checked inside too), and got pressure, so replaced slave cylinder again thinking I was just a tad unlucky with the lockheed again so went for a non lockheed one in case.

Just over a week later - clutch pedal to the floor.
I think it can't possibly be another slave cylinder, so I go to replace the master cylinder and yet again find the slave has been leaking.

Just to get the rr back home, I put the old slave on and get back.

The clutch doesn't slip but the bite is high.
I noticed when looking in the manual at replacing the master cylinder that there where several adjustments to be made on the clutch pedal when replacing the master.
I took the rubber boot of the slave cylinder I took off and noticed there was no circlip to prevent the piston from being pushed out of the end - just a smooth bore.

So I've got two theories on the cause of this :

1. As the clutch has worn, the slave is having to extend the piston out further.
Due to this being an engine conversion, the distance between the clutch (Standard V8 clutch) and the clutch release arm may be further than on a normal V8, so when the clutch gets worn enough it pops the piston seal out the end enough to allow a fluid leak.
If it was this, I could image grinding some metal off the slaves mounting lugs to push it further into the bell housing.


2. Perhaps the clutch pedal adjustments are there to prevent the slave piston going too far down the bore by stop adjustment on the pedal, and this is not properly adjusted.
If it was this, then I guess yet another - ahhggg - slave cylinder and have lots of fun adjusting the pedal, followed by a new clutch...

Any experience or thoughts on this one would be greatly appreciated.

cheers

Ive got a 71 RRC its not my every day drive but in the time ive had it bout 6-7 years its done Europe twice and plenty of offroading in that time its had a new clutch ,two slave cylinders ,and two clutch master cylinders plus a brake master cylinder , when the clutch went their was no slipping it just went , thing is when i got the plate out it still looked pretty good im running a LT 95 box to a pug 505 diesel, I think because of the engine+gearbox set up im only going to get 50 percent of the wear out of the clutch as you normaly would and for the slave / master cylinders i think mine are working to their limits from the off .

Thanks Mad Frank. Interesting you got no clutch slip, must have been real nice not getting any warning apart from the clutch bite.
The clutch - apart from high bite - is fine, and the last slave cylinder only lasted about a week.

I could just replace the clutch but I'd like to get this sorted so whatever the wear in the clutch it doesn't cause the slave cylinder to fail.

I know this dont sound good but i think your sooner or later goin to have the same prob as i did . no warning and no clutch , the other thing you could try is to extend the rod between the slave cylinder and the clutch fork .

Will end up replacing clutch, but also want to get this sorted so regardless of the wear of the clutch, don't end up with a knackered slave cylinder.
Did think about extending the rod - or rather having one machined. The end that sits in the clutch fork goes into a ball with a fine pin on the end - can't just grab a nice bit of rod and cut to size.

Thought also about shaving off the depth of the bolt hole lugs on the slave cylinder - probably take off about 6mm - so it sits further into the bell housing. I would guess the difference between a new and worn clutch isn't that huge, so it should be enough to prevent the piston popping out the end.

Just wish they'd put a groove and circlip in the end of the slave bore to begin with...

cant understand the circlip thing myself , should be easy enough to extend the rod , cut it towards the fork end and weld a bit of bar in .

What I meant was where there's a groove cut on the inside of the slave cylinder bore right at the end with a inner circlip sitting in it - then the piston can't travel past the circlip.
Get what you mean about cutting the bar closer to the fork and welding some spacer rod between - sounds like a good approach, cheers.

suppose you could put a circlip in to solve the slave cylinder prob , but you wont get the clutch to disengage if the rod isnt moveing far enough forward

I was meaning it would have been nice if it came like that - I wouldn't do the mod to the slave cylinder - you only end up replacing them again.
I'm pretty much sold on the idea of extending the push rod, which should also give me a bit of breathing space with replacing the clutch.

Now I'm looking at the clutch replacement job.
When I was stripping out the interior and rust treating the floor pan, I noticed that the front floor plan/gearbox tunnel had been welded on.

I took it that the best/quickest option, from what I've read, was to do an engine removal job to replace the clutch.

So I'm looking at the upper bell housing bolts thinking they're gonna be fun - I'm going to do a dry-run this weekend on the bolts to see if it looks feasible for me to do it. Also - time allowing - do what you've suggested this weekend and sort out the pushrod extension.

Apart from that, my main concern is clearance of the front of the perkins 4236 to the very front box/cross member - as in will I have enough space to pull the engine clear of the spigot shaft...So I'm going to do a hunt for any info as to how far the spigot protrudes or I guess how fat a clutch plate is + the spigot bearing depth.

