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Is fork seals a do it yourself job????


leeinmemphis

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Hey everyone,

 

I noticed on a ride today that I have one of my fork seals leaking pretty good. I was wondering if anyone knows what all in involved to replace them? I am sure that I can remove/replace the forks but didn't know what would be involved to actually replace the seals.

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Yes. It's easier on a GS because of the lack of bodywork, but not too bad even on an RT. The left seal on my 1999 RT started leaking about 60 days after I bought it. I solved the problem by changing the fork fluid, and replacing with a 75/25 mix of 10 wt fork oil and ATF seal conditioner. That was 20,000 miles ago. Not a hint of leakage since. I did not remove any body work. The only "special" tool I needed to buy wass a 22mm spanner to prevent the tube from turning while I loosened the top nut.

 

Long thread here: http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=675618&page=1

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... wondering if anyone knows what all in involved to replace them? I am sure that I can remove/replace the forks but didn't know what would be involved to actually replace the seals.

 

As Seldon has linked, it is a very straightforward job

see: http://www.ukgser.com/forums/showthread.php?t=97873

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And if you do take the fork bridge off, ensure everything is trued up correctly or you may well encounter increased front tyre wear. (see post #588148 for the technique to do the correct set up).

 

Andy

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Thanks for the info everyone! I will try to call beemer boneyard this afternoon to see if they can send me a seat of fork seals. Thanks again!

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Thanks for the info everyone! I will try to call beemer boneyard this afternoon to see if they can send me a seat of fork seals. Thanks again!

 

The ones that really do all the job are ~ cheap, like 8$ both. The dust seals are expensive... Mine were not cracked and did not changed them. No leaks 16k km's later ;)

 

Dan.

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There is a bit of a cheat that you can try before doing the replacement. Some folks take a small piece of cardboard, like a business card, and after lifting the dust cap, work it into and around the seal to clear debris. Then put a tablespoon of automatic transmission fluid in on top of the seal and replace the dust cap. The ATF will swell the seal. This works sometimes.

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Can the dust cover be popped up while the forks are still on the bike? If so I may try that prior to pulling the fork tubes.

Yes the covers are easy to lift up. Even better than using cardboard/paper is finding an old photo negative or some type of thin film like that and lube it with a thin oil.

Then slide it between the fork seal and the fork tube. And work it all the way around the tube. This stopped a leak for me about 12k miles ago.

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I was amazed at how easy it is to pull the fork tubes on a Telelever suspension -- far easier than traditional telescopic forks. Once I had the fork tubes out, I was even more amazed that the whole thing has the necessary rigidity to function properly -- it's a very clever piece of engineering.

 

And, because pulling the tubes is so easy, I don't understand why anyone would want to go to the extra trouble to remove the fork brace and pull the sliders. If I remember right, I used a 100cc syringe and about 3 feet of vinyl tubing to suck out the old fork oil -- which was kind of gross, black, and with a bunch of junk in it. Even if you don't have a leak, it's probably worth the trouble to change the oil after 50,000 miles.

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You do not need a syringe to empty the sliders on the bike. There is a drain screw at the bottom. Just pull the front wheel axle to access it.

 

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leeinmemphis

I just got in from picking up the seals. I'm going to try to do them this afternoon. Thanks again everyone!!!!

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leeinmemphis

Just wanted to say thanks to everyone for all the info! I changed both sets of seals out. The first one took about an hour to find a tool that would remove the seal and the second one took about ten minutes. Thanks again!!!!!!!

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  • 1 month later...

This is an old thread, but it really helped to shorten the seal replacement process. My R1150RT with 37K blew a seal on my last ride so it was time to replace the seals in both forks. The GS models would be somewhat easier than the RT as there is good access, but on the RT you are working down in a hole between the fairing and the stem. I bought a seal puller; too long. 'Cut the handle off about half way and it works now. After removing and hanging the bars, and pulling the front axle, I drained the oil and it was really ugly! Work the tube up and down to flush the oil, and pull the tube. I looked down the fork and there was lots of trash and deposits down there, so I used a length of 3/4" pvc and a funnel to pour some kerosene into the fork to flush the bottom. I did this twice, and then used some paper towels rolled up and inserted into the end of the pvc to wipe the bottom of the fork clean. It looks great now. Seat the new selas with a 32 mm socket and a 10" extension with a little help from a rubber mallet, snap ring in and dust seal on, bolt up. and away we go. I think it's worth while to go the extra step to clean up the forks inside and change the oil if you are going to put in new seals. This was a very helpful article!

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Just did the seals on the R during winter down time. Mixed in some seal swell with the new fork oil (20% of volume). Also installed fork boots on the sliders. have had boots on the K for it's entire life. Keeps the sliders free of seal damaging crud/dust/rain spray/etc...

