Where did the oil come from, looks like all the parts are coated, friction material looks dry though.


Talk about a mess, I have a D7 that apparently never saw any grease in the pilot bearing long before I got it, 15 hours later on the meter, the drive links that connect the main flywheel and clutch assembly could not take the strain anymore, the thick driven plate in between the 2 clutch plates was wobbling around when the clutch was not engaged and I assume when the clutch was engaged it grabbed the plate wherever it landed, lot of vibration, fenders were flapping, I knew something was up, and then the smoke started coming out of that compartment, the links let loose and the material left in there was like a big mouse nest, the links rubbed off on the upper bellhousing, so I shut it down, eventually removed the clutch assembly, and found that the pilot bearing was disintegrated, the bore eggshaped. Mind you, I realize the later oil clutch is far more durable, but the fact that this thing held on for as long as it did is amazing, if you keep an eye on things, and knew it needed some work, you certainly had enough time to get the tractor out of the field etc.
This clutch original, the tractor was owned by the corps of engineers until 1970, so I can see what happened, they kept the O.D. green paint up to date on it, probably ran it every so often, but was never used, until bought by a farmer, I think I'm the 3rd owner. There is a metal data plate rivetted to the inspection cover, that says, grease daily, (pilot bearing) ironically, that never occurred, LOL !


I was a bit intimidated or a little confused about what to do with this assembly, luckily I found a good used complete clutch assembly from a dismantler, from a running tractor. The friction linings were useable, but I decided I won't reinstall the clutch until the linings are replaced, both clutch brake and clutch plates. I was aware that the friction material, (segments) are available, but wondered if the holes were drilled in them, that would be a pain in the arse to drill them from a template of the old segments, then counterbore the holes for the rivets, then do all the rivets and attach the segments, you can get the hand tools from Cat, it's in the tools and supplies catalog, the old catalog from the 50's even shows the rivet press.

It did not make much sense to do this work, when you should probably be able to utilize an outfit that manufactures/installs friction materials, I had found a couple of places that does this work, over 100-150 miles away, nothing local yet although I've yet to call some of the crane outfits to see if they have anyone local that does friction work, should be a done deal then.

The only issue I had was about the thickness of the friction segments, wondered if anyone knew how thick they are, and what type of friction material is best, the outfits that do this work would probably be able to recommend the correct material, but how do they know how thick the material is supposed to be on one of these when it was new?

In the interim I've been turning the motors over by hand monthly to make sure they don't seize up, been sidetracked on other projects sitting in the yard, but I think I'll get to finally get the clutch done before winter.

The sourse of some of the oil if not most was the pony motor main seal leaking and runing down behind flywheel and into bellhousing.

I forgot, that one has the horizontally opposed pistons and is mounted on the back of the diesel, should have thought of that, I saw the belt in one of the photos, oil sure can travel and get everywhere, well at least it's not all rusted up !

Billy,
The clutch rebuilders I know have specs on all the linings. Usually from the part number or sometimes the application. The problem may come in when there's a serial number break, and a different style of part used. Then it may take eyeballing the part to get it right.

The few linings I have bought were already drilled and countersunk except for one brake shoe that we knew we couldn't get from the part number, so they supplied a section of brake lining and some rivets and I did all the drilling and countersinking. Wasn't much trouble, just cut the lining to size, clamp it in place, drill from back side to mark hole and then redrill with countersink from lining side, stick in a rivet to make sure everything stays in alignment and move on to the next one. But that wasn't a clutch!

Ok found clutch segments through Martin Tractor (Cat Dealer here in Topeka) part# changed to 6Y7169 need 12 @$11.26 each did not sound out of range so have them and rivets ordered also clutch brake was $59.42 so I have it and rivets ordered Parts should be in next week so have plenty of time to clean up where it was welded and drill out old rivets. I think my brother has an old rivet press but might take awhile for us to find it.
I need to get with Hector Gemme up in Cannada he has the main plate and the link shackles I need.
Russell

I had wondered if that was the case, years ago it was probably a common part in for re-lining, I always try to help with part numbers, old parts or any pertinent info, in hand, and I'd think the application being a clutch, these shops/manufacturers of friction materials would probably know, I figured it would be best to bring in the parts to be re-lined, one thing I noticed is that the first plate comes off relatively easy, then the driven plate, but that other plate is locked in with that hardenend bushing/bearing which the pilot bearing of the driven plate rides in, was wondering what is used to get that off, must be some sort of puller or something. The clutch brake, the steering brakes and the brake on the LeTourneau PCU on mine don't look too hard to do by hand if need be, but some of the shops that do re-lining I've found on the internet, appear to make short work of these jobs, plenty of friction material on these old critters to replace, the only one on mine that concerns me is the PCU, dog bowl shaped driving and driven cones, although the LeTourneau manual does describe the procedure, the odd shape, round eccentric or concentric, depends on how you look at it, if someone could re-line those, that would be the icing on the cake !

With those older Cat engines the rear main bearing gets worn back esp. at the screw area of the crank that is supposed to screw the oil back in the pan & when they do the oil gets by that area & back into the bell housing area which houses the clutch in there.

Got lucky my brother was able to find his rivet press and looks like the punch that is in it is the right size. Got all the old rivets drilled and punched out and the clutch brake cleaned up on the lathe, the weld was a little hard on carbide cutter, now just have to wait on parts.
Got the main clutch plate and 2 sets of link shakles ordered.
Still need to pull rear seal on pony motor.
Does any one know, is the rear main engine (not pony motor) seal replaced by pulling the oil pan and rear main cap or can it be replaced buy just pulling the flywheel?
Russell

Yes the pan would need to be dropped to get at the bearing cap. Also on each side of the cap there is packing cord that has to be driven in after the cap is put back on & torqued down.Cat has that & comes in a roll.I never used this type but I,d think the treated cord that plumbers use would work fine for it.I,ve packed probably 100s of them at the dealer & you have to lap it back and forth as you drive it in the groove machined out along each side of the cap.It has to be drove in tight in the groove too.

your d6 do not use rear crankshaft main seal