goshdarn water pump

[rocket23]

 My waterpump started leaking. (thru the weep hole). A seal kit costs 55.00 $ and ebay had a whole unit for sale at 70 bucks :dunno. So I'm waiting on the used pump. Pictures had it cleaned up like new, and it had 38 k on the pump. I'll spray some wd on it before I install. ( theory being the seals won't be dry on the oil side before the oil actually hits it).  :2thumbup: But I lost a clymer book, so now I ordered another one. That and the pump I'm waiting for. I'll pull mine off and see if I can throw a kit in it.....then throw that one on ebay.........see if I get any bites.... :deal: Which rvt should I use....black,blue or red??

[roninvt]

 I use ultra black. 

[rocket23]

 Being in burlington, I guess it solves the cold temperature test! Thanks. I was leaning towards the blue. Black works for me :2thumbup:

[rocket23]

 just a quick update, I installed the pump today......Some fersh machinery here! pump came out of a 95 k75. Bolted right up......the gears are smaller and more numerous than the old design. But the sealant is drying and fluids go in tomorrow night. fingers crossed for no leaks!........i did see a small trickle of coolant press out of a bolt hole while I was screwing it in.....if it blows the seal , it blows the seal....time will tell!

[rocket23]

 :mbird Woo Hoo!! :clap: no leaks! , made an awful clatter at start up ( til oil pressure got to it). :yow. Took it for a test ride,up too operating temperature :falldown:. If it didn't leak now, It should be all set later. :yes
 Thanks forum, and peeps for all the advice an write-ups in this endeavor. I lucked out with an Ebay deal, an I wouldn't recommend this way to fix a leaking pump..........mine could go at anytime....but it is a newer one '95, so like I said time will tell. :riding:

[K75RT Keith]

Earlier K's had a different shaft/seal/impeller(can't remember).  When mine went south I rebuilt it with some upgrade kit BMW has.  Can't remember if the dealer told me or I found it in the microfiche.  If you saved your old pump, it might be worth doing the mod and having a spare.

[rocket23]

Yeah, I'll throw the seals and such into it, but now I think they make you use the smaller tooth/teeth version..........But I have no leaks and she runs perfectly........fan comes on, thermostat works.........all is good.....oil is clear..........coolant is still coolant. :riding:

[argent brick]

Recently, I posted a question about water pumps for K bikes over on the MOA website. Someone replied telling me that a pump from a K1200 will interchange, but it is the 19 teeth version like our early K100's and 75's

I wonder if that means you can purchase a rebuild kit for our early style units if you tell the dealer that you have a K1200?

[rocket23]

 I'd have too see that too believe it.......Mine came out of a 95 ,k75 , with the 32 teeth version.......That 19 tooth gear looked like something out of the flintstones when I compared the two,lol.

[JamesInCA]

The K1200 pump is the same as the mid-80s to ~1991 K75 pump, with the 19-tooth gear (excluding the front cover; use your old one).

I have a 2004 K1200 pump on my 1987 K75 right now. The bike has also had a 32-tooth pump on it. They both work; the shafts are in the same locations.

The pumps are interchangeable on the bike, but the gears are not interchangeable in the pump. If you are replacing the gear (shaft) in a 32-tooth, you need to get the 32-tooth replacement. Likewise for 19.

[JamesInCA]

I dislike eBay links because they go stale after a few months. But for illustrative purposes:

1987 K100RS pump - you can buy this now for $85:
http://www.ebay.com/itm/1987-BMW-K100RS-K100-OIL-PUMP-PARTS-ORIGINAL-OEM-/250969766196?pt=Motorcycles_Parts_Accessories&hash=item3a6ef6b934&vxp=mtr

2001 K1200LT pump - buy it now for $25:
http://www.ebay.com/itm/01-bmw-k-1200-lt-k1200lt-k1200-h2o-oil-pump-/221217785661?pt=Motorcycles_Parts_Accessories&hash=item33819b873d&vxp=mtr

Same "Flintstones" gear in 2001.

[rocket23]

 just bought the 25 dollar item....I'm gonna shitcan or sell my original now. I have a decent pump on standby , for half the cost of a seal change! :2thumbup: providing it doesn't leak :yow

[pugsley]

My 1986 K75S water pump seal failed recently, so I was looking for a decent replacement pump body and shaft. The old shaft was very badly corroded in the water seal land area and the shaft was worn in the area of the oil seal lip. The pump body looked like it had had a very hard life sat behind the front wheel for the thirty years the bike has been around. Aftyer reading JamesInCA's comments I just picked up a very good condition secondhand K1200LT pump including impeller and gears for £34. One question though, is the pressure relief valve for the K1200LT set at the same pressure setpoint as the K75S (1986) one that I am replacing it with? It is not a problem to swap them over, just interested to know. When I get it all back together I'll post some photos.

[F14CRAZY]

My 1986 K75S water pump seal failed recently, so I was looking for a decent replacement pump body and shaft. The old shaft was very badly corroded in the water seal land area and the shaft was worn in the area of the oil seal lip. The pump body looked like it had had a very hard life sat behind the front wheel for the thirty years the bike has been around. Aftyer reading JamesInCA's comments I just picked up a very good condition secondhand K1200LT pump including impeller and gears for £34. One question though, is the pressure relief valve for the K1200LT set at the same pressure setpoint as the K75S (1986) one that I am replacing it with? It is not a problem to swap them over, just interested to know. When I get it all back together I'll post some photos.

I have over 10k miles on my K75 since fitting a K1200LT water/oil pump...I never thought about that but at any rate it hasn't burned up yet

[pugsley]

Here are the photos.....better late than never.


Some may find them useful.

[pugsley]

And the state of the old pump shaft.....

[Laitch]

Is the pump reassembled and back on the bike?

[pugsley]

Installed and back on the road. Tell-tale dry as a bone.


I also replaced the oil pressure light switch wiring during the pump replacement as the original wiring was as dead brittle and the insulation was cracked in several places.