R80/7 Rear Main Seal Leak

[Airbear]

Phil, here's a simple tool that will pull the RMS to its rightful place:


RMS.jpg

Thanks Charlie, how thick did you make it?

I think it's 16mm MDF. Doesn't matter much, anything that is stiff enough would work. I don't recall the thread size. Take one of the bolts to your favourite fastener supplier and get some 50mm bolts, nuts and washers.

[jackonz]

Thank you all for the info on the rear main oil seal, seems there are various options re this seal, on one site I looked at the seal comes with a sleeve in it to hold it's shape and this site said it was the new OEM type double lip seal, another site shows the same item and says its a pattern item.

Rob Frankham some time ago sent me info re installing the seal dry or lubed (thank you Rob) and upon reading it again the OEM seal needs to be pre formed using the installation drift, not only that but if I read it correctly its a single lip seal.
So am now wondering if I should just go and get am OEM seal from BMW NZ and as for the drift I can turn one up in the lathe at work, am not paying $85 US for one.

Thoughts please I have as yet not pulled it apart and am not going to ride it until its fixed.

[jackonz]

The rear main seal has to be installed bone DRY (and the flange perfectly clean) or it will leak like a sieve as soon as the engine is started. The correct depth is flush with the case. No special tool required if it's tapped in squarely.
I've seen one or two oil pump covers with almost invisible hairline cracks around the screw holes cause leaks in that area.
If in doubt, start the bike and check for leaks before re-installing the transmission.

Hi, thank you for your detailed info, I have been back on to the supplier of the seal I fitted it was as far as the part number is concerned supposed to be the latter neoprene seal 11111338342, according to service bulletins I have read it is to be fitted dry but with a forming installation tool, I contacted the supplier who now tells be to put a smear of oil on the seal outer and seal lip when fitting.
I have watched YouTube of Brooks Airhead garage fitting them dry and the tool looks like a flat plate same story when I look at Boxer2Valve.

I have not as yet ordered a replacement seal and now reluctant to purchase from this supplier in the UK again, its going to be expensive as I will need to replace flywheel, clutch and drive shaft bolts as well as I did ask them if at the time fit it dry or oiled and they said dry and now they are saying lubed.

I did 20 years in a engine reconditioning shop and never had such conflicting information on a simple seal install.

I would value your vast experience on this.

[gspd]

.... its going to be expensive as I will need to replace flywheel, clutch and drive shaft bolts as well as I did ask them if at the time fit it dry or oiled and they said dry and now they are saying lubed.

You can safely re-use the flywheel, clutch and drive shaft bolts if they're in good condition.
Put a drop of blue loctite on the driveshaft bolts.

[jackonz]

.... its going to be expensive as I will need to replace flywheel, clutch and drive shaft bolts as well as I did ask them if at the time fit it dry or oiled and they said dry and now they are saying lubed.

You can safely re-use the flywheel, clutch and drive shaft bolts if they're in good condition.
Put a drop of blue loctite on the driveshaft bolts.

Hi, thanks what is your opinion if any on seal supplier and should I use a forming tool, I know you responded way back to install dry.

As for the oil pump cover I did check this out and it looked fine, mine has the later hex bolt type cover not the countersink screw type.

[gspd]

I always use only the BMW OE seal # 11 11 1 338 342 after a few leaks with some other suppliers.
Install everything bone dry. It might sound counter-intuitive, but clean and dry is the only way to go.

Before installing the seal in the case, if your bike has the later type light ring gear with a separate spacer ring (the part the inside of the seal rubs on) remove it from the crank to install the seal and then push the spacer back in after. Make sure the inside end-play spacers stay in their pin holes.There should be a o-ring inside the the earlier heavy flywheel or inside that later spacer to prevent oil from seeping out around the bolts. I vaguely recall that some years/models did not have that o-ring but they should have one. If there's a groove for it, make sure there's a o-ring in that groove. If the spacer seems stuck on the crank you can pull it out with vice grips after applying some heat to it. You can 'preform' the seal by simply test fitting it on the flywheel or spacer but it will 'form' itself either way.

[jackonz]

I always use only the BMW OE seal # 11 11 1 338 342 after a few leaks with some other suppliers.
Install everything bone dry. It might sound counter-intuitive, but clean and dry is the only way to go.

Before installing the seal in the case, if your bike has the later type light ring gear with a separate spacer ring (the part the inside of the seal rubs on) remove it from the crank to install the seal and then push the spacer back in after. Make sure the inside end-play spacers stay in their pin holes.There should be a o-ring inside the the earlier heavy flywheel or inside that later spacer to prevent oil from seeping out around the bolts. I vaguely recall that some years/models did not have that o-ring but they should have one. If there's a groove for it, make sure there's a o-ring in that groove. If the spacer seems stuck on the crank you can pull it out with vice grips after applying some heat to it. You can 'preform' the seal by simply test fitting it on the flywheel or spacer but it will 'form' itself either way.

Hi again, I have the earlier heavy flywheel and yes I did replace the O ring and cleaned out the grove for it, I did lube the O ring to ensure it slipped on the crank without getting a nick in it.
Maybe I just need to purchase the so called forming installation tool and be done with it or turn up a flat plate to push it in square as per Brooks Airhead otherwise the bike is running brilliantly, what do you think?

Cheers.

[jackonz]

Following corispondence with the supplier of the seal I installed it has transpired it is NOT an original seal but a pattern item, so I am now trying to obtain a genuine BMW seal.

So far in NZ no stock at all.

[jackonz]

Well after waiting an age I have finally received the new OEM rear main seal, having looked at it it matches what is in BMW service information 00 053 88 (2324) and confirms that what was supplied originally to me was a discontinued type.

So I have questions in that it states in the above bulletin "If the shaft is rounded or chamfered sufficiently, the seal can be pushed on. If the shaft is NOT rounded or chamfered, you must pre-shape the seal prior to installation. the desired shape can usually be obtained by pushing the seal on to the drift to install it".
Now my question is as I have purchased an install tool from BMW Motorworks that had what appears to be a step that I assume match the seal face on the flywheel, if I am correct then I can use that to pre-form the seal, question is how long should I leave it in the too for to form it, am thinking I will push the seal in then leave the tool in there for whatever I need to then install the flywheel. Or should I put a small chamfer to the leading edge of the flywheel seal area.

[mkj]

Oh lucky me, I too have just attempted the replacement of my rear main seal and I may say with out success. I tracked it down to a groove on the fly wheel boss, I have not cured the leak yet as I put a second hand flywheel in, on an already used seal. My seal came on a plastic former and had cartoon instructions . The instructions say to leave the seal in place for 4 hours before starting the engine, chamfer nothing but get a thing strip of fine wet and dry paper and clean up the surface where the seal runs then polish it with metal polish get it as shinny as you can. I have manged to polish the grove out of my original flywheel and will refit it with a new seal come winter.