Greetings!
I have enjoyed the great discussions on this forum for a few years now. In fact, when my 85 k100rs started looking coolant this site directed me to instructions and parts for replacing the oil and water seals. After looking through several instructions and consulting a few experts, I replaced both seals. When I put the pump back on oil started leaking through the weep hole at a steady drip. The parts i used had been sitting on my shelf for several years and the bottom of the pump housing where the oil seal sits was a little pitted, but not too bad, so I thought that one of those issues might be the problem.

I then bought brand new seals and this time applied a little permatex on the bottom of the oil seal to fill in any small inconsistencies that exist on the bottom of the housing and to hold the oil seal in place while (carefully) hammering in the water seal. After replacing the pump there is still a drip from the weep hole at the same pace as before.

What could the problem be??

The shaft and housing are both in great shape except for the minor damage on the bottom of the housing. I have included a picture of the housing below. Any help on this would be greatly appreciated!

G'day, Looking at the picture of the housing, is it possible that a tiny bit of the old oil seal is still stuck in there??? Looks similar to my housing when I replaced the seal. Don't ask how I found out a bit of the old seal was still stuck in there.... Good Luck  Cheers Tom

I use a small cup brush in a drill to make sure that the housing is totally free of shite. I'm sure other people have better ideas than that!

Thank you both for responding. Do you mean the black part in the outer ring on the bottom of the housing? I think you are mostly seeing shadows as the trench is pretty deep. It did take me a while to work out the old rubber from there, though. I ended up using a pin to carefully get it out. I did just check and there was a little "gunk" in the little trench just now but not sure it explains my problems still.

A question: how is the oil seal supposed to sit? All instructions I have read say to grease it and tap it in until its "seated". But what does this mean? The fact is the oil seal can move around after its tapped in because its not a tight fit the way the water seal is. So how does it work? I was thinking that after you seat the water seal it would press the oil seal against the bottom of the housing, but that doesnt seem to be true. After I put the water seal in the oil seal was still moving around underneath the water seal. Is that right?

thanks again for all your help. I'm trying not to get too frustrated!

If the seal can move about then the pump is now a very artistic piece of scrap. You may be able to get someone to put a bronze bush in there but that would be a couple of hours work and would be as expensive as a new pump.
Either way you are up for a new or good pump at the least. I would be buying a new one unless you can be sure a used is in good order and even then I would be putting a kit through it.

I have been looking at the original picture and I will stake my life there is some leftover in there from the previous seal. There is a steel surface with spots of rust.
The highlited area is the steel surface and will come out.

Here is a better pictures of the housing. There might be some coloration in the uneven surface from the old seal but I dont think I can get anything else out of the bottom there. I had previously gone at it with 000 grade steel wool and got out as much as I could. I considered taking a more serious approach to evening the surface down at the bottom but it seems like that would make my problem worse.

Even if I could get it all out it seems like you are saying there is a problem with the oil seal moving too much. The consistent leak after both seal changes makes me think the oil seal is not seated properly and is what is causing the leak.

What could result in the oil seal having too much room down there?? This is very confusing to me.

perhaps this pic might help

notice the oil seal land depth in the casing below the weep hole exit



good luck

RicK G wrote:I have been looking at the original picture and I will stake my life there is some leftover in there from the previous seal. There is a steel surface with spots of rust.
The highlited area is the steel surface and will come out.

agree rick, I think I can see the shoulder of the oil seal area behind that what appears to be washer bonded in by an old rubber seal ?

The most recent photo bennyfoofoo posted clearly shows a second layer of metal...looks like it was sanded down to the point where it's going to be difficult to remove.
The surface imperfections at the very bottom of the pump are inconsistent with how the surface should look after removal of the oil seal. 
The photo clearly shows a second layer of metal...
If you don't remove. It, you will most likely have a leaking pump.
Sanding it might not have been a good idea.
Perhaps use an implement with a pointy end to remove it.

Good luck

If anyone on the forum has a water pump housing in pieces without an oil seal, then they could measure through from the oil side to the shoulder where the seal should sit. That measurment will show if there is part of the old seal still in there.

