R100 Rear seal

[goodguy]

With my first 100 I replaced the main seal incorrectly because I didn't remove "main seal ring guide" wasn't aware that it was to be removed. Have found out that it has to be pulled off, does anyone have the tool for this job, I don't want to attempt levering as would I feel damage the seal housing.
Airheadcool

[bmwr100s]

Hi, have restored a 1977 BMW R100S I think I have the same problem as I changed the rear seal which is leaking, I don't know about a O ring on the fly wheel bos, any chances posting a photo of the fly wheel boss so I can also do some research on this as I need to sort it out myself, appreciate all the help I can get on this one.


Regards Steve.

[goodguy]

Hi Steve...Up to 80 the 100's had the heavier flywheel, believe that I am correct in saying that the "main seal ring guide" was part of the flywheel, so it all came out as one piece, the lightened flywheel that I have does come off easily, though the centre piece still remains attached, there must be a tool somewhere that pop's this off (do ensure that your crank is blocked when messing in this area !) I now have two 100's in my shed awaiting rear seal replacement...Any advice out there?
Google Chris Harris BMW motorcycle mechanic, has many clips available.

[bmwr100s]

Thanks for that, will start digging deeper, cheers Steve.

[jono]

Hello Guy
I have a tool for replacing the rear main seal, is that what you're after?
JonO

[goodguy]

Hi Jon...am wanting to know how the "centre boss that spins within the rear seal" comes off, also after a clutch alignment tool.

[wightman]

Hi Guy. Sorry, didn't read your post properly, before diving off onto the other forum. I don't know how to get that rear main seal out if its still stuck down the hole, without the special tool. I remember reading in another forum that the biggest reason for rear main seals continuing to leak, is insufficient flattening (cleaning)of the mating part of the boss on the flywheel (ie the seal is not mating on a completely plane surface)

[goodguy]

I don't have any leaks or problems, I just want to remove the "main rear seal guide ring" it also has an internal O ring. Once this has been removed, I replace its O ring, put in the rear seal, then then push this centre piece back in, on with the flywheel & away I go.

[goodguy]

Jon sent me an article, the part that I wish to remove is called the ..main seal guide ring.. am still having trouble removing this, Q; is there a tool that assists in the removal of this ?
At present I seem to be doing a lot of hitting & prising, just doesn't seem right. & not much is happening.

[nickschober]

try googleing it there are lots of things on youtube etc , no im not trying to be smart

[goodguy]

Have done a fair bit of googling, saw Jon's article that he sent....which say's a bit of tapping & levering & all is good....Doesn't seem to be the case with me, this would be a fairly common job, what does a mechanic do in this situation?....There has to be a tool of some sort.

[goodguy]

I got it....I got it....The trick was to use heat, I will require another seal guide ring as this has been bashed a bit...Heat tap heat tap, then with holes off centre screwdriver to help lever off.
Thanks for all your tips everyone.

[Goldie1]

Hi Guy the earlier flywheels where the seal runs is part of the flywheel and wears a groove in it they us to get a machinist to turn that part of the flywheel down and sweat a stainless steel sleeve on but I don't know about the later ones.I have never owned a clutch aligning tool what I do is assemble the clutch on the flywheel do the bolts just over finger tight put gearbox on Move it around so it goes into the locating lugs slip it off then tighten try again then box of and do clutch bolts to correct tension ,always use new bolts on flywheel and clutch. I know it sounds a bit of a hassle but it doesn't take long.

[goodguy]

Thanks for that Goldie, am going to get an alignment tool off Jon, though I understand what your saying regarding getting away without one, I always use new bolts. My bike that I rode back in top also has its gearbox out, havn't taken its clutch off yet, gave it a tough clutch 3 years ago, though after that ride I guess it would be rather worn, so that will be another rear seal job in the near future, should be getting quiet expert at this.

[Goldie1]

Guy I don't know if you have done it or not but you need to put centre punch mark or paint on fly wheel and crank so they line up correctly when refitting other wise you won't get the timing right