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My mech did it diff.He removed the wheel,remove nut to paralevel ball joint,then dropped lower forks down as an assembly.Took him 30mins.though to get all the gunk out of bottom of tube.Job took 2 hours,but most of that was spent disconnecting fork lights and removing gunk

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  • 1 month later...

If I was going to do this job myself again I would definitely do it from the top. To remove the handlebars and top end of the stanchions so that you can swing the top yoke out of the way is dead easy. And now I know there's a drain plug I won't need that length of pipe and big syringe.

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So How do I search for a specific post #...like post #588148?

Do you know what? I don't have a clue! I assumed that you could just call that numner up in the search directory, but it seems not.

Anyone got a suggestion how to search for a specific post number (like in this case #588148)?

Andy

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  • 3 months later...

Cut out the side of a plastic bleach bottle (after the belach is gone of course!)... and make a tool about an inch wide and a few inches long.

 

It works better than a business card because it is much thinner. while cutting it, make a hook on one end. That is the end to push past the seal. Work your way around the seal and slide it back out and the hook should bring out any dust or lint like debris that may be causing your leak. It worked on a Honda Nighthawk I used to own...

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Morning leeinmemphis

 

As mentioned above with your fork seals being almost 10 years old you should think about eventual replacement but that can be an off season job or even wait until they start leaking again.

 

My guess is there is nothing actually wrong with your seals as 90% of those leaking seals on the BMW boxer are not bad seals but mostly old washing soap or road dirt working down under the dust excluder then contaminating the lower oil seal lip area.

 

In most cases that area of the seal to fork tube can be cleaned & helped to re-sealed again without taking the front end apart. As long as you didn’t lose too much fork oil then cleaning & re-softening your stock seals usually works pretty darn good.

 

On the BMW boxer there are actually 2 seals on each side to deal with, the one you can see when looking at the forks is not really the seal but just an upper dust excluder. That one you see isn’t the oil seal as the oil seal is under that top dust excluder.

 

To clean & re-soften your existing seals—

 

First use a small (nick free) screwdriver & simply pry the upper seal (dust excluder) out of the lower fork leg & move it up the fork tube (work around it’s outer edges to do this) . That will expose the actual fork seal underneath.

 

Then put a drop or two of auto trans fluid on the lower seal right at the seal to tube interface to lubricate the seal lips.

 

Then use an old 35mm film strip (works best), or t-h-i-n piece of plastic, or my favorite a .002” feeler gauge. Lubricate whatever you use so it doesn’t scratch the fork tube or scratch the seal, then (carefully) work that down between the lower seal & fork tube. Carefully work that all around the seal to work any dirt or old soap out of the seal area.

 

Now put the bike down on it’s wheels (or side stand) to compress the forks a bit. Then slide the film strip (or what ever you used) between the seal & fork tube) that will let the air pressure inside the lower fork tube out & neutralize the pressure.

 

The next move is optional but as long as you are there this will go a long ways towards eliminating seal leaking & condition older hard seals.

Get some automotive Power Steering stop leak (basically concentrated seal conditioner). Then slide that film strip (or whatever you used) in between the seal & fork tube (to hold the seal lip out a bit) , then use wire, or eye dropper, or (I use a small syringe without the needle) to put a bit of that Power Steering seal conditioner between the seal & fork tube. Work all around the seal to be sure the entire seal lip is coated.

 

Now grab the upper fork tube & give it a spin (about 90° is good) as it floats at the top so can be spun.

 

Now slide the upper dust excluder back down & seat it.

 

Then (optional but I do it) is to pry the lip of the dust excluder out away from the fork tube then dribble in a bit more Power Steering seal conditioner between the upper dust excluder & lower fork seal. If you do this you will probably find the upped fork tube wet for a few rides so wipe it off after every ride for few rides.

 

By doing the above I have had very good success at stopping fork seal leaks on the BMW 1100/1150 & some have never started leaking again even for years afterwards.

 

 

 

 

 

 

 

 

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You do not need a syringe to empty the sliders on the bike. There is a drain screw at the bottom. Just pull the front wheel axle to access it.

 

 

The '02 RT does not have a drain plug. I just finished this job myself and dropped the tubes out there was a fair amount of gunk in both tubes, even the one that wasn't leaking yet.

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Hi Rocks, pretty sure the '02 does have a drain plug, but probably hidden under grime that fills the hole in the axle apparture.

Andy

 

Nope, At least not mine. I had both forks fully removed ALL dirt and grime was removed... there are NO drain plugs. If you look in a Clymer manual both kinds are listed.

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