WD clutch grabbing when it shouldn't

Thanks Steve - got the cover off transmission/hand clutch.  I think I see the big snap ring and looks intact.  Shop manual says with clutch disengaged and plates forward look for .030 between driven discs & pressure plate.  I'm getting closer to as much as .038 with the stack 'relaxed' (hand lever forward).  Measurement seems wider further away from where existing shim is or down the plates.  Bump the starter to access the other shims?  I'm assuming there are three locations.

I will throw in a picture that may or may not help? Mine is a three clutch plate WD45. Yours is a 2 plate WD I believe. It looks like your adjustment shims may be all gone? Which may mean the clutch plates are worn??

 You should be able to turn this unit. That's how the shim adjustment is made in the tractor.

If the hand clutch is not locking back, it could be an adjustment or additional worn parts in the linkage and or 2 piece brass collar. 

Dont let me get you off track here. Dr Allis or Mack may be along to  assist you!:)

Been a couple days since I was in there. 

Regards,

 Chris

Here is a link to a thread where I went through the hand clutch on my 45. Lots of pictures. It may give you some ideas.

 Your welcome, and these tractors are 70 years old and some have been worked hard. as a ref I think the shim stack is maybe .25 inch thick when new. (Maybe less???) and the clutch plate are IIRC .10 inch thick. With out taking this out there is not much other than the shim work and the brass throw out unit to be replaced.

Regards,

Chris

I looked up another old thread of mine, unfortunately the pics were all on p-bucket and are now dead. Went through the torque-tube/hand-clutch on that one too.

I have quite a few parts for these hand-clutchs, and I'll bet LON has a lot more.

Chris - yes in some photos I'm like 'wow that's a lotta shim stack!'  My measurement of drive discs is probably off.  The shifter collar looks like it could be removed as it's two halves?  There is play in all that stuff but of course I've no idea whats acceptable. 

Here is a too long update but hey, pictures!

Had the hand clutch open again (and again) and tried a few different things to alleviate the very slight 'grabbing' of the clutch (enough to just rock the rear wheels forward then they settle back) when engine clutch in gear and hand/transmission clutch disengaged.  Also hand clutch not staying locked back - would pop out under way.
Removing all shims had made the grabbing worse.  Because I had found the shims distributed unevenly, tried putting them back similarly thinking maybe the uneven arrangement was trying to level out a high spot.  One shim on each of two retainers and 4 or 5 on suspect retainer for whatever reason showing a larger gap between plates.  Also a curious little divot on the back plate at this retainer location, maybe marked by someone?  Removed springs - couple springs have wear spots where they are a little flat, and they aren't straight but otherwise push the plates apart.
Tested.  Still grabbing, maybe a little better than 'no shims'.  Clutch still locking back well.

 
Into the trans clutch again.  Drained gear oil.  3 drain plugs 2 fill plugs.  Tried to clean everything.  Tried to take some measurements.  Plates have a raised edge making them harder to measure, drive discs measured something like .154" and .158".  Bearings and gears leading down to PTO all looked good. Grooves no smooth spots on discs and plates.  Cleaned shims and put them back evenly - 2 at each retainer.  Tested. 

 
Worst damage I could find

Drive discs groovy not as thick as plates but thicker than others I've seen in photos

In first gear with hand clutch disengaged let out the engine clutch.  No grabbing at all.  Puttered around the yard and while much better, still wanting to grab a little bit when stopped but still in gear.  Feedback thru the hand lever was much smoother whereas before you could feel more vibration thru the lever when engaging. Maybe it just needs some good hard use to wear even

As I understand it shims are typically removed as the plates wear down, evidenced by the hand lever not locking back or staying locked.  I did rotate the washer retainer to a new location first time in the clutch and the lever has stayed locked back since then...so I'd like to add more shims (but I'm fresh out) to see if the 'grab' goes away and if the lever will start to pop out of lock again.  Theorizing here that maybe the lock back failing was due to wear/damage on washer retainer, and not necessarily discs being worn out.  Of course this is the first clutch I've played with so that theory is not based on very much.  

Seems like the separation of the discs is dependent on how freely they travel - the springs of course but also maybe fit at retainers and dirt generally, like on the splines of the shaft down below.  Sliding the discs by hand feels like they could get hung up or be impeded. 

Plate tabs must have to slide freely here within retainer.  Spring holes look okay.
 

Seems like about 22qts came out and only put back 18-ish as expected with PTO.  Used both fill plugs. 

 

Didn't think the rear diff was gonna yield anything until poked at the little fudge disc at the right blocking the drain.  Not sure but I think 'TB' stands for Tractor Boss