I agree with Rick and Charlie that it looks like there is not enough depth from the weep hole to the pitted surface.

I get the old seal out using a longish thin dowel in from the oil side. Need to be very careful not to score the bore.

Cheers

I don't understand the confusion. If you enlarge the photo bennyfooffoo posted showing a view of the water pump from the top, you can clearly see a second layer of metal and underneath the pitted rusted surface is the water pump.
I am using an iPad.....pls enlarge the photo and all will be revealed...hope this helps....
Cheers

Ok it took me a while but I think I now understand what everyone is saying. What I think is the the bottom of housing you all think that is actually part of the old oil seal? I guess I wasnt thinking that was the case because I have an additional housing thats all rusted out and it has that piece in it too. I thought it was part of the oil seal and tried to remove it but ended up deciding that it was indeed part of the housing. I just tried to remove the old one again and it really doesnt seem to want to come out. 

If thats the case them I'm not sure Ill be able to get it out of the newer housing. It really seems attached to the housing. Any further suggestions on how to remove it?? Ill start seriously considering it now that I understand what everyone was saying.

Also, if it is the case and it does come out then the gap between the oil seal and water seal will be even greater, correct? If im already having problems with the oil seal moving around due to too much space that then it will only make it worse.

thanks for being patient with me!

I made a special punch to get at that seal and have used it a few times. It is a length of 10mm or 3/8 stainless steel about 9 inches long with a sharp bend at the end so as to get over the shoulder and behind the seal. You need to shape the end specialy with a grinder so as to get over the shoulder at the end of the bearing surface where the shaft runs and give it a solid hit but be careful not to damage the bearing surface, if the bar is smooth it will be OK.
If you need a drawing because you don't understand my description then ask and I will do one. Keep at it as we aren't done with the tricky bits yet there are lots more ideas.

Benny, I don't in any way intend to disparage you mechanical aptitude with this suggestion, but you may wish to do what I did when it can time to address weeps/leaks in that pump.  Send it to a qualified BMW mechanic.  A large part of the cost of repairing the pump is pulling it off the engine. You've already done that. The pump is in hand.  Why not box it up and send it off for a BMW shop to deal with?
That worked for me.

Hi Benny

The oil seal is moving around because there isn't enough depth in the pump for the seal to be seated properly.
The used oil seal is stopping you from properly seating the seal.
The official approach to this situation is to place the pump on a flat surface water side down and used a 5 mm screwdriver. Insert the screwdriver into the pump from the oil side, that is the side which attaches to the engine block. insert the screwdriver at a slight angle and use a small hammer to drive it out.
The aim of this exercise is to drive it out of the pump, not pull it.
The BMW workshop manual includes a photo which might make my instructions easier to understand.Carefully insert the screwdriver and try to catch the edge of the seal. A few light taps with a hammer will drive it out.
Check your progress with each tap of the hammer.
Try not to scratch the housing. 


Hope this helps.
Cheers
Gabs

ok I got the rest of that seal out. I am so surprised that its not the bottom of the housing. How embarrassing!!  haha. thank you all so much for pointing that out. I will tried another go with rebuilding the pump now that the oil seal can be properly seated.

I know that removing the seals often breaks them but I am going to try to use the new ones that I previously installed and removed. They both looked to be in good shape and if I need to get new ones again ill be an expert at taking the pump apart and putting it back together now.

I agree that maybe I should have had a professional take care of this job but I am eager to learn about working on the bike and would love if I could fix this problem myself.

thanks again for all your help, ill let everyone know if it holds fluids in a few days.

Hi Benny

Well done!!
Another example of how this forum can benefit its members.

Great news Benny.  I cant say I have made that mistake but I sure have a record of many others.

good suggestion Gabriel

good work there benny ...cheers 

hope it all goes well ...this time

So far so good!

I put around 30 miles on it this past weekend and nothing leaking . I am so excited!!!

thanks again for everyones help and patience! this forum is truly amazing,

Ben