Fork seals - What's causing this?

[RaystheBMW]

When I disassembled, I just pulled the front wheel, fender, and caliper, drained the sliders and and removed the vertical allen screws on the very bottom inside where the axle goes. Then the whole slider assembly pulls down and away. I didn't disturb the upper tubes at all, except for removing the fill plug.

[some_guy]

Originally Posted by RaystheBMW

When I disassembled, I just pulled the front wheel, fender, and caliper, drained the sliders and and removed the vertical allen screws on the very bottom inside where the axle goes. Then the whole slider assembly pulls down and away. I didn't disturb the upper tubes at all, except for removing the fill plug.

This is what I was planning on doing, but if there's a alignment checking/adjusting procedure I'd go through that as well.

[chollo9]

Yeah, at this point, I'd "disturb" everything. Disassemble, clean & inspect, check tubes against a very good straight edge, etc. If the tubes are straight and everything else looks good, it would be worth checking the tubes with a mic, but wear usually is apparent visually.

I'd also only lube with grease upon reassembly, that way you'll know where the oil comes from if you get any.

[hoss18]

I know this is an outside chance but are the seals OEM or copies. Im only mention it because I had the expereince of buying a set from offline that I couldnt get to seal - always leaked from day one. Eventually pulled them out thinking something wrong with tubes etc but by chance measured the seals and they were about 1mm to big. Put OEM ones in and they havent leaked. Never heard of it before or since.

[H96669]

^^^ You may be right, my friend sure had "online copies" leak. But those look like OEM with some of the metal exposed. Not that good BMW leaving some metal exposed. Road salt got under the caps on my bike and rotted the metal. They sure leaked then....! I grease them now and inspect every year. Different bike....same seal design.

[Donkey Hotey]

Originally Posted by RaystheBMW

I didn't disturb the upper tubes at all, except for removing the fill plug.

You put the seals on from the BOTTOM? There aren't ANY bushings or anything else to interfere with doing that?

My money is that the seals were damaged on installation. I always tape around the top of the fork tube with electrical tape to protect the seal lips, then carefully slide the new seals down the leg.

There were no snap rings holding those seals in? Just friction? Something isn't right.

Edit: just saw pictures of an R65 fork tube. Yup, totally smooth on the bottom. I'd still bet on damage to the seals.

[boxerboy81]

Originally Posted by some_guy

This is what I was planning on doing, but if there's a alignment checking/adjusting procedure I'd go through that as well.

Google "Randy Glass fork alignment". It's extensive.

Changing BMW fork Seals/ springs/ gaiters/ oil, or how I did it on my 1982 model R100RS.

Nomenclature: I call the chromed tube the fork tube. The fork leg is the lower forged bit that the calipers attach to.

1. Put new seals in the freezer for 1 hour beforehand.
2. Loosen, remove, the top fork bolt to allow drainage and refill of fork oil..move h/bars to get to bolt.
2a. To replace the springs, you need to remove the large hex bolt at the fork top, therefore no need for point 2. That hex bolt is very tight and easy to round off. Make sure your tool fits well.
3. Remove the lower drainage small bolt. Allow oil to drain.
3a. Replace springs, loosely replace top bolt.
4. Disconnect brake calipers from fork legs...hang carefully, no weight or bending of the lines.
5. Loosen, don't remove, the retaining bolt at the bottom of the fork. Better leverage before the axle comes out.
6. Remove axle/wheel/front guard.
7. Now remove retaining bolt, drop fork leg down, leaving the fork tube on the bike. Remove old gaiters/boots.
8. Clean fork leg internals.
9. Carefully lever out the old seal. I use a blunted straight screwdriver. Insert the cold new seal, use old seal to push new seal in.
10. Slide upper gaiter spacer then gaiters onto fork tube.
11. Install fork leg with new seal carefully over the fork tube..
12. etc, etc...both sides
13. Reinstall drain bolt, refill oil, tighten top bolt.
14. wheels etc back on...
15. fiddle with the gaiter spacer, locate it into the breather tube on the inside of the lower triple clamp.
One hour max. Quicker the next time.

