Fork Seal Replacement -- Procedure Clarification

[Ben_Carufel]

Hi guys,

This morning I took the fork sliders off and replaced the seals. I followed a few writeups and the Clymer manual, but now I need a little clarification...

The two hex/allen bolts that hold the sliders on (the ones that you can't access with the axle in place, I think they were an 8mm allen?) loosened up really nicely this morning. However, people seem to keep saying that to tighten them, I'll need to depress the inner thingies (with the 19mm wrench flats) at the top of the fork tubes, remove a circlip, and access a bolt inside the fork tubes in order to re-torque those 8mm allen bolts properly. Is this the case, or is that only a step needed if the fork was farther disassembled?

I'd love to skip that whole step if possible, and I'm just totally confused about whether that's necessary for just a fork seal replacement?

Thanks for any input...I'd like to get her buttoned back up Friday morning and take her for a maiden voyage.

[Barry]

I'd love to skip that whole step if possible, and I'm just totally confused about whether that's necessary for just a fork seal replacement?

You do have take the slider off the stanchion to change a seal and so you will need to remove that Allen screw.

However so far (and I've had the forks apart several times) I've manged to do it without using a socket and long extension down through the stanchion.

What I do is leave the spring in place which keeps the damper rod piston under some tension so that there is some resistance when you try to undo the Allen screw. Not enough though or the Allen screw would have been too slack. If you are lucky though you can shock it free with a gentle tap from a hammer on the Allen key. Pushing the slider up at the same time will help by adding more spring pressure. Sounds like you may have done it the same way.

I confess I put it back the same way which means I don't know the torque applied but my forks don't fall off and I'd know if the screw came loose as the fork oil would leak out and it never has but bear in mind that to do it by the book you need that socket and long extension.

[montmil]

Hi guys,

This morning I took the fork sliders off and replaced the seals. I followed a few writeups and the Clymer manual, but now I need a little clarification...

I'd love to skip that whole step if possible, and I'm just totally confused about whether that's necessary for just a fork seal replacement?

Thanks for any input...I'd like to get her buttoned back up Friday morning and take her for a maiden voyage.

Look upon this as another opportunity to develop BMW maintenance skills.  Or, it could be a way to ruin your Friday ride time.

Yep, the fork springs must be removed to tighten up that big ol' allen screw. You'll need about 14-inches worth of 1/4 drive extensions to reach the damper rod top nut down in the lower fork legs. I think it's 14mm... I think.

Any way, you'll hold the damper rod nut whilst tightening up the now way far away allen screw. A helper helps.

BTW, depressing the "inner thingies" and removing the big circlip thingy is easier done with a helper. With the top allen screw still in place, have your helper press the cap down as you use a small, flat blade screwdriver to tilt the circlip. Then, you may extract the clip with needle-nosed pliers. Don't let it fly away!

An allen/hex socket on an extension will be helpful for your assistant and also provides you with some work space.

And do be cautious as pressure is released off the fork springs. Boing! Hello, bloody nose.

May as well swab out the fork lowers while you have them free. You'll likely be amazed at the fine dust and fork oil sludge that's been living in the bottom of your fork legs.

Please do properly torque the bottom allen screw before riding off. It's considered bad form to have the fork lowers fall off as you pop a quick wheelie leaving the local cafe.

Perhaps Saturday might be a better target for a ride? I've been there. Don't go back too often.

Monte

[Bob_Roller]

The socket size for holding the damper inside the fork is 13 mm .

Just had a set of forks off for seal replacement in the last month, so I'm a bit current on it .

[Ed Miller]

I would do it like Barry said.  If you can get that lower bolt tightened up without taking the top parts off, good.  But if the damper rod turns before the bolt tightens up, then you will have to pull out the top plug, spring, and use the long socket with extension to hold the damper rod still.

[Ben_Carufel]

Just to close out the thread...

I decided to bite the bullet and take the circlips out of the top of the forks to access the 13mm bolts. Wasn't too hard at all. I was able to put the allen bolts (the fork oil fill bolts) back in their places and push down with the appropriate allen bit on a socket wrench, then hold the wrench against my clip on bars with one hand while fishing the circlip out with a right angle pick with the other hand.

Once I had those out, the top caps of course came right out and I removed the springs to photograph them. Putting it all back together was simple, once Mike and I figured out the fork alignment issue (to be addressed soon).

[Mike V]

Wanted to let everyone know how we finally figured out Ben's forks were different lengths at full extension.

With the wheel, axle and after-market fork brace removed we tried to install the axle.  The axle slid through the right slider with no problem.  But it met solid resistence trying to enter the left slider.  We guessed through process of elimination and close inspection the left slider seemed to be extended a small amount further than the right.  Ben applied slight pressure on the bottom of the left slider with a jack until the axle slid through.  With the axle inserted into both sliders (no wheel) I had Ben mark the left tube above the wiper with a felt pen using the top of the wiper as a template or straight edge.  We then removed the axle relaxing both fork sliders.  The top of the wiper ended up at least 5mm below the ink mark on the tube with the axle removed.  Never experienced this before, personally.