Ok, I finally managed to get my C15 forks apart. The oil seal holders were good and stuck. They're the model with the two part holder, the screw-on part and the upper interference fit collar.
Before I put them back together can someone confirm where the oil seals go? I had thought that on each leg one seal went between the holder and the slider and one went between the holder and the collar, but they were both fitted above the screw-on holder i.e. between the holder and the 'collar'.
Which is correct?
Thanks.
(While I'm at it has anyone used a more modern 'wiper' seal on their forks?)
Hi,
I have just taken my forks apart. i have the same setup as you. These are the later style of forks with 2 seals per stanchion whereas the earlier ones only had one seal per stanchion.
The collar is a slight interference into the threaded holder. There should be one seal fitted in the threaded holder, the other fitted into the collar per stanchion.
Finally I'm at the stage of rebuilding my C15 forks (for my Bantam green-laner project). All back together, well they will be when I find out where I put the springs! Oil seals fitted, stanchions a nice sliding fit.
I've got two questions:
What grade oil should I use? and ...
Is it advisable to wrap some PTFE tape around the seal holder threads?
Thanks
I think bsa recommended using some twine to seal the threads.
You do need to seal the threads or you will get a leak. PTFE tape is fine if you can get it to stay in place when you screw the collar on.
Oil grade is not too critical as the damping is quite rudimentary in those forks. You can also experiment with different grades to give a different damping feel but to be honest I've never noticed much difference. I use 10/30 or 10/40 car oil which seems to work. I also use this in the primary drive.
Thanks Adrian,
I thought there wasn't much else to stop the oil from leaking out. I'll try with the PTFE tape first plus some 15SAE oil.
Now, where are those springs?!
If you look on the fork slider where the oil seal cover screws on there is a small groove. Get some cotton string and wrap it into this groove so it is just proud then screw the oil seal holder down onto and over it. That method gives me an oil tight seal on my B40 and A10.