So I inherited an old D7C dozer and it hasnt been operated for about 10 years. about 2 years ago my step brother got it started but he started it in gear and said the transmission was smoking. always a good sign Anyways when i went out recently i found it was in gear. i managed to get it put into neutral and got it started. runs good. pony needs a new starter but i was able to hand crank it. when i tried to use the clutch it would not disengage. took the inspection cover off and found a not so perty sight. i have never had any cat tore apart so not very familiar with it but i feel fairly certain there should be a gear connecting to the lub pump there and im guessing that bolt there was for the clutch adjustment but shouldnt there be like a whole other plate there? And once i get this thing pulled does anyone have a good place to get new parts if im unable to refurbish what i have? 

I have some good used parts for the cluch and more and yes a block plate is missing for the blooking the adjustement and yes the cluch oil pump must have a rear gear

Hi Mark,
as Hector points out you are missing at least one of the lock plates and nuts from the stud we see on the rear face of the clutch, there are two of these that lock the clutch adjusting ring. I has been known for people to forget to lock the second one after adjusting the clutch.

The adjusting ring degrees of turn is very little between the clutch not being able to be engaged, when the main operators lever clicks over centre (too tight) also the clutch can also be locked in the engaged position from being too tightly adjusted and so fully engaged, it can also be not engaging due to being too loosely adjusted-- the main operators lever goes past the over centre point without resistance.

It certainly looks like the clutch could be locked in an over adjusted condition, due to the locks being missing and being driven in gear, and so be locked engaged as you have described as there is normally some threads on the adjusting ring showing--it will likely take some force to turn the ring due to the engine driving it to the locked position--you will need to release all the outer clutch cover bolts holding it to the flywheel to relax the load on the adjuster ring.
By the dings evident on the clutch throw out arm there has been pieces (maybe the missing adjuster locks and nuts) flying around in there which may have got between the pump drive gearing and snapped the pump shaft. It looks like a gear tucked away over in the back corner in your picture that maybe the renegade clutch pump drive gear.
The shaft can also break due to being bent (Fatigue Failure) if the pump is not removed first and fitted last when removing/refitting the clutch assembly.

Hope you can follow this explanation in Aussie English.
Cheers,
Eddie B.

Thought I'd update this now that I got the clutch off. Pic is of all the goodies that fell out when I pulled the housing and clutch off. Found my gear and some springs and a whole pile of metal chunks. Gonna take the clutch to somebody who knows more about it then me to rebuild it and the rest I'll do. Gonna tear open the pump and what not and inspect everything before I try and start trying to find parts. Oh and I have digital versions of parts owners manual and repair manual for sn 17A1 and up d7c dozers.

I should have some spair cluch parts

ok so I have found most of the parts i need to get this guy fixed. however there are a couple that are eluding me. 9f7087 is the 4 studs that go through the pressure plate. 2h1912 and 3h2738 which are part of the lock assembly unless it comes with the lock assembly itself. 9f6658 which is the pin that holds the idler gear for the lube pump in place. If anyone could help with getting these i would appreciate it. also i have downloadable versions of parts, owners, and repair manuals for this machine if anyone needs them