The Unimog Wherehaus

E-mail Dirk Rautenberg


Water PumpTeardown
Water Pump Bearings

Ahhhhhhhhh, the waterpump !! A vital part of your motors perfomance. Keeps the block, head and oil cool, even has the wonderful alliance with antifreeze to keep your body warm through the heater core. As it is a wonderful design generally, it lacks of quality.

What started this whole thing recently was a customer complaining about the play in his pulley and he was about to go on a trip with his dad to Yellowstone National Park. As a back up, I sent him another used pump. Well, I have 16 trucks here and most of them had a bit of play in the pulley, some worse than others. So, I took a few pumps off and headed to the local machine shop to have them pressed apart.

The process was simple and the findings surprising. Open bearings are used without the possibility to re-grease them; prone to premature failure. At the local bearing/ seal house, replacement bearings in sealed option came off the shelf and after cleaning up the impeller shaft the fix was simply a procedure.

Here are some step-by-step photo supported instructions on how to save your water pump from its predestined fate.
(A new replacement pump will have the same crappy bearings inside as the old one. Trust me !!)

You can find the way to actually remove the pump off the engine in the repair manual. As said, I had several pumps off to show you the procedure, so it is not always the same pump body shown in the pictures.


Take the rear bolts out of the housing and seperate the two cast pieces.




The impeller is now exposed. Here the machine shop/ press comes into play. The pulley flange needs to be pressed of and the bolts of the seal flange need to be removed.


Then reverse the pump to press the shaft out of the impeller.






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