JD 7800 clutch adjustment

[Godber]

Clutch pedal has dropped down a bit and not fully disengaging drive when applied especially when warmed up. Can you adjust these? Can't see a master cylinder anywhere but they must be hydraulic. Think I can see a cable from the pedal.
Thanks

 

[mushnt grummmble]

@green giant

I think you can adjust the clevis on the end of the cable but it might be getting ready to snap

 

[masseyfendt37]

@nztech can always help

 

[Godber]

A few weeks ago a pressure test showed that an internal seal had perished stopping the diff lock from working. Thought this could be something similar. @NZ Tech
Thanks everyone.

 

[NZ Tech]

Sump valve oring... usually.. Its not a common problem and is easier to get to on a 7810. Ill dig up some info.

Also are you certain the Forward clutch hasn't failed. Black oil on the transmission sight glass?.

 

[Godber]

Thanks @NZ Tech. I'll have a better look at the oil colour but you can drive it using the quad lever by pulling back to neutral to change ratios but I'm relying on the quad clutch packs to take up drive which hopefully is ok? Would normally use main clutch for direction changes. Cheers

 

[NZ Tech]

So this valve has an oring on the bottom of it and it flattens off a lot over time.

This will need to be checked. To check it you will need to remove the mfwd driveshaft and remove the little plate on the front cover and then there's a little tab holding the valve in and the orings on the end of the valve. Oring size is 15.300x 2.200mm or part number R28776 or 51M7043.

Unless the front cover is newer then it'll have a 24mm plug and the valve will fall out. This is a long shot and of course I havent checked anything but here how you can for yourself before you spend any cash. Check lube and system and while watching the gauge press down the clutch- if the pressure drops over 5psi this oring above will be leaking and making the clutch at the bottom of its travel not work well. Like i said above tho i've only got experience on 7010s doing this... So might pay to look at the front trans cover and see whats there and attach a picture here.

But it could also be the clutch cable wearing and making it difficult to push the clutch down and linkage issues and the roll pin in the clutch valve breaking/bending and thats a frant cover off job but an inchassis repair. Usually this will just break and you will lose drive altogether.

 

[Godber]

Thankyou @NZ Tech a very helpful post I'll keep you updated. I think as it developed during a spell of hard work and the fact the main clutch just about does its job when cold its probably O rings rather than cable. Thanks