MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: roninvt on May 13, 2013, 09:29:50 PM
-
I stopped for coffee this morning and noticed coolant dripping out the weep hole. The dripping stopped after a bit and the hole has been dry for the remainder of the day. This is my first K bike but it seems odd that a coolant leak would seal itself. My dealer is ordering the parts for me. He also recommends replacing the shaft and gear. I have a little over 44k on my bike. Do the pump shafts usually need replacement at this point?
-
On mine the shaft was ok, just needed cleaning, but the seal between oil/water is not too good, so I think that is the failure. If you are having the dealer do it they will replace the shaft to protect thier work. It is not too hard to replace it, but the shaft seal I found rather trick to put on correctly. I had a mechanic do that part and I did the rest.
-
mine has 182,000 on the original and still doesn't leak. It can be a pricey repair, I've seen some leak sporadically then heal themselves. Or they drip a little for years. Longevity may have something to do with regular coolant changes or just luck.
-
Thanks for the info. I will be doing the work myself. I am hoping a new shaft is unnecessary. Normally I wouldn't worry about a little pizzing, but I am planning a trip to Nova Scotia and would hate to have it crap out in the middle of nowhere. :bmwsmile
-
OK, bear with me here. I promise it's worth it at the end.
There were three or four pump variations used on these bikes. Any of them will work, but the internal parts are not all interchangeable.
The very earliest ones ('83-'85?) have a male thread on the end of the shaft, with the impeller held on by a nut. These are to be avoided as the male thread tends to break off when trying to free the rusty nut after 25+ years sitting in water. Your bike doesn't have one of these, but you should know to look for and avoid the male thread.
The next variant, '85ish-'90ish has 19 teeth on the big gear, and the impeller is fastened to the shaft with a bolt that fits into female threading in the end of the shaft. You may have this one, or the subsequent one with a bunch more teeth on the big gear. Either pump as a whole will bolt right on to your bike, but the shaft from one will not fit the other (because of the differing gear ratios and diameters). This one will pump more water at idle than the one with more teeth that was fitted through the '90s. I suspect it may cool better.
Now, here's the good part: The 1999-2009 K1200 pump is the same as the '86ish-'90ish pump with the bigger/fewer teeth on the main gear. Don't believe it? Check the part numbers on the fiche. Same housing, same shaft, same gears, same seals. It's the same pump. And, for reasons known only to the eBay gods, they're dirt cheap. The newest part on my '87 K75 is its 2004 K1200 water pump, for which I paid $35.
(As a side note for those who may be ordering the parts for this job themselves: If you open your pump and find a cast iron impeller, you need to order the new stamped impeller and the matching spacer that sits behind it on the shaft. The cast impeller as-is will not fit with the new seals unless a bit of it is machined off. Just get the new one unless you have a mill in your garage.)
-
Hey JamesInCA, thanks for all the info!
-
I actually had that problem one step farther. ended up my weep hole was clogged and my seal was completely gone. i was having oil working it's way into my coolant (and backing up and vomiting out of my reservoir).
I opened it up to replace the seal and found this shaft looking at me:
(https://lh4.googleusercontent.com/-yu5hv9f63-0/T_mz6azx4dI/AAAAAAAAijo/6VSo_HkKFXU/s400/IMG_20120623_142927.jpg)
so yeah. new seal didn't fix it and i had to order a new shaft (and seal). my bike is an '86 and was at about 135k.
-
... The 1999-2009 K1200 pump is the same as the '86ish-'90ish pump with the bigger/fewer teeth on the main gear...
Which old and new pumps are the same?
86-95 K75 Pump Fiche (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51743&catID=11&catname=Engine&bindName=WATERPUMP_OILPUMP_-_OIL_FILTER&bindCat=11_1818)
99-04 K1200 Pump Fiche (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51717&catID=11&catname=Engine&bindName=WATERPUMP_OILPUMP_-_OIL_FILTER&bindCat=11_2306)
Some of the part numbers are the same (like the housing) but others are different (drive shaft, shaft).
-
I actually had that problem one step farther. ended up my weep hole was clogged and my seal was completely gone. i was having oil working it's way into my coolant (and backing up and vomiting out of my reservoir).
