Fork Rebuild...DIY or BMW shop?

[Froader4life]

My front forks are completely dead as far as dampening. Seals are shot and not even sure there is fluid left in them. I was quoted about $220 from a local BMW factory motorcycle shop. I have been looking around for a rebuild kit but all I find are places that sell what I need piece by piece and I'm not totally sure what all I would need. What should I do?

[johnny]

the first thing i would do is drain the suspension fluid and replace it with honda ss8-10 suspension fluid... wipe the forks down with automatic transmission fluid... clean out any debris between the seal and the fork... go for a ride and see if the seals leak... if so... i would replace the upper and lower bushings and the seals... replace the suspension fluid and give it a go...

j o

[Kyle10]

Got a Clymer or Haynes manual? If not, get one.

Take a look at what's on YouTube; it'll familiarize you with the principles, process and parts. Don't worry if they're not specific to your bike as they're all the same, essentially (just make sure you're not confusing your forks with USD forks).

I installed progressive springs, replaced the fork seals and generally reconditioned the forks on my '85 K100.

*Make sure you obtain a pair of decent fork circlip pliers. A MUST.

And while you've got it apart consider installing a pair of fork gaiters. Duck has 'em for a great price.

[552255]

By the time you order/buy seals and bushings, oil...$220 may not be out of line.   Its not an easy job, and messy.  Depending on the tube, it can be a pain in disassembling them. (after front wheel/fender/caliper removal)  The 'circlip' can take a long time to pry out.  A vise to hold the tube is near necessary....you'll need to fashion a seal driver to seat them in. 

Definitely put gaitors/protectors on....you don't want to do this very often.   Get the BMW seals, not the cheap Ebay listed (pyramid?)ones...they don't even fit.  Best of luck, I've done mine twice.   Try to fill them up maybe first...and there is a method of using a feeler guage/thin piece of metal or plastic, to get under the existing rubber/seal and lift out any gunk, by working around/under the seal.  I have had success to clean out a good seal using this method...

[mystic red]

Naw, go with the Rancho's... way cheaper than BMW's and just as good.

[tg4360]

Not a difficult job on my '87 LT.

None of the brick forks are super complicated.

If you can get your hands on some 35mm film stock, slide it in under the seal edge and the sprocket holes may catch and remove any smutz that's in there and cure a weapy seal (if it's not a cut or ding or scratch on the fork tube).

TG

[gavthirtyseven]

Just done mine last week and not exactly the easiest forks to work on. (92 k100rs)
That circlip holding the seals in is a pain in the behind to remove, takes 2 pairs of hands and a pick and a small flat bladed screwdriver...
The Allen bolt at the base of the forks wouldn't budge using my air impact wrench so took it to a local bike shop where he had a larger compressor and more serious looking impact wrench. They popped straight out then.
The pyramid seals are 1.5 mm or so too tall so replacing the clip to retain them is impossible. I trimmed the bottom with a Stanley knife blade and they now just squeezed in. Phew! :musicboohoo:

Oh yeah I used a 4 inch piece of 2inch diameter plastic plumbing pipe cut in half lengthways to seat the seals. I carefully tapped this with a hammer all the way round to drive them home.

Those are the main pitfalls I guess, not huge but frustrating if you weren't expecting them. I have a clymer manual but for an oil and seal change I didn't need it. If you're doing it yourself get a friend to help remove the circlip and get the biggest air powered buzz gun you can for the lower bolts! :2thumbup: :2thumbup:

[Scott_]

  The pyramid seals are 1.5 mm or so too tall so replacing the clip to retain them is impossible. I trimmed the bottom with a Stanley knife blade and they now just squeezed in. Phew! :musicboohoo: 

I hate to say it but you may as well get yourself some BMW seals to have handy as those pyramid seals will start leaking in about 6mo or less.   BTDT.

[gavthirtyseven]

Yeah, but I'm cheap! And it doesn't get much cheaper than free... :hehehe