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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: ermach on January 21, 2014, 11:10:06 AM
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I've got an 87 K75 with 50k ish? miles on it with what seems like every bit of rubber or seal taking a dump on me. It's a texas bike, and bavarian rubber doesn't care for the heat much. I've got what seems to be a leak from the area of the alternator. I was lubing splines and want to get these leaks taken care of as well, and I've already gotten the trans off. I can't tell if the seal behind the clutch is leaking as well. I'm confused about what the rear main seal is. Is it behind the clutch, or is it the seal behind the alternator? It seems like there is a lot of oil on top of the transmission, possibly leaking down into the clutch area, which is why I'm not sure if I want to buy the tool and pull off the clutch and all. I'd like to have a cleaner bike, and peace of mind, so in other words, help!
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The rear main seal is behind the clutch housing, see #1 on the diagram here:
http://store.bobsbmw.com/microfiche/BrowseParts.aspx?GroupName=Clutch&MBike=51752&GroupID=21 (http://store.bobsbmw.com/microfiche/BrowseParts.aspx?GroupName=Clutch&MBike=51752&GroupID=21)
If it was leaking you're probably have oil coating the inside of the bell housing and all over the clutch parts. I sure did have that when my RMS was failing and it oiled up the clutch plate so I started getting slippage. There's also a little O-ring back there (#11) that oil can get past...that little bugger was the cause of another oiled clutch because I damaged it when reinstalling.
I remember that my buddy Mike got the clutch off and the rear main seal replaced without any special tool so it must be possible to do. He jury-rigged something, I just can't remember exactly what. I'll call and ask if noone else has that info. But if you have the transmission off and see oil you should probably just plan on replacing the RMS, you're halfway there anyway. If there's oil in the bell housing, you have to determine where it's coming from. First question would be whether it's gear oil or engine oil. If it's gear oil it's probably coming from the rear where the transmission is. If it's engine oil, it's probably coming from the front where the rear main seal is.
If the inside of the bell housing is dry, then I'd pull the clutch pack off, inspect the clutch disk, get clutch bolts, lube it up with Guard Dog, put it back together and look for the problem elsewhere.
So you have engine oil pooling on top of the transmission and dripping down the transmission case and onto the ground? It's not gear oil, and you don't smell gear oil coming from anywhere else?
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what i have seems strange. I definitely had oil inside the bell housing, which made me think I needed to do the main seal, thanks for clearing that up for me. What I also have is oil on top of the transmission. It's not exactly pooling, more of a thin, dirt catching coating that looks like it's coming from where the alternator is mounted. I wasn't sure if that was even a possible leak point. I did some more reading and it seems like I can do the clutch without special tools, but lining it up by eye and using the trans to make sure it's aligned. It's hard to tell on this bike, because so much is coated in oil/dirt. It seems to be leaking up front too, by the hall effect sensor, so I have that to deal with later. I don't remember any clutch slipping, so I guess I lucked out there. I do have a fair amount of drive shaft wear, so that sucks. looks like I'll get the main seal, o ring, nut and bolts and button it back up, and see how it goes
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Does the oil on the trans case smell like oil or gear lube (sulphur)? There is a small vent on the top of the trans housing near the alternator that would allow excess trans fluid to come out. This might be your culprit. Other than that, unless oil is coming out past the starter, or you have a crack there aren't many other possible locations.
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More than likely the rear main seal. Front oil leak, I would bet is the water/oil pump. You might look at the "weep" hole for oil/antifreeze. Might order all parts together, save shipping.
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I'll check the vent hole on the trans, I'm going to pick up the main seal after work. I'll also look closely for some sort or crack. I'll have to clean off the front and check the weep hole. seems like water pump season at my house, honda element and k75. thanks for all the replies.
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ther than that, unless oil is coming out past the starter, or you have a crack there aren't many other possible locations.
Well, there's the clutch pushrod seal, which has been the culprit for me in the past. If you have gear oil in the bell housing, I'd replace that pushrod seal too. I hear other people say it's not too hard but it was a bitch for me to get that seal on right. Read in excruciating detail here -- http://www.motobrick.com/index.php?topic=5183.msg31947#msg31947. (http://www.motobrick.com/index.php?topic=5183.msg31947#msg31947.)
