Fork legs cleaned, painted and new seals

The bike had been sitting for a few years after being driven in winter conditions and the fork legs both had weeping seals.

I took the wheel and the brake calipers off (after I had already removed all K1 plastic), took off the brace plate which holds the brake line splitter and removed the fork legs out of the frame.

Make sure to work on one leg at the time, don’t mix parts. First take the top off, which is under slight spring pressure. It won’t launch itself at speed, just press down a bit when you unscrew it.

I then removed the spring, the spring guide, the spacer and the top shim.

Then I emptied them, let them drip out for an hour so most old oil was out. I then rinsed it with clean paraffin a few times, and gave it a final rinse with some clean fork oil. That left them oily but clean.

Next step is to get the seal out. On the K1 forks this is a bit fiddly as they don’t use normal circlips (the ones with the two holes), but a simple flat ring which is diagonally cut. It can take anything from 2 minutes to half an hour to get them out…

Once out just move the inner leg up briskly and the seal will come out. Don’t throw the old seals away yet…

Put them in a vice between some wood or soft cloth, and remove the large allen screw at the bottom to separate the inner and outer parts. If you just want to change seals this is not necessary, but I wanted to spray the lower halves.

I put the parts in numbered bags, and took the picture below for reference. Mobile phones can be useful….

Fork legs after disassembly and before repaint
Fork legs after disassembly and before repaint, note where the paint has been damaged by the plastic mudguard on the left leg

I subsequently cleaned and degreased the lower halves, and sprayed them like I did with the radiator (previous post). Same process, same paint.

They came out rather well as can be seen in the picture below that I took just before re-assembly, it shows all parts of one leg.

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Fork parts, from top: spring cap, spring, lower fork leg, spacer, shim, dust cap, top cap, circlip, ring under seal, bottom screw, seal, inner leg

Assembly is not difficult. Check the inner legs for pitting, and make sure to get rid of any sharp bits before putting the new seal in. You can use a small hammer to softly tap edges of pitting flat and/or a whetstone to make sure they won’t damage the seals.

Then first put the inner and outer leg together again, then use some thin machine oil or fork oil to oil the new seal. Put the shim in (hollow part on the bottom), then carefully shift the new seal in place. I cut the old seal in half with a hack saw and used the halves to push the new seal in its proper place. You know when it is seated when you can see the groove where the circlip has to go.

Finally put the circlip back in, make sure it is seated in the groove all around and put the dust cap on. Done.

Finally the spring, spring cap, spacer and shim can go in (in this order) and the top cap can be screwed on. I did not fill them with oil yet.

 

 

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