Join Date: Oct 2010
Location: Yorktown, VA, USA
K75S Water Pump Seal
I've also posted this to the IBMWR BMW-Tech list… looking for any assistance
A rather frustrating day today.
I had noticed that my coolant recovery reservoir had dropped a bit a couple of week ago so I checked the weep hole to find it wet with coolant.
So, I researched the replacement procedure, found it on IBMWR to include the addendum to address the new water pump seal. The impeller, oil, water pump seals and two O-rings were ordered and received along with new long-life coolant and everything for an oil change. The oil pump shaft is in good shape, no pitting.
The replacement process went well with the water pump gasket looking trashed even before driving it out of the housing. All the parts went together as described in the process and I was sure to use the impeller bolt with a washer to pull the shaft through so as not to destroy the water pump seal. But… there was a bushing that came out with the seal that is not identified in the BMW 1988 service manual, Haynes, RealOEM parts breakdown nor mentioned in the IBMWR procedure. So I figured, possibly incorrectly that it was part of the original water seal.
As you probably have guess, after fluid replacement and tank installation all appeared fine for a bit. Then there was a coolant drip out the weep hole with possibly some oil.
Disassembly next and I know the seals will have to be replaced but is there a place for the bushing mentioned above that caused it not to seal? It's 3mm thick, inside diameter is the same as the oil pump shaft, outside diameter is the same as the oil pump seal (water pump side). It is cut approximately 1mm thinner along the inside.
My thought now is that this bushing goes in after the oil seal with the cut side toward the oil pump seal.
All assistance is greatly appreciated. Although I have other motorcycles, the weather is great and I should be riding, not wrenching.
1982 Yamaha XJ650RJ Seca
Last edited by stokester; Apr 4th, 2014 at 7:58 pm.