cleaning fork oil seals

[rjs987]

Not all fork oil drips are caused by worn or damaged fork oil seals. Sometimes it is from grit that gets into the seal.

Noticed after my ride on Saturday to the store that there was a drop of fork oil on each side of the front tire. I inspected the forks and the brakes and found that the design of the brake mounting to the fork prevented any from getting onto the pads or the disk. Today I dug out the cleaner tool that made from an old plastic milk jug using a genuine SealMate tool as a pattern. I pulled down the dust seal and then ran the tool up between the seal and the fork tube and ran it all the way around and then cleaned off any oil that seeped out doing that and put the dust seal back up. I have upside down forks so it is the bottom part that moves up and down into the upper part. I did this for both sides. The dust seals on my AK have a spring/ring to hold them tight to the moving tube of the fork as well as the ridge holding them into the stationary outer tube.

I know it is unusual for both forks to develop a leak from grit that gets into the seal or from wear damage to the seal. But it seems to me more likely that it was from grit due to some roads I was riding during my long trip over a week ago. I was riding through some road construction so there was a LOT of grit and some gravel I had to ride on. Next will be to go for a ride to see if that took care of it or if I have to replace the seals. Fork seals are wear items that usually don't need to be replaced very often, but can need it more often depending on road surface conditions. I've had the forks on almost every bike I've owned leak a little oil once during ownership. Cleaning took care of it in every case so far. The first time I did this I didn't fix the drip but then found out I didn't first pull out the dust seal and that was what I was cleaning. After pulling out the dust seal first there is the oil seal farther into the outer fork tube and after cleaning that seal the drip stopped for me. Will have to see if that worked out this time as well.

[rjs987]

Went for a test ride today to check if the drip on the forks was just grit in the oil seals (which I cleaned in the previous post) or if it is something more serious.
Rode almost 16 miles. Thought one road I took would be a good test having a lot of compression bumps, but that one is being resurfaced now with a new layer of asphalt and only one lane open with a "follow-me" vehicle. That's the kind of situation that I think caused the grit to get into the seals in the first place but this time the surface I was riding was much cleaner. Another road that was on for about 3.5 miles was still that bumpy surface with the compression bumps. Not really pot holes yet, but bumps in the road that go straight across side to side at regular intervals. This was a concrete road that is used by gravel materials business trucks all the time so the surface doesn't last all that long.

I figured these conditions would really work the front forks constantly and give them a good test if there was still a leak or if it was really just grit.

Turns out it was just grit. I stopped about 5 miles along the ride to look at the forks and there was just a little oil left over from behind the dust seals so I wiped that off. I rode the rest of the way and on that really bumpy bit and checked the forks again after parking in the garage. No more oil on the forks. Clean a shiny.