just bought mid 50's d47u within one hour the clutch was slipping, what is proper way to adjust this clutch. Any help ?

Instructions attached:

Just a little add-on about d4-7u clutches. I'm almost about to scrap mine after finding I can't get my main lever to move. I left it in the disengaged [forward] position when I parked it but the clutch still apprently rusted to the flywheel. Starts up and smokes in neutral down in the clutch well.

After soaking the clutch and flywheel with everything from Kroil to other penetrating oils and trying to force the collar [around the shaft into the transmission] to move forward or back, I resorted to putting it in gear and towing it to try to break it free. Nothing works. Decided to break down and call the Cat service people out [checked my bank account first]. They didn't want to have anything to do with it . Said I was doing all the 'right things'.

Anyway, the point is you might want to get some advice from the old hands as to how to store the machine over winter -clutch engaged or not or part way or what. Once they get stuck by a little rust. it's no picnic trying to get it undone. I am putting off selling it or scrapping it because I just like the tough old thing, but that clutch.....

Hi, Hartlyboy.
That sounds a little odd to me, that the clutch would rust to the flywheel. If my memory serves me right - and assuming that your clutch plate still has some facing left on it - it should be clutch facing material in contact with the flywheel, not metal to metal, although it just might be easier to break a steel-to-steel rust-up. For there to be smoke coming out of that compartment, there would need to be movement of something against something to generate that sort of heat.

Are you sure that it is not the thrust collar rusted to the shaft? Does the thrust collar move at all on the shaft when you move the lever? Can you wriggle the individual links from collar to fingers?. With the clutch in the dis-engaged position, you ought to be able to undo the adjusting collar clamp bolt and turn the adjusting collar to either tighten or loosen it. Is this the case?

I gotta tellya, I have to be AWFULLY frustrated to consider scrapping a 7U D4 just 'cos the clutch was stuck.

Where there's a will, there's a lawsuit.

Ooops! Sorry, wrong quotation. Where there's a will, there's a way.

Thanks for your thoughts on the clutch problem. The way you have thought it through makes more sense than what I've been told -and blindly accepted. The collar does move, but only a little. The linkage seems to want to move it forward when I tug on the lever but I haven't been able to coax it any further. Haven't tried lossening the bolt and turning it. Didn't think that would have any effect since the shaft has to rotate when it's in gear and being towed. Not sure how the collar could then be rusted to the shaft. I kept hoping the dang thing would break free and I wouldn't have to try to figure out how to readjust the clutch if I started loosening bolts down in there.

You're right about scraping the old beast. After the effort it took to get the pony motor to start and run right, the Hahn seat, the sweet bellow and good oil pressure and the Alemite grease gun I got for it and , and......

Hartleyboy. .DON'T SCRAP IT JUST BECAUSE THE CLUTCH IS STUCK!! If the critter weren't so far away, I might have suggested you sell it to me for scrap price, but. .

Can you get any movement at the lever? If so, where does it stop? There's a slight possibility that the top shaft might have rusted and frozen in the case, if it's not that and it's not in the linkage or the thrust collar then the clutch plate probably is held to the flywheel and rear plate with rust. I've seen one (a D4 7J) that was frozen up solid and that was 'cuz it had sat without the inspection cover for several years and had filled up with water. Once I got the engine and transmission apart, a hearty application with a 4# rubber mallet got the clutch apart. Flywheel and rear plate had to be faced and rust chipped off the clutch disc but they were reusable.

If you're lucky enough to have a two piece transmission cover, you could pull that and have pretty good access to the clutch itself. If you don't, it's probably time to consider either pulling the engine or the transmission lid.

The confusing thing to me and the reason for mentioning to the original poster the need to take some precautions is because my inspection plate cover was on and sealed pretty well. There isn't any rust in great quantity in the well and the linkage is free. The lever just just won't move the collar forward yet somehow it's engaged enough to rub the flywheel and actually turn the engine over when it's pulled in gear. Breaking that thing apart to get a clutch free just isn't in the cards so I'll keep doing what I can through the inspection plate opening. When the crops are off I might try towing around the field with another dozer in the hope that something will loosen up. I think I will try to loosen up whatever I can as far the bolts down in there since at this stage I don't have all that much to lose. Thanks for your thoughts and suggestions.

hello Hartlyboy, make sure the leavers are not frozen up ,towing the tractor around want free up the clutch brake ,spray some lube into the clutch brake collar ,but try not to get t on the main clutch ,the clutch brake maybe frozen just on the main clutch face fingers .towing it will only wear your clutch out,bruce oz

Hi Team,
OM's data seems to have gone astray, so here are scans from my OMI.
Hope this helps.
Cheers,
Eddie B.

edb, my d4-7u has a serial number of 7u2450 but the inspection plate is on top on the floorboard. I assume taking the collar bolt loose lets you rotate the entire collar in either direction? Would doing that have any effect on the clutch brake? If that is what is rusted up as Bruce Oz has mentioned I need to figure out how to get motion to that mechanism to try to free it. With the limited space to work down there I'm willing to back off the clutch as far as I can if that also backs off the brake. Does it usually require a pry bar to move the collar around?

Bruce, edb, thanks for adding your thoughts on all this. By the time we are done here , some of us are going to know a bit more about these clutches, fer shure.