Greasing the Throw Out Bearing
on a Unimog 404.1, in the truck.

Remove the doghouse and all covers from floor of cab with approximately 3000 bolts. It is not necessary to remove the large boot from over the levers.

Remove the bell housing access cover (2 bolts).

Pull cotter pin from rear clutch linkage clevis and drop the link to allow the yoke to move rearward.

Pull the yoke and TOB rearward for better access (this is down inside the bell housing).

Carefully remove the wire TOB retaining clips from the pivots on the TOB assembly. "roll" them off, rear to front. Note that this is not a required step. The TOB could be greased in it's mounted position but that process has to be done mostly by feel. Also, remember it's not really easy to get the retaining clips back on afterward. I think next time I will tie a string to each clip to be sure I do not lose either down inside the bell housing. Duane Russell suggests stuffing a few shop rags under the TOB to prevent the clips from falling into the abyss.

With retaining clips removed, the TOB can be rotated to pass rearward through the yoke, and end up behind the yoke where it's "easy" to get to. It is, of course, still around the transmission input shaft so you still have to work down inside the bell housing access hole.

With two screwdrivers on opposite sides of the TOB, gently pop the face off the bearing. The face is the part which normally contacts the ring on the pressure plate fingers.

With the front of the bearing removed, a finger can be used to force grease into the rear portion of the TOB where the roller balls are. Rotate the TOB assembly around the transmission shaft. A pointy grease injector like used for a CV 'U' joint might be handy to use but I just loaded one finger with grease, wiped into the TOB, and repeated the process all around the circumference.

I did not take the retaining ring off the bearings, nor did I remove the old grease. Purists would cringe, but I did not want to take the chance of dropping any bearing balls.

Once the TOB is greased, push the front half back into place, if it will go. If not, then insert it as far as it will go into the TOB assembly. The grease will probably hold it in that semi-installed position quite well. It will be forced back together later.

Realign the tangs of the TOB onto the guides on the ends of the yoke, and reinstall retaining clips. Note that some clips are installed 'over the top" around the yoke ends, and some are around the bottom. Duane's and mine were both around the bottom. I later changed mine to fit across the top.

Make sure the front of the TOB is still in the correct groove in the TOB assembly. Reinstall the pin into the clevis of the clutch linkage. With the TOB still in 2 pieces this may be a tight fit (there might be less than zero free play).

Once the clutch linkage is back together, press the clutch petal. The TOB should pop back together. If not, crank the engine a few revolutions while gently pressing the clutch petal to reassemble the TOB.

Check that pedal freeplay is still right.

Bob Ragain

Eric Messersmith's addenda..

Follow the RMM instrcutions and remove the sheet metal, disconnect the clutch rod, open the bell housing hatch, pop the TOB open etc. Be sure and lay rags in the bottom of the bell housing and make a punch mark on the clutch shaft and yoke in order to easily re-insert the shaft exactly where it was.

When you are in the bell housing,
1) remove the TOB clips;
2) remove the pinch-screw that holds the TOB yoke on the clutch shaft
3) push the shaft out. Voila! With the shaft out of the way, you can easily reach in and use both hands to place the clips back on the TOB and fork. Then, with the TOB clipped on, just push the clutch shaft back through the yoke. Easy stuff.

Happy Mogging,

Eric
'60 404 Pritsche
S.F., CA