Originally Posted by Gene_Chapman
Is there a quick and dirty way to replace a leaky fork seal or will I have to pull the plastic and tank to get to the culprit? I have the seals and the dust boots, just need to see if I can complete this task in an hour or two, or if it is going to be a day long project
Thanks in advance for any help on this project!!
Just to clarify a few things:
There are seals
which keep the fork oil in, and wipers
which keep dirt from contaminating the seals - these are both BMW parts
and SHOULD be replaced on both forks.
The fluid MUST
be replaced since it is contaminated
and probably congealed (not what the repair manual says) and will lead to premature failure if you don't use new fluid. You should also clean out the legs completely
with spray brake fluid cleaner, allow to drip and air dry upside down and then swirl some oil in the tubes to remove all traces of the brake fluid cleaner. Discard this oil by allowing it to drain upside down. I used "fork oil" but any ATF should work just fine - all it does is lubricate.
Common jack oil (contrary to what I have said earlier) would probably not
be a good choice since it might "froth". The capacity of each leg is 16 ounces.
Wipe down the outsides of the tubes with a new microfiber towel lubricated with oil
BEFORE installing the legs and new seals. If you feel ANY snags, burrs, dings, pitting, etc. it will need to be replaced. Lubricate the inner surfaces of the seals with oil as well. After the legs are installed wipe off any residual oil on the tubes with another clean microfiber towel before allowing them to compress.
If you want to dramatically increase the life of the seals a dust boot is a MUST. This is NOT a BMW part
but they are very common at MC shops and especially dirt bike and 4 wheel drive shops. If you're a cheap sonomabeach like me you will not
need the wipers if you install these, the savings will probably pay for the boots. Putting the wipers and boots on is total
overkill. ..but I did it anyway...
I used a black accordian boot, sorry I don't have the part name or number. Luckily the diameter of the ends of the boot fit perfectly
on the top of the tubes and the leg, although I did need to trim off some of the pleats on the bottom with a utility knife since they were too long. I further secured the boots at the bottom (the top of the boot was very tight around the tube) with BLACK nylon wire ties (white ones will snap in very short order) to keep them in place.
Prior to riding make SURE
the boots don't bind on anything - they may touch the sides gently on the top at full lock - this is nothing to worry about.
I've included a few (fuzzy)
pictures below to show you what the installed boots look like.