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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: FranK75 on November 14, 2015, 09:51:07 PM
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Parked my '91 K75 with 36K miles a few days ago and saw that oil was leaking from the water pump. Searched the net for info and saw how to remove the pump, take it apart and get new seals to rebuild it. Since it was leaking oil and not water I am thinking the water pump seals are good but the gasket seal between the pump body and the engine failed allowing oil to leak. I am going to reseal the pump body and reinstall. I'll let you know if this fix works. Also - antifreeze is not easy to dispose of. I have to take it to a radiator shop.
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The pump is actually a water and oil pump. It is a two section pump.
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I get that. Seems like the oil was seeping out of where the pump body meets the engine. I am hoping that resealing those parts will fix the oil leak
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There are no gaskets between those parts. The pump / engine block mating is metal to metal. You'll have to use an anaerobic sealant like Permatex or Loctite after cleaning the surfaces meticulously of any previous sealant.
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+1 on rbm statement. Clean the surfaces very good, I mean clean and then apply a light coat of sealant, light, allow it to become tacky and then tighten bolts in an even manner. I put a new Impeller shaft in mine once along with new seals and then put it back together then it leaked again! Back apart, antifreeze everywhere, twice! So go slow and clean everything well.
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Was oil leaking from the mating surfaces of the block and the pump or was it leaking from the weep hole?
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Frank75 clarified the situation in Post #2 -- out of the mating surface.
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my bad
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Actually the oil was coming from the weep hole. I hope to button everything up tomorrow.
And thanks everyone for the great feedback.
Frank
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Oil out the weep hole is vastly different than oil from the mating surface of the pump. If the oil is coming out of the weep hole, resealing the pump onto the block will not fix your problem. You'll have to buy the seal kit and rebuild the pump.
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as I and others have found, replacing the water pump seal gives varying degrees of success, which seems to be due to having or not having pits in the shaft, which itself is an expensive part. There's been some reported success with filling in the pits with like JB Weld
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Alas it looks like I have to rebuild the water pump. I do not really get how the oil seal in the water pump works as the weep hole appears to be behind the oil seal. I would think that the oil would always drip from the weep hole but I am not certain how the weep hole channel in the water pump body is routed. Back to wrenching tomorrow. Can anyone recommend a good source for the parts I need?
PS. these are not actual photos of my bike
Frank
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It's hard to describe but the weep hole passage is in between the oil seal and the water seal and so either fluid can leak through the weep hole. I also think that cross contamination would be very, very unlikely this way.
The space in between is where the shaft gets pits due to being exposed to atmospheric air via the weep hole.
I tried replacing my water pump seal twice and couldn't get it to seal despite following the write up instructions carefully. It's suspected this happens because the pits damage the inner seal while being installed. It seems that replacing the shaft (expensive) or trying to fill in the pits with like JB Weld of similar epoxy then sanding may work.
I gave up and bought a cheap used pump off a K1200LT on ebay.
There are some write ups around for it...sorry I've got homework to do and can't dig them up right now but search here or google.
My dealer at least had the water pump seal in stock. I can't remember if they had to order the oil seal. They'll have to order the newer retrofit parts if you have to update the spacer and impeller. I can't remember what the year cutoff is for that but if you've had yours apart already you can figure out which you need. If someone else doesn't reply of you can't find it I'll dig up that info
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Thanks - I will exam the shaft carefully once I pull it.
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Bumping this post with same problem--
My K1 just started leaking heavily out of the weep hole after an oil change. The shop said they noticed a small leak into the belly pan when I brought the bike in, but only some weeping. I never had oil under the bike. Within 24 hours after the change I had a small puddle under the bike. 10W-40 oil.
The shop wants to swap the oil/water pump for a total cost of $800 parts + labor. I see on RealOEM that a new pump is ~ $463. I'm struggling to understand why this oil leak spontaneously accelerated after a service. Thoughts?
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The dealer re-built my pump that I hand carried in, for less than $100. However, it was a K75.
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Some dealers will replace the seal, some won't. I replaced mine with a used K1200LT pump from eBay that was like $75. Been fine for like 20k miles
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Seems like a used DIY is the best option. Can you pull the pump with the bike on the center stand or do you need a lift? I'm sadly garageless now
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EURO - If you know how to use a hex wrench, have a freezer and some socket wrenches, I highly recommend you take a crack at replacing the seal on your water pump yourself. I did a lot of research on this site to see how to do it. I would add that putting the water pump parts and seals in the freezer over night greatly contributed to ease of pressing the seal in. Liberal use of Permatex gasket sealer on the mating parts works well. I think my DIY repair was under $200. Good luck and happy wrenching
Frank
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Can you pull the pump with the bike on the center stand or do you need a lift?
The center stand is enough.
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Excellent, I'll start looking to source a used pump
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Excellent, I'll start looking to source a used pump
The gear that drives the oil pump on the newer pumps has less teeth. If using a newer pump like from a K1200LT you need to also obtain that gear
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Good to know. I will try to resource a K100 4V one if possible, it should be identical.
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The dealer re-built my pump that I hand carried in, for less than $100. However, it was a K75.
You walked the pump in and the dealer rebuilt it for under $100 and you installed it, buttoned it up, no problems since? That is an awesome story. I'd prefer that over rebuilding the pump myself any day for $100. Did they check the impeller for pitting and say it was fine?
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Yes, no problem since. No mention of having any issues, pitting or otherwise.
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You walked the pump in and the dealer rebuilt it for under $100 and you installed it, buttoned it up, no problems since? That is an awesome story. I'd prefer that over rebuilding the pump myself any day for $100. Did they check the impeller for pitting and say it was fine?
I did the same in 2011 but my cost was $208 due to the shaft being pitted and was replaced.