Clutch probs in a MQ

[RMP&O]

Got my 83 MQ running real well for first time in months. Took it out for a drive, everything was fine. Get home and play around on large pile of dirt/rocks. Work the truck pretty hard on the pile of earth, finally get high centered on the top of the mound. At the same time my clutch stops working.

Pull the truck back over to the shop and crawl under it. Clutch slave cylinder is siezed. Piston is in the out position, rod looks tweaked, leaking a bit of fluid. Clutch fork the slave rod attaches to is pushed forward torwards the front of the truck. Both the slave push rod and clutch fork are stuck and won't move. Truck seems to be stuck in nuetral, I have no gears, no 4wd, nothing.

I was going to start by pulling the slave cylinder off the truck and inspect it. Anyone experienced this?? Any one got advice or ideas on what to be looking for? Any idea what would cause this? Should I just start by letting the pressure if there is any off the slave cylinder by bleeding it?? Manuals don't say anything about this prob, just stuff on clutch slippage and so forth....

Good thing it happened close to home (actually at home) insted of 50 miles out on a trail.

[V8Patrol]

clutch master and slave units .....


left hand ........ right shoulder !!!!

They are probably original and worn out, not worth rebuilding either.
When you think about how many times they have been in/out over the life of the rig it's scary !!!. I just replaced both of mine and havent had a problem since but the old unit that was fitted cost me 2 clutch paks in the process.......a costly learning experiance !

Its also not worth just replacing one part of the setup.

Also while ya at it ....... check the play in the actual clutch pedel ...... the main hinge at the top should be ok but where the rod to the master comes off of the pedel will be worn. I simply drilled it out to a larger size and fitted a pin to suit. This reduced the play in the pedel by about and inch !!

Kingy

[RMP&O]

Thanks Kingy for the reply....

you are likely right, it is original and 330,000 kilos later dead as dead can be.

Anyone got a good place to buy all new clutch parts?? Is the slave cylinder, disc, pressure plate and bearing specific to the SD33 or same in all MQ's??

[berazafi]

have you been through mud, my pressure plate was held open by mud at the ends of the fingers. that will cause the slave cylinder to push the piston to the very end and posibly jam. its noramlly caused by the top fork seal being f>>ked.

All the clutches and pressure plates are different, or at least different grades, the petrol ones are cheap, the deisel ones are expensice and the turbo diesel ones are between 400-800 dollars aus

[patrol man]

MQ clutch stuck on. sound like the slave has poped the piston out , I have seen this before due to a worn pivot pin and fork. this allows the piston to travel to far resulting in the piston poping out kicking sideways and jaming. gear box out job.good luck.

[Screwy]

I just put a big crack in the side of my clutch slave cylender, only happened after the V8 went in, but its all good now. Had the original one on there so i spose it was due for a change anyways

screwy

[berazafi]

I dont know why every one complains about gearbox removal and refit in mqs they arnt to bad. All the bolts are accessable by rattle gun, i removed mine by myself with a trolley jack in around 1hour. I refited it with a mate in around 2 hours with a engine craine throught the floor in the transmisson tunnel. the manifolds were harder to remove and replace (sd33t). Anyhow give it a go its not that bad???

[RMP&O]

not real worried about pulling the tranny, it does look simple enough. Yet, the MQ is new to me....I been working on G60's for years but the MQ is new. So any and all info is helpful. Hopefully it helps learn things without making mistakes, if you get me.

The only real concern for me is getting the clutch all aligned right, that seems tricky.

I am sourcing the parts for an entire new clutch system....all of it. Thing is though, since the tranny got to come out I am starting to think now is a good time to get a Cabstar 5spd and fit it to the truck. Especially if it will require a different clutch than the 4spd.

So here is a few more questions for anyone who can awnser them....

-If fitting a Cabstar or even a MK 5spd to the SD33 will it require the 5spd bellhousing and clutch??
-Should I expect to have to use a adaptor plate between the engine and tranny?
-Is the master cylinder and slave cylinders the same in the 5spd as the 4spd?


The Cabstar came with a 4cyl version of the SD33, ED diesel I think it is called. Basically the same engine minus a few cylinders. So this is the tranny I am after....if that helps with the qestions at all.

[V8Patrol]

The only real concern for me is getting the clutch all aligned right, that seems tricky.

There are tools availiable for that...... or make up a tool from a bit of shaft, lathe down the end so it fits snugly into a spigot bush and is around 1 1/2" long .... then lathe the remainder down to the same diameter as the splined hole in the clutch plate. Its that easy !

-If fitting MK 5spd to the SD33 will it require the 5spd bellhousing and clutch??

no. just use ya original belhousing. the clutch size may be differant to the one currently fitted .... there are about 5 differant clutch sizes available for the MQ, some of the GQ ones will fit and so will a couple of GU ones.
Sizes vary from 8" to 10.5".

-Should I expect to have to use a adaptor plate between the engine and tranny?

not if you run with the MK 5 spd box.
I'm not sure about the cabstar conversion tho .... need to have one to play with to be sure.

-Is the master cylinder and slave cylinders the same in the 5spd as the 4spd?

yes !

The Cabstar came with a 4cyl version of the SD33, ED diesel I think it is called. Basically the same engine minus a few cylinders. So this is the tranny I am after....if that helps with the qestions at all.

Not having done this conversion I wont add comment, but you could find out for us

Kingy

p/s
Personally I recon its easier to pull the motor out to do a clutch on a diesel MQ over droping the transmission.
Physically its much easier and far safer too and there is a heap more room to move compared to lying on ya back under the rig.
Time wise its quicker and you can do it all by ones self without aditional ppl annoying ya !

Hell its quicker for me to pull the chev out than the transmission to do a clutch ..... I knew I should have replaced the thrust bearing last time I did a clutch .... f#*k it

[r0ck_m0nkey]

The only real concern for me is getting the clutch all aligned right, that seems tricky.

There are tools availiable for that...... or make up a tool from a bit of shaft, lathe down the end so it fits snugly into a spigot bush and is around 1 1/2" long .... then lathe the remainder down to the same diameter as the splined hole in the clutch plate. Its that easy !

An even easier way, is find a largish bolt or anything else round that fits neatly into the spigot bearing, then about 1 1/2" from the end start wrapping insulation tape around the bolt neatly until it's the right diameter to fit the clutch plate. It's all i have ever used.

[berazafi]

my local wrecker lends them out, speak to a wreaker, most of them probably do