Case dc-4 diff oil seals

[tak8098]

Any tips or tricks on how to replace the oil seals on the differential on a DC case serial #5507917. I was going to go through the brakes ,but when I pulled the cover off I got a bath in gear oil. Thanks for any and all replies.

 

[rustred]

which cover?... the brake cover? which seals? if your pulling brake cover off and getting a bath , that's a big leak.

 

[tak8098]

yes it is the brake cover and the seal is for the brake shaft

 

[chuck machinist]

Drain the transmission the rest of the way using the rear drain plug, about ten gallons. Remove the bearing carrier cover. It has the seals , or what is left of them. try not to destroy the shims behind the bearing carrier. They keep the back lash correct with the rack and pinion. You may want to support the bearing carrier shaft when you reinstall the bearing cover. John Saeli will provide you the seals you require.CM

 

[tak8098]

Thanks

 

[Ron Sa]

I replaced the right side leaking seal on one of my 52 DCs which is the same as your tractor with that serial number. See picture at bottom.



Without going into detail, the cause of the leaking/damaged seal (besides age and hours of use) might be END PLAY in the shaft assembly. End play in a shaft supported by taper roller bearings allows the shaft to ?drop down? (because of the taper) and the seal to have to tolerate a small amount of shaft gyration at the seal-to-shaft interface. Not a desired situation.



Like me, you may want to readjust the end play in the shaft using the shim pack. The good news is the big gear on the shaft is a spur gear and not a spiral bevel gear. Therefore, there is not a backlash adjustment at the gear teeth that has to be dealt with. The bad news is there are two steel-on-steel interfaces (like thrust bearings but no thrust load is allowed) at the differential that must endure relative motion for the differential to function.

Therefore the tedious situation that must be dealt with is to minimize the end play in the shaft assembly without preloading the two steel-on-steel interfaces. I shot for a .005 end play in the shaft assembly.



I believe in the saying ?the pain of doing it right does not linger near as long as the pain from having done the wrong?. Therefore, here are the ?tricks? I used. (to use your word)



The first trick is I jacked up the rear wheel on the side I was working on. This allowed me to turn the tire and the brake shaft assembly ( tranny in neutral) in order to know when it was experiencing a slight amount of unwanted preload.



The second trick was to first leave the shim pack out and to reassemble the bearing/seal support using the three bolts with cleaned threads for easy turning of the bolts. I also left the new seal out at this point and removed the o-ring ---both removed to prevent drag and a false sense of preload.



Lightly tighten the three bolts evenly until there is preload on the shaft assembly. A preload can be detected by turning the shaft assembly by turning the jacked up tire----also by sensing a small torque on the three bolts.

Hopefully, there remains a gap where the shim pack goes. The next trick is by using a feeler gage and by turning the three bolts in or out, make sure the gap amount is uniform all the way around. Do this procedure until the preload is light and the gap is uniform.



I used a feeler gage to measure the uniform gap. I used a mike to measure the shim pack thickness. I adjusted the shim pack thickness to being .005 more than the gap measurement. I installed the shim pack and tightened the three bolts. I opted to leave the seal out and to retest for any drag/preload in the shaft assembly. I would have added another small amount to the thickness of the shim pack if any preload/drag at the shaft assembly was sensed.

Once I was happy with the situation, it was time to apply the ?pain of doing the right?--- of once more taking the pieces apart and install the seal, the o-ring, and finally the entire brake assembly.

 

[Ron Sa]

PS to my recent reply. Your 51 DC brakes and shaft assembly are similar to my 52 DC but a little different. The seal and the outer brake assembly are different but the procedure I outlined is the same. Good luck getting your leak fixed.

 

[tak8098]

Thank you for your reply.

 

[olgentdc]

try LUCAS HUB SEALER , NAPA should have it