[Bill Harris]

Yes, the Randy Glass procedure is excellent and definitive;

http://aatherton06.home.insightbb.co...age/TITLE.html

--Bill

[supershaft]

Originally Posted by Bill Harris

Yes, the Randy Glass procedure is excellent and definitive;

http://aatherton06.home.insightbb.co...age/TITLE.html

--Bill

According to some. I know that I am by far not the only one that thinks otherwise.

[Bill Harris]

Of course not.

And your detailed and definitive procedure is published where?

Otherwise...

--Bill

[craydds]

Originally Posted by Bill Harris

Yes, the Randy Glass procedure is excellent and definitive;

http://aatherton06.home.insightbb.co...age/TITLE.html

--Bill

I'll put in my two cents. When replacing forks seals, etc., why would one NOT do the Randy Glass procedure? You have your forks disassembled. My contention is that the only way to reassemble them in the best possible alignment is by using Glass' steps. The reason I say this is because I have DONE it successfully - with one caveat. Replace the stock top plate with a precision machined TOASTER TAN; without a ToasterTan (or San Jose, etc.) top plate the Glass procedure may not work as well. In other words, it is impossible to get the forks in "perfect" alignment without a precision top plate, but the Glass procedure is not faulty. Caveat #2 - the above statements may apply only to the bikes with the flat stamped steel top plate. I have no experience on the bikes with a stock BMW forged or machined upper clamp; I do not know if this applies to RaystheBMW's R65.

[woodgrain]

Originally Posted by hoss18

I know this is an outside chance but are the seals OEM or copies. Im only mention it because I had the expereince of buying a set from offline that I couldnt get to seal - always leaked from day one. Eventually pulled them out thinking something wrong with tubes etc but by chance measured the seals and they were about 1mm to big. Put OEM ones in and they havent leaked. Never heard of it before or since.

My neice had a K75 which had a similar experience. She ordered on-line and the seals never did...seal that is. I just thought they were really old and hard.

Woodgrain

[supershaft]

Originally Posted by craydds

I'll put in my two cents. When replacing forks seals, etc., why would one NOT do the Randy Glass procedure? You have your forks disassembled. My contention is that the only way to reassemble them in the best possible alignment is by using Glass' steps. The reason I say this is because I have DONE it successfully - with one caveat. Replace the stock top plate with a precision machined TOASTER TAN; without a ToasterTan (or San Jose, etc.) top plate the Glass procedure may not work as well. In other words, it is impossible to get the forks in "perfect" alignment without a precision top plate, but the Glass procedure is not faulty. Caveat #2 - the above statements may apply only to the bikes with the flat stamped steel top plate. I have no experience on the bikes with a stock BMW forged or machined upper clamp; I do not know if this applies to RaystheBMW's R65.

Most of it isn't necessarily wrong. It's just that most of it can be done without all that fuss that article calls for. Plus, as you were alluding to, most all of the article does not apply to R65's or any other bike with "real" top trees. It's a very long winded article that really takes a long winded counter point which I pretty much have done in the past. Other than the article making people aware that the forks need to be lined up, I don't care for it. For the most part, my critique centers on this: Block and tackle? Most all of what they are 'cold forming' can be accomplished simply by loosening and tightening all the fasteners involved in different patterns and even amounts. That is if you have straight parts to start with and there are ways to determine that.

[Big Bamboo]

Originally Posted by Bill Harris

And your detailed and definitive procedure is published where?

Not wanting to start an arguement, but I always just use the method outlined in the factory manual... Including the "bouncy" part before tightening the axle clamp bolt. Works fine for me!

[Bill Harris]

That is simply the procedure for reinstalling the front wheel. The Glass article is for for checking the forks for straightness and alignment. And for straightening and correcting the alignment if they're not.

--Bill