If you've got oil in there, you probably have an oiled clutch plate and maybe it hasn't become noticable yet. If it's oiled then it will slip, it's just a matter of time. The dealer tells you if it's oiled you need a new clutch plate, but I and other brickers have reported good results cleaning it off thoroughly with degreaser. I also lightly sanded with 400 grit between cleaning passes...don't know if it really helps but it was recommended to me by a trustworthy source.
BTW does your bike have a crankcase breather hose? I remember that can get very gunky and oily but I don't know if it can actually be the source of any appreciable fluid accumulation.
Also, I picked up a clutch alignment tool and valve adjustment tool from Kenneth Lively for $40 for both. see here: http://www.motobrick.com/index.php?topic=5075.15;wap2 (http://www.motobrick.com/index.php?topic=5075.15;wap2) . I was using a screwdriver wrapped with ducttape, that would probably work. I would definitely use something other than my eye, though -- any misalignment can cause vibration.
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A real plus for Kenneth's tools, work like a charm and are really inexpensive and save hours of fooling around.
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You can build the rear seal tool from wood, there is a post I found somewhere on the web or buy the tool from A&S I think. I can find exact link if needed. With the RMS costing $30 and clutch parts hundreds or more; best to get the proper tool IMHO
I am about to do the same job when all parts and tools arrive. The RMS replacement is like no other seal I have seen. Just a thin material. On other cars and etc I'm used to are a rubber with a spring to seal the rubber to the shaft
This seal look fragile.
Anyone have experience installing? Tips?
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After seeing Kenneth's prices, I figured it was worth it to get the clutch tool. Apparently Ft Worth BMW has inventory tracking issues and didn't really have the seal after all. At least I'll get M & M's with my order this time. I just changed the crankcase breather tube, but haven't had the bike out in months. I had issues back in the summer which ended up being a loose motronic connector, I killed my battery and starter relay, replaced the wiring under the tank, and put on some tires. I bought the tyco relay off ebay for $26
http://www.ebay.com/itm/BOSCH-TYCO-AUTO-RELAY-75-A-AMP-12-V-volt-QUALITY-HEAVY-DUTY-HIGH-CURRENT-/300879378680?pt=Motors_Car_Truck_Parts_Accessories&hash=item460dcef8f8&vxp=mtr (http://www.ebay.com/itm/BOSCH-TYCO-AUTO-RELAY-75-A-AMP-12-V-volt-QUALITY-HEAVY-DUTY-HIGH-CURRENT-/300879378680?pt=Motors_Car_Truck_Parts_Accessories&hash=item460dcef8f8&vxp=mtr)
which has worked out, plus saved half off euromotoelectrics! I didn't get a chance to look at the bike yesterday, so I'll still see if it's motor oil or gear oil. Dealer is def not an option for me, plus it makes me feel a lot more confident with what's going on with my bike when I fix things myself. I'm getting closer and appreciate all the help
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Use the block of wood, and gently, using lots of patience tap it into place. Dead blow hammer helps. I am pretty sure there is a link on Motobrick, but here is one also:
http://www.ibmwr.org/ktech/mainseal.shtml (http://www.ibmwr.org/ktech/mainseal.shtml)
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BTW don't mean to flood the thread, but I seem to remember an issue with getting the clutch housing off to get to the RMS. Some other special tool...I can't remember exactly. That's what I was talking about before when I mentioned my buddy Mike. I'm bringing this up now because I might have to do it when I get the transmission off my other K75 for the spline lube soon and I'd like to be prepared if I need to get to the RMS.
So -- short question -- any special tools required to get the clutch housing off to get to the seal?
RE: OEM parts providers -- I don't know about Fort Worth BMW but I can recommend Bob's BMW for OEM parts. Billion Dollar Bob -- I've never had bad advice or a bad shipment, the parts staff has always been knowledgeable and professional and I've gotten so much value from the microfiche on his site I have no problem plugging his establishment. Bob is very friendly, too -- he's there a lot and always greets me when I go in.
It's good to have a relationship with the local dealer if the dealer has anything to offer except sales and post-sales service. But IMO it's better to have a good relationship with a local old-school BMW wrench if you can find one and get the parts from Bob's. The young generation at BMW dealers generally doesn't know jack about 2V K-bikes and are contract staff that get paid per job and are only 'trained' on newer models. BMW jettisoned it's old school wrenches back in the early 2000s and adopted the contractor business model. It pissed me off. I had some good friends at Ride West BMW in Seattle that got sacked for a bunch of know-nothing noobs.
My $0.02.
Van
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