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Sudden clutch failure

Posted: Tue Dec 02, 2008 11:26 am
by cc rider
I was wondering if anyone here has some light to shed on my recent problem with my 712. I was collecting wood in the forest with a friend of mine and after making our way home, I asked if he wanted to drive the Pinz. After taking the wheel, he was having difficulty in finding the gears, but I figured this was something he would get with some prodding from me in the passenger seat. We were going downhill on a forest road and though there was a little gear grinding while he found the gears I didn't consider it too terrible. We were going no faster than about 30-40 MPH and usually slower.

After about 5 minutes of fighting the gear shift, he stopped and I took over the wheel. Now the first thing I notice is that the clutch is a lot softer than when I was driving it only 5 minutes before, and now I'm having trouble finding the gears myself! I coast downhill to the main highway and find I can shift into 1st and then 2nd gear only with difficulty. After a short distance it pops out of gear and then when I get it back into gear with the truck motionless the vehicle doesn't move at all.
Tow it home, look under the truck and nothing dripping. The clutch master cylinder is full and while I can shift the gears while the engine is running or not, no power is transmitted.

So my question is, if the clutch is crapped out, wouldn't there be more warning before it fails? Also, there are none of those horrible grinding sounds made when a transmission or gearbox typically makes in my experience when it breaks. My friend is worried that he might have done something but I really don't see him doing that much damage to the drivetrain in only 5 minutes. That it failed while he was driving I'm chalking up to coincidence.

The car has been running great until this incident and still seems to run well now, except that there is no power getting to the wheels. Is there some little spring or whatever that fails that could cause this to happen. I just want to make sure all the little things are addressed before I go deeper into this problem and have to remove the clutch.

Chris

Posted: Tue Dec 02, 2008 1:32 pm
by ScottishPinz
Check the high/low selector is not in neutral first

Posted: Tue Dec 02, 2008 1:35 pm
by Jim LaGuardia
The answer is simple, the disk failed. Get a new disk and pressure plate.
When the disk gets worn too thin it will fragment. Pull the inspection cover from the floor and remove the cover on the bell housing, you will see debris if this happened, the other type of disk failure is when the springs break on the disk hub. Don't fret, it just takes a couple of hours to change out 8)

Posted: Thu Dec 04, 2008 12:19 pm
by cc rider
Jim, are there any special tools for this job? All I got are the tools in my Pinzgauer's tool bag.

Posted: Thu Dec 04, 2008 1:00 pm
by Jim LaGuardia
Just a clutch pilot tool. You can make one , use a universal one, or use one from a BMW 7331, or early Mercedes.

Posted: Fri Dec 05, 2008 12:06 pm
by M Wehrman
When I got my 7 series clutch set from Auto Zone,it came with a pilot tool. I needed to put a few wraps of aluminum tape to bring up the end to match the Pinz's pilot,simple. Easy job.
Mark