I have a weepy / leaky right fork seal. I was wondering just how difficult these are to change and if I would need any special tools? I’ve never had a front fork apart, or really too much else. So, I thought what the hell I’ll just ask. Or, off to one of two dealers to get raped. They are so GD EXPENSIVE. I don’t have a clue what this job would cost. Anyone?
So if anyone can offer any advice on the above I would be grateful.
I was just led to Seal Mate website. A little tool for cleaning seal. I suppose $10.00 American plus shipping would be worth a try. Anybody ever try it?
Your best bet is to replace the seal, if one is leaking it would pay to do both of them and a good opportunity to replace the fork oil.
Have a look at this to see if you think you can do it yourself, I suggest you get the Clymer workshop manual and study that as well before doing the work.
Definitely a diy job. Just take your time. Ask questions as you go. If something feels stuck, step back and think first. Don't overtighten anything small.
This task list below works for the 81-84 R100. It's likely to be similar, in principles at least, ie, the sequence etc.
Before you start, whilst waiting for parts order delivery, try running a thin feeler gauge between the seal and the fork, angled so any junk might come out. Clean it off first and after. Also spray the tube down, clean it with a very fine steel wool, then inspect for stone chips.
No need to remove the forks, but you do need to drop everything off them. If your gaiters are split, now's the time to replace them.
Changing BMW R100's 81-84 fork seals/ springs/ gaiters/ oil.
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. If you want to replace the springs, you need to remove the large hex bolt at the fork top, therefore no need for point 2. That 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.
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 and the chromed fork tubes too. I use a fine wet and dry with wd40 to lightly clean the chrome..
9. Carefully lever out the old seal from the fork leg. I use a blunted straight screwdriver. Insert the cold new seal, use old seal to push new seal in. Do not scratch the mating surface of the seal.
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.
Conventional Fork seals have a garter spring which puts pressure on the seal to keep it in contact with the stanchion. The garter spring is not a continuous loop as there is a joint where one tapered end is screwed into the other. In the dim and distance past I have unscrewed the joint, chopped a little off the open end and screwed it back together again in order to tighten the spring.
Having gone to all the trouble to remove the seal it is of course false economy to do this spring tightening and it wouldn't work anyway if the seal lip was damaged. There might be rare circumstances where it's worth knowing that it can be done.
Attachments
Garter Spring Joint.JPG (43.45 KiB) Viewed 1025 times
This is amazing help guys. Thank you so much. I have the Clymer manual and you three above’s great advice. I can do this plus I keep the bike in my house and heated. Ya gotta baby the baby in winter in Maine.
Thanks again, I will let you know when I get joining on it. 2028 at the rate I’m going
Seldomseen wrote: ↑Fri Feb 09, 2024 6:21 pm
This is amazing help guys. Thank you so much. I have the Clymer manual and you three above’s great advice. I can do this plus I keep the bike in my house and heated. Ya gotta baby the baby in winter in Maine.
Thanks again, I will let you know when I get joining on it. 2028 at the rate I’m going
Just take your time and do one leg at a time lay it out as you pull it apart, take photos so you know what goes where and if unsure ask.
Seems there's a snap ring, a seal and a washer in there. That's different to the 81-84 R100.
A little fiddling to get them out, where care to avoid damage to the seating surface is important.
I’ve never had a front fork apart, or really too much else. 
So, I thought what the hell I’ll just ask. Or, off to one of two dealers to get raped. They are so GD EXPENSIVE. I don’t have a clue what this job would cost. Anyone?