I opened it up to replace the seal and found this shaft looking at me:
(https://lh4.googleusercontent.com/-yu5hv9f63-0/T_mz6azx4dI/AAAAAAAAijo/6VSo_HkKFXU/s400/IMG_20120623_142927.jpg)
so yeah. new seal didn't fix it and i had to order a new shaft (and seal). my bike is an '86 and was at about 135k.
That's the older, and I think preferable, 19-tooth gear.
-
... The 1999-2009 K1200 pump is the same as the '86ish-'90ish pump with the bigger/fewer teeth on the main gear...
Which old and new pumps are the same?
86-95 K75 Pump Fiche (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51743&catID=11&catname=Engine&bindName=WATERPUMP_OILPUMP_-_OIL_FILTER&bindCat=11_1818)
99-04 K1200 Pump Fiche (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51717&catID=11&catname=Engine&bindName=WATERPUMP_OILPUMP_-_OIL_FILTER&bindCat=11_2306)
Some of the part numbers are the same (like the housing) but others are different (drive shaft, shaft).
Your first link is showing parts for the 90-95 K75RT, which does not have the earlier pump that is the same as the K1200 pump. So the pumps on those two pages are different, and the gears/shafts are not interchangeable. (The seals are all the same.) If you're going to buy a new shaft, you must know which one you need to buy.
Use this link for the 86-90 K75C, which shows both pumps: http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51741&catID=11&catname=Engine (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51741&catID=11&catname=Engine)
Note that either pump will bolt to any K75, K100, K1200 (and I presume K1100). It's the gears that are different. The mating to the bike is the same.
The critical parts in all the diagrams are #9 (drive gear) and #11 (main shaft, which includes the large gear). Note that #11 has a notation of either "z=19" or "z=32." That's the number of teeth. Each pump also needs a drive gear with teeth that fit, so the drive gear part numbers are different as well. Unless something strange has happened, you won't be needing to replace the drive gear.
I also see that here, at least, they're showing the same housing for all variations. This is actually incorrect. The 32-tooth gear will not fit a housing for the 19-tooth gear. Really - the gear has a larger diameter, and the clearance to the housing wall is minimal. (That's how the oil pump works - it draws the oil from the intake into the space between the teeth, and slides it around to the output, right up against the housing wall.)
Note that you can buy a complete used K1200 pump for a fraction of the price of either shaft (19 or 32) from the factory.
-
BMW of Chattanooga's fiche has a convenient feature most of the others lack: For each part, they show all the models the part fits. Here's the page for the 19-tooth shaft:
http://www.bmwmcchattanooga.com/products/BMW-Motorcycles/2004/K1200/Shaft-Z=19/1031205/11411461793.html (http://www.bmwmcchattanooga.com/products/BMW-Motorcycles/2004/K1200/Shaft-Z=19/1031205/11411461793.html)
Note they specify it for all K75, K100, and K1200 (brick) bikes. No mention of K1100, so I retract my presumption above. Don't know, don't have a K1100 to check with.
Also note that the fact it'll fit any K75/K100 doesn't mean it will necessarily fit with whatever pump is currently on that bike, as there are the two variations. It will fit, if the component it is replacing is the same.
-
surprise,surprise the water pump I got on ebay has the 32 teeth gear...which will mate right up too my motor........just waiting on cooler temperatures!...near 90 right now,screw that noise.....work smarter not harder. :2thumbup:
-
I have a one drop leak from the weep hole after a ride. When would it be necessary
to do the rebuild on the water pump. I don't plan on going anywhere far on this bike.
Does anybody think changing the coolant would help? Can I use Honda car antifreeze to add or renew
the existing BMW antifreeze.
Bill
-
Antifreeze doesn't know brands.
As long as what you get/buy is listed/safe for use with aluminum engines(and most are nowadays) you should be fine.
What ever you do DO NOT buy/use any of the DexCool crap.....
Make sure that your weep hole isn't plugged up/restricted, it's easy to overlook and it can fill with road grime.
It's not that much to drain/flush the cooling system. It actually may help with your issue. YMMV