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Output Shaft Main Seal Installation Tooling - Your Thoughts

5K views 18 replies 8 participants last post by  jzeiler 
#1 ·
Greets!

I have a proposal to consider when replacing the famous main seal. And a couple of questions.

I just ruined one piece main seal ($44 + shipping) because it was late at night and thought hammering it in with a wooden tool would work. Never mind, when it was in, I discovered that on one side the seal was too far inside. I then installed the clutch housing, filled in the old oil, topped it to make sure is enough to cause some pressure and with the engine lowered at an angle waited one night. Needless to say, the next day I found the oil leaking. Ergo, one brand new seal busted.

I found myself awake at 5am trying to google the mysterious BMW 11 1 630 tool and what could be used instead, thought about using M20 nuts welded together over a disk with a hole in the middle and what not and then it dawned on me that I already have the tools. Not giving away, if you like riddles pause here, look at the picture before reading on.

I practiced this with the spent seals (I have 2 now) and it really works. One has to only push the new seal the right way over the housing spline shaft, then screw in the housing (w/o the O-ring and the "stop disc" in place). The housing will push on the seal evenly and the pressure can be controlled. The housing cannot push the seal too far in. For the last millimeter on the way in, the housing can be taken out and the spent seal can be used in reversed position (outer lips facing out) in between the housing and the new seal to GENTLY work in the new seal until flush. Of course, checking again and again is necessary and only little thrusts at a time are allowed.

Questions:

1. Did I just reinvent the wheel? (I searched the forum for answers first)
2. Can inserting the housing spline shaft into the new seal where it belongs, then take it out again, then put it back erode/damage the inner Teflon lip? (it sounds such a sensitive area :grin:)
3. Can the "fine tuning" step be skipped and the installation done directly including the "stop disc" (the plastic disc between the housing and the seal)?

At 3. the idea is that the "stop disc" is actually designed to "rub" against the seal surface all the time.
 

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#3 ·
The pipe flange works fine, in fact anything that will drive it in evenly and flush with the housing and no further will work. The tool you mention can be made from plans on this site if you want to go that distance and not use the more readily available pipe flange. The key is to make sure it is even all around and no deeper than even with the case. Any deeper and the bearing will chew it up. Here is a picture of the actual tool made by a friend. It was made from drop stock or it would probably be the most costly ever made as it is solid Teflon. My recommendation for those who do not have a machine shop handy and readily available stock of the adequate size is to go to home depot and buy a pipe flange and a short stub of pipe. Works as well as the $200 Teflon. :smile: Lube the outside and leave the seal lip dry.
 

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#4 ·
The pipe flange works fine, in fact anything that will drive it in evenly and flush with the housing and no further will work. ... Works as well as the $200 Teflon. :smile: Lube the outside and leave the seal lip dry.
Thanks to all for the replies! Yeah, having a lathe that can machine even wood and/or plastic only would be a blessing. For the main seal, the clutch housing, its M20 nut and thrust ring do the job very well using the 30mm clicker. I found it hard to hammer the seal in, it is really tight and needs a bunch of thrust even if oiled. The M20 nut does that very smoothly.
But for the 4 gear box seals, I can only come up with makeshift tools. I'm thinking to ask the private BMW specialized shop nearby if I can take the gearbox to them to punch the seals in. I expect them to have all those BMW 22 4 XXX sleeves and drifts on page 23.7.
 
#7 · (Edited)
I'll lend you all the tools that Clymers says to make plus that pesky main seal driver you talk about. It has a hollow drive shaft handle so the out put shaft from the engine can enter. It is the correct OD for the seal edge and it has a small rim for proper depth. It cost me 17$ to mail them. You use them then mail back with my 17 bucks inside. I also include a viton 19x4 mm Oring.
I generally am ambivalent about changing out that rear main seal when the leak is because of the Oring. It is a very high quality seal and should last many thousands of miles. snipesb(at)cnw.com
Also a thin one layer of electrical tape is needed so the splines will not cut the inner lips of the seal whey you install it. Maybe even cellophane tape. And I believe it is supposed to be lubed but check on that.
 
#8 ·
I'll lend you all the tools that Clymers says to make plus that pesky main seal driver you talk about. ... And I believe it is supposed to be lubed but check on that.
Thank you so much!!!

Let's not go the trouble yet. I placed a call with the nearby BMW specialized moto-shop to see if they would put the seals on the unmounted gearbox if I take it to them, still waiting for them to answer. Meanwhile I'm waiting for the parts. I already got a Viton ring too, found an online store (The O-Ring Store LLC) that sells them by the piece.

I think you're right about covering the splines, the manual mentions sleeves for that. The seals are sensitive on the shaft side. Definitively oiling the seals. Someone mentioned to not oil the Teflon lip on the main seal because apparently it's supposed to create a "layer" of sorts on the shaft. Honestly, given the "all oil" environment, I don't see how that lip can be prevented from ever seeing oil. The manual states "oil the sealing ring" w/o a warning to not touch the Teflon lip.

Safe ride!
 
