Oil/Water Pump Rebuild - 1996 K1100LT

Short Story - blew a hose, replaced hoses, found gunk in coolant, deduced it was oil. Replaced the pump seals and botched it - had coolant leaking out the small weep hole at the base of the pump housing. Re-ordered parts and now going to give it a second try.

I think I might have put the oil seal in backwards. It looks like this (rubber ring)......



I think it goes into the impeller side of the pump with the open end showing the small spring (seen on photo) away from the impleller?

When I finished the assembly, the impeller and geared shaft were very hard to turn by hand. Is that right?

Also, any idea on what the copper ring - also in photo - is for? I don't recall taking one out of the original assembly.

It looked to me like the rebuild was not too difficult, but I think I might be losing my mind. Any advice would help.

I found by experience that this is one seal that I personally will always take to the dealer for the install. I messed up my first try and since I had the unit off the bike, decided to just take it in. That was very inexpensive for just the seal install, then I remounted the unit on the bike. That was the '85, did the same on my '93. So far, the '00 has not needed this work. Doesn't answer your question, but that was the best solution I had and over the years, many here have concurred.

Thanks - I appreciate the advice. I was kinda leaning that way. Just did not want to admit defeat so easily.

David,

Having never had to rebuild a Brick water pump, I can not address that specific seal, BUT usually the side of a seal with the spring on it goes TOWARDS the fluid that you are trying to keep in.

Also, usually, the hollow side of a seal (the side that is showing in the photo) goes toward the fluid so that the fluid pressure can push the backside of the rubber tighter against the shaft.

From your description and what the photo looks like, it appears that you may have put the seal in backwards which would definitely leak like crazy.

I don't have first hand experience with the WP seal R&R (yet) but here's something that may be of help.


http://ibmwr.org/ktech/water-oil-pump-rebuild.shtml

and the update for the new seal design.

http://ibmwr.org/ktech/water-oil-pump-rebuild2.shtml

Good luck

Thanks for all the replies. Apprieciate the advice.

I took the unit to the local shop that works on BMWs. Looks like the main shaft is worn and needs to be replaced ($190). They'll install the seals and the new shaft (1/2 hour labor) and then I'll put it back on the bike.

I'll update when I get it back and running.

Glad you are getting it done....the price increase seems extreme in shear numbers, but it is really only a bit over 5% per year for 19 years.....so I guess that is not too bad.

Copper crush washer is probably for the coolant drain plug on the bottom of the water pump.

Update - got the seal redone by the shop. Put the pump back on the bike. Still leaking coolant from the weep hole at the base of the pump. Probably going to have to take it in to the shop.

Talked to the mechanic and he said to take it for a test ride. The graphite seal sometimes needs to heat up and set in to seal. Fingers are crossed - I'll update with results.

40 miles later and dry as a bone! I'm back on the road.

Sadly, it's possible that I installed the first seal correctly. I had the identical leak problem from it. Wish I had dug into the forum more and found the posts that discussed breaking in the seal.

But at least I'm up and running again.