Never touched a perkin,s so dont know how you,ll get on . when the clutch went on mine I had,nt got the use of my left arm , so it went to my mates garage . he took the engine out left the box in , no probs till he came to put the engine back in ,,, just could,nt get them to line up after a struggle he did it, but said never again . after having to change the box myself i think if i had to do the clutch again i,d drop the box from underneath and leave the engine alone .

I've looked at it and the least pain - in this case - appears to be the engine out option.
The engine's basically tall and narrow so access down the sides isn't too bad, three bolts on the exhaust down pipe to manifold, now dripping in WD40.

But I'm going to make sure that gearbox is solidly supported and locked in place - wood block wedge it in the tunnel if necessary - so it doesn't move at all and in theory make the re-joining go smoother...

Best of luck bud let me know how you get on.

Over the weekend looked at extending the push rod and realised if I attempted to weld with the plastic retaining clip in place/rubber boot would soon get pretty messy and wouldn't get all that back onto the rod once it had been welded.
So got the piston out of the old slave and - carefully - chopped that up and tried that but all it depress the clutch permanently when the slave was bolted up, so that's out the window. When I get chance after fitting the clutch will get a custom push rod machined.

Got back from work yesterday and got all the bell housing nuts off bar two of the sides to hold it in place for now. Exhaust disconnected on downpipe, engine mounts all unbolted - tonight it's front rad out and steering pump off engine...

Managed those top two b***rd bellhousing nuts using a selection of 3/8 drive extensions, a wobble drive and universal drive.

Also ordered a load leveller for the engine crane to help with alignment stuff.

where you to evey?

Got rained out yesterday after work, only got to get a few pipes off. This evening the thunder/monsoon didn't start for about an hour, so got the power steering pump off, got the radiator hoses disconnected on the engine side. and the grill and front cover in front of the radiator, just two of the upper bolts left for the radiator and it'll lift out.

By the way, I was looking through the original workshop manual and it showed reconditioning the slave cylinder - guess what was there on the diagram - a circlip!!! So even the genuine lockheed part now a days is too stingy to put in a circlip, tight gits.

Along with the load leveller I got myself a 'generic' clutch alignment tool ( F028 Clutch Alignment )
Weird thing - plastic with cones expaning collets, I've used in the past proper metal kits with a mandrel but couldn't stretch to it this time, so got one of these for about a tenner.
I say weird because from what I read of the instructions, it doesn't use the spigot bearing to align the driven plate but instead uses the inside of the pressure plate spring fins, so you do the alignment off the flywheel just using the driven plate and pressure plate. Think I might be a bit out of date but am a little bit sceptical - we'll see.

Cranes coming on friday so saturday is the day for the engine out, though looking at the forecast will probably also need a snorkel.

Ermm never used one of them clutch a ma thingy things being an old pro ive always gone by eye

I'm too dammned paronoid not to use a ma thingy.
The gadgets give me a false sense of well being/preparation/nout can possibly go wrong...
Well it may be plastic and a bit wierd, but it did the job and the clutch is on and engine back in, too knackered to do all the other fiddly bits like the rad but I'll do that tomorrow.

That load leveller ma thingy came in very useful - apart from the engine chain mount points were too far apart, so I ended up drilling a hole part way along the beam and putting a long bolt through to shorten the distance between the chains.

Realised from the casting above the water pump that it's a 'Milner Conversion'. Great, lovely, they kindly did there own verson of a release bearing which curiously is somewhat longer - practically double the length - of the standard, and not apearing as a quick fix to fabicate up with a new bearing, so ended up packing it with grease and putting it back in again. Didn't make it dammned long enough though did they, otherwise I wouldn't have to think about a machined slave push rod.

Oh - and I was going to replace the spigot bush at the same time, but guess what was also there own version of **** - it looks like they've just drilled it out of the flywheel, so again that got some grease and was left well alone - may both of these milner version items not need attention for ever after - ahmen.

Anyway, getting the engine back on the gearbox wasn't too bad with a combination of said modified levely ma thingy, jack under engine to provide a touch of rotation and a mate turning the engine pully to persuade the clutch splines.

By the way, this has actually been a bit easier than when I last changed a clutch on a mkII ZX turbo diesel, I didn't think it would be.

Hmm well done that man i know where to come when mine packs up next time ,

madfrank said:

Hmm well done that man i know where to come when mine packs up next time ,

Click to expand...

Wot - when it packs up on a mkII ZX turbo diesel, I'll be out, very out - out of the god dammned country - those 'machines' make me curse, curl up in a small dark cupboard and laugh hysterically (The kind of hysteria you got when we had mental institutions, instead of the 'community')...

Cheers for the suggestions, good to have someone to bounce ideas off.