#10 ·
Two of the three seals you need to replace on the trans have a pretty critical placement or they will leak. Make sure the shop you are taking it to has experience with these or you will be pulling things apart again. The slave cylinder seal has an oil opening on the side of the case so a little too deep and it will leak potentially contaminating the new clutch you just put in. It is also pretty easy to damage the case walls where the seal sits in removing this one. The input shaft is fairly forgiving but the output shaft has an oil hole in the shaft a few thousandths from where the seal lip rides so again, just a hair too deep and it will leak. Splitting the case and driving the seals out from the inside is the onlyway to remove without destroying them so if you get them wrong, you need new seals to try again. You can see the placement on mine where the new seal leaked from being too deep and the second replacement after making the seal driver to set it properly. With the seal removed, you can see the hole. The drivers make much easier work in setting these in the correct position so I would ask if the shop has the proper ones.
 

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#13 ·
Two of the three seals you need to replace on the trans have a pretty critical placement or they will leak. Make sure the shop you are taking it to has experience with these or you will be pulling things apart again.... The drivers make much easier work in setting these in the correct position so I would ask if the shop has the proper ones.
Thanks a bunch for the info!! This is very helpful. Wondering if this should go in its own thread. Well... Anyway, the shop I took the gear box too has been doing BMWs for quite a while, they do K-bikes all the time. Nonetheless, I will check one more time before putting it in. Don't want to actually open the box, will fill the transmission oil and let it stand for a while, see if anything comes out, can also rotate the gear a bit while at that.
The clutch cylinder looks good, didn't leak so far, will drill the weep hole before I buy a new one. Read that the oil can creep along the push rod if the cylinder leaks. Not really into buying a new cylinder at this time though.

Here's the thing though: even the main seal behind the clutch housing was leaky, and there was oil everywhere in the intermediate flange room, the outside wall of the engine, the wall of the gear box, even on the outside of the flange, for whatever reasons the old clutch was dry. It slipped because it was worn off. I can spin the old disc with my bare hand while the old clutch is assembled and tightened with clamps. That was the reason that made me open up the whole thing.
I'm not saying that oil contamination is not possible. It just didn't happen this time. One thought, it may have been the dust from the clutch disc that was accumulated on the walls that collected the oil and kept it from creeping onto the clutch. I cleaned that area and there was a LOT of goo on the walls.
 
#14 ·
Progress report:
The approach using the clutch housing and the old nut to push in the seal worked. It's not easy, but I refilled the old motor oil and topped it on purpose and it's been holding for 2 days now (have to replace the motor oil anyway and will also service the pan with a new seal).
The housing by itself drives the seal only down to a point, then I had to place the old seal between the new seal and the housing (outer lips facing towards the housing), and use a rubber hammer to continue punching it further in. The fitting is really tight and it takes quite some force to do it. I worked in steps, removing the housing many times and look to not drive the new seal too deep inside.
At the end, for the last 1mm(which doesn't matter really, there's enough room between the two housings left after tightening the nut) I gently and patiently "touched" it with the rubber hammer around the perimeter until it was flush with the engine housing.
So if you don't have a tool or cannot make one, this approach works. Most important, for the first 5 or so mm, the housing does a great job driving the seal in evenly.

The gear box is at the shop right now, hopefully I'll get it back today.
 
#17 ·
Final report: It works!

The method proposed in the initial post works. It's not the easiest thing to do (amazing how much pressure that seal needs), but when one lacks the actual tool it is a good alternative. After pushing in the new seal only using the housing and screw in the OLD nut and ring as far as it went (about 2/3 way in), I had to actually use a bit of hammering with a rubber hammer on the housing to make room for the old seal to fit in so the nut can grip the thread again. Still the advantage is that the seal was already in and evenly aligned. One could also cut some of the outer walls of the old seal to make it narrower. That would be nicer, then the nut would become usable again. Anyway, the job is done. I refilled the old oil and added some extra, left the engine "hanging" overnight to see if anything comes out, then I tightened the new clutch in (see pics). The bike runs again and the new clutch feels godly.
One more thing. This is a huge job with the bike half in the air. My recommendation to everyone is order all parts ahead of time so you have them. Once the decision to open all that stuff is made, this is an opportunity to do more than just the clutch:
- Main seal and O-ring
- Clutch diaphragm, disk and housing cover replacement (it is worth the $1000 for the parts)
- Engine output shaft nut and thrust ring (the old nut should not be reused due to the self-locking feature - the thin hairlike cut in the sides)
- Any bolts that show wear and tear and/or cracks
- Input, output and clutch slave cylinder shaft seals on the transmission
- Replace transmission oil
- Clutch slave cylinder replacement if necessary
- Drilling the clutch slave cylinder weep hole (it doesn't hurt and if it helps, even better, done easier with the transmission detached, see photo for spot, I was lucky to hit it by just eyeballing it)
- Check all splines, grease with Kluber Microlube GL261 (if you don't have the OEM BMW grease)
- Check all tightening torques and all nuts in particular if bike was serviced before by unknown mechanics (I found 3 US standard nuts, some lazy idiot mechanic forced on the M12 bolt between frame and transmission and the two M10 bolts of the Paralever)
- Clean everything so you can spot oil drips later
- If you're not sure, had oil drips before, renew/replace the oil pan seal (e.g. using Permatex Ultra Black 82180 3.5oz), replace engine oil (a chance to switch grade), oil filter (e.g. Bosch 3330)
- If you replace the engine oil, don't overfill (the max line is under the lower lip of the main seal when the bike sits level), mine took about 4L / 4qts of oil
- Replace rear drive oil, check rear drive for visible signs of trouble (see other threads)
- Since your bike is already almost naked, do that brakes and ABS unit fluid flush as well, in particular for the iABS3 units (2005 upwards)

Good luck!
 

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