Thread: Clutch mech hitting front propshaft in 4wd

Pictures would probably help, but the most likely reason is that one of the two cross pins transmitting torque to the clutch fork shaft is broken at one end* and about to let go, so that the lever moves further than it should - the slave cylinder will automatically adjust for this until the piston comes out!

John

* if it has been replaced by a soft bolt, this will probably be partly sheared, giving the same effect (don't ask how I know!). The pin must be hardened, a genuine part is best, although a suitable HT bolt will work in an emergency.

Cheers John youre a mine of information. I'll have a look and take pics tomorrow.
The other thing I noticed was my clutch pedal is 160mm from the floor. Being a 1969 2a shouldn't it be about 140mm?
Thinking about it, if the Pins giving way that could corelate

Originally Posted by Ozdunc

Cheers John youre a mine of information. I'll have a look and take pics tomorrow.
The other thing I noticed was my clutch pedal is 160mm from the floor. Being a 1969 2a shouldn't it be about 140mm?
Thinking about it, if the Pins giving way that could corelate

This just could be your problem - the clutch mechanism is simply being moved too far rather than its rest position being too low. A picture would show this. As far as operation goes this will simply mean the clutch release is being moved too far. If you adjust the pedal height you will also have to adjust the pushrod so there is free play.

John

Here's a pic



You can see the pushrod at the top of the picture leading down to the clevis pin connecting to the lever arm. Just to the left of the clevis, basically the left side of the bracket the clevis connects to the lever through, is a small grey wear patch. This is where the nipple is hitting.

Sorry of the quality of the pic, and the state of the under side, I really need to give it a clean.

I could actually push the pushrod back up into the slave cylinder which gave me quite a bit of free play between the piston and the pushrod when I let go. The slack was taken up when I pushed back down on the clutch. Is there meant to be a spring that keeps the pushrod in contact with the piston? Or do the fork tines just rest on the release bearing?

I'll adjust the pedal and master pushrod, then check the slave pushrod distance. Then go from there.

Could this also mean I'm just due for a new clutch plate?

To get to the 2 bolts you referred to earlier John, do I need to just drop the prop, or do I need to remove the gearbox? Haynes, and the part diagram I'm looking at are pretty unclear in that area.

Originally Posted by Ozdunc

...... Is there meant to be a spring that keeps the pushrod in contact with the piston? Or do the fork tines just rest on the release bearing?

No Spring.

I'll adjust the pedal and master pushrod, then check the slave pushrod distance. Then go from there.

Could this also mean I'm just due for a new clutch plate?

A possibility, but I would not have thought that plate wear would be enough to give this problem. There is just a possibility that the problem is due to the incorrect fitting of a Series 3 pressure plate - the Series 2a diaphragm pressure plate is the same as Series 3 except it has a spacer between the release sleeve and the fingers, held in place by three spring steel arms on the pressure plate. Should be able to see by removing the inspection cover in front of the gearlever (floor and transmission tunnel out first).

To get to the 2 bolts you referred to earlier John, do I need to just drop the prop, or do I need to remove the gearbox? Haynes, and the part diagram I'm looking at are pretty unclear in that area.

You should not need to drop the prop shaft, but you will have to remove the floor and probably the transmission tunnel. Small hands, a good light, long nose pliers and good luck help as well, as does a good clean before starting! At first look, it looks impossible, but I can confirm from experience that it is possible! The proper pins are plain steel pins with head one end and a hole for a split pin the other - there should be a washer as well. As I mentioned earlier, these are under a high load, and must be hardened - and they are so hard to change, you really don't want to do it more often than necessary.

John

I just had a look to compare mine to your picture - having problems in seeing exactly where your picture is taken from - a wider view might help (or print it so I can take it under with me!).

Having just looked at it, you may be able to get at the coupling pins from underneath by removing the prop shaft, but unless you have a lot of rusted bolts it is going to be easier without the dirt falling in your eyes. Not that it will be easy either way!

John

Not sure this will be your problem, however the mechanism in the image connects to the clutch throwout mechanism inside the bellhousing. The mechanism contains a splined shaft which engages into the fingers that press onto the throwout bearing. It is possible to reassemble the mechanism with the spline out of phase meaning the lever on the slave cylinder needs to go further down to release the pressure plate.

It could also be a case of the pressure plate not being setup correctly.

Both these problems require a gearbox out scenario, so check out all the external issues, like worn pins etc first.

I've adjusted the pedal as best I could leaving the correct play at the master cylinder. Pedal is still slightly high but without disconnecting all the reservoirs I couldn't get access to the pushrod adjuster. Still there was heaps of freeplay that could be adjusted out via the pedal stop.
Down at the slave the pushrod distance was way out of spec. But I do have a question, where do you take the measurement on the pushrod? The Haynes manual seems to be implying the distance is to the bottom of the nut when it's wound to the top of the thread. How do you know you've got the right thickness nut? It would make more sense that the measurement is to where the thread stops on the rod.
There's only one nut on the thread but 2 in the Haynes manual. The bearmach parts catalogue is showing 2 slave cylinders one with 1 nut and the other with two. Is the pushrod distance the same for both slaves? (73.4mm)