BMW’s Begging for Attention: Leaky Fork Seal

I guess I take the BMW’s reliability and practicality for granted and sometimes she reminds of that.  Case in point, a few weeks ago I noticed the upper right fork seal had apparently started to leak.  The bike is 13 years old with 27,000 miles but that probably not why the seal began to leak.  BMW fork seals are pretty darn durable and if one starts to leak it’s usually because something got past the dust seal and into the oil seal creating just enough of a void for oil to escape.

I’m going to guess that I may have actually been the weak link here in that I’ll put 900 miles a month on the bike going back and forth to work in just about any kind of weather condition and if the forecast for the coming week calls for rain I won’t bother washing the bike.  Well, it’s rare that there’s not rain in the forecast during the spring and summer here in the South so… yeah.  I allowed the BMW to get pretty filthy now and again, washing it only when it was so filthy that I felt guilty.  So I’m going to venture a guess that the build up of grime on the slider allowed some grit to migrate past the dust seal that caused the oil seal leak.

I picked up a new fork oil seal, guide washer and bushing at BMW of Atlanta yesterday — I think it was $36 for the three parts — and found myself with enough time to install them today. Thankfully, it’s not all that difficult to pull the upper sliders out of the fork lowers on the R1100S.

Step 1: After pulling off the lower belly fairing I was able to use my J&S motorcycle lift to unweight the front and rear wheels so that the front fork could rotate freely. I learned the hard way after I first bought the bike that you don’t want the full weight of the motorcycle on the front wheel when disconnecting the forks from the upper triple tree.20160731_101243Step 2: With the bike on the workstand, there are only three bolts that hold the upper fork stantion in the triple tree: two pinch bolts (one in the tree and one on the clip-on) and an alignment bolt that connects the clip-on to the tree.


Step 3:  As I looked at what I had to work with I decided that the upper right body fairing would need to come off so that I’d have better access to the top of the lower fork so off came the white plastic fairing.

Step 4: With the fairing off and the right tools, changing the forks was pretty easy.  The dust cover was popped off with a flat-bladed screw driver, the snap-ring was easily removed with a pair of needle nose pliers, a seal removal tool lifted the oil seal out in moments,  and the alignment washer lifted right out.  However, I had to do a little farmboy engineering to get the bushing out, making a DYI bushing remover from a couple of washers, bolts and a 10″ long bolt: yeah, that’s not going to make the highlights but it works really well.


Step 5: In the upper half of the photo are the new alignment washer, bushing and seal.  I probably should have replaced the dust seal as I found cracks around the upper edge of the seal.  I’ll probably just do that at some point in the future. Regardless, with the cir-clip out, it was time to swap the old parts for the new ones.


Step 6: With the new bushing, washer, seal, cir-clip and old dust seal in place it was just a simple matter of re-inserting the slider in the lower fork, then putting the clip-on on the slider and then re-inserting the upper end of the slider in the triple tree.


Step 7:  No photo here, as it was just a matter of putting the fairings back on the bike. However, I will confess that I gave the bike a good cleaning while I had it on the lift and the the belly pan off since that opened up access to the motor and make cleaning wheels, etc. a lot easier.

Here’s hoping that did the trick!




About TG

I've been around a bit and done a few things, have a couple kids and a few grandkids. I tend to be curmudgeonly, matter-of-fact and not predisposed to self-serving chit-chat. Thankfully, my wife's as nice as can be otherwise we'd have no friends. My interests are somewhat eclectic, but whose aren't?
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