Changing large shaft on oil/waterpump.

[Enfield]

Hi - first time poster here - great place  :2thumbup: . Got one short question - I am about to replace the shaft on my oil pump - mounted on a 1984 K100. I feel pretty sure it is the one with a nut…..as the impeller was welded to shaft :dunno . I have a complete service kit with new impeller, bush etc. and just want to be sure if I can just fit a new shaft ( large gear) with correct nr of teeth and made for a bolt instead?
Regards
Chr

[Enfield]

Arhh damn….first time poster…….in the wrong section…sorry :musicboohoo:

[BrickMW]

Hello, and Welcome!

There was a design change. Not exactly sure what you are trying to accomplish, but a new shaft in an old seal may not work.


Maybe add some pics of what you have and what you're trying to do.?.


Meanwhile, have you read this?

[Enfield]

Sorry will try to describe better. I am going to change all seals etc. in oil / water pump. As I took it apart I could see that the impeller is welded on the shaft….I suppose then that it s the one to be avoided ( one with nut that tends to come loose). As it has been ruined by welding and wear I want to change the shaft along with seals etc. I was just wondering if there has been any other changes to the shaft apart from going from male to female thread? Or if I have to go for a new and very very $$$ pump.
Best regards
Chr

[BrickMW]

Does your impeller look like this?


*NOTE* (From MaxBMW parts fiche)
When replacing the seal and spacer behind this, you must also replace this impeller if you do not already have the one in the photo. The old style (cast) impeller will not work with this assembly.

[Enfield]

Hi. I have the new style impeller as part of the kit and will mount it. But it is the old style that some "…." has welded to the shaft

[BrickMW]

Ahhh... So you will then have to cut/grind old impeller off and replace the shaft with p/n 11 41 1 461 793 SHAFT - Z=19 (to 01/90) Has 19 teeth.


p/n 11 41 1 461 183 SHAFT - Z=32 Also uses the new style bolt, but is for units post 01/1990 and has 32 teeth.


Both shafts use the same seal, spacer, impeller, and bolt.


Have you acquired the special tool for installing the seal?

[Enfield]

Thanks - so no problem replacing the shaft ! And no - haven't got the special tool. Maybe I surrender and have a mechanic to fit the seal :-)


Chr

[Enfield]

 No matter if it was nut or not[emoji23]


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[John Lang]

Haynes does not mention a special tool requirement for re-fitting seals to the shaft. They suggest using a 22 mm socket against the hard edge of the seal and 1/2 in. 'drive' (hardwood dowel?) to coax the seal into its seat. Would this suffice?


As I have a skim of oil in my coolant overflow tank, I need to change the seals and was working up courage to DIY it. I have no special tools.


The Ottawa Motorrad shop does not accept bikes older than model year 2000, which I find strange/unethical. I am guessing that their mechanics are all younger than my (1987) K75.

[John Lang]

I just realized that "1/2 in. drive" refers to the 22 mm socket, one with a hole large enough to fit around the pump shaft. There are good posts here on this subject.

[Enfield]

I mounted the seal first, then I inserted the gearshaft through the Oil seal and then used the Impeller bolt and a washer large enough to rest on the edge of of the waterseal to drive it through the seal.


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[John Lang]

Thanks Enfield. That was probably the 'special tool' mentioned. I'll do the same.