Vindicator
New member
On another note, the holes in my cartridges were fairly sharp on the inside, enough to tear lint from a shop towel. Vindicator, maybe this is the cause of your oring leaks, nicked orings as the lower edge of the holes is right on the edge of the PFP bore. A small piece of #400 on my finger cleaned it up nice.
Thanks, I'll do the same to mine the next time I service it
The question of why some of these cartridges stroke to different lengths still remains. I can't see how all the air would be purged without a slight overfill, and if the taper in the PFP rod allows a blow off of air and excess oil to the top of the piston and ultimately the outer chamber, why should there be a difference between forks? Also why such a longer compression of the spring on assembly. Is it working against the top out spring to an extent?
I also find this quite intriguing, I'm not sure but I think the air should come out by the PFP shaft recess the first couple of times you stroke the rod. At this point the fork should not be using the full length of travel because there's more preload than it should and the piston is toping out against the cap. Only after the air/excess oil is expelled the fork would have the full travel again. This does not mean you can't have more than 7mm of preload, the limit should be the recess/full travel . After putting together one of mine I had this scenario on 4/5 strokes of the rod. I could see the the piston up and down through the holes reaching as much as the bushing. When compressed, small amounts of oil escaped between the o-rings and would come out through the holes. When flipping the cartg upside down small quantities of oil would come out, possibly escaped from the recess. In the end there was a noticeable decrease in the force needed to push the rod and when fully compressed I could now see the upper o-ring of the PFP only .
I had seen the recess but I did not quite understood its need until Leo mentioned how he bleeded his cart because both of my carts are bleeding oil by the orings. Again, I'm not sure of this but I think no oil should be allowed to pass through the PFP o-rings because this will affect the desired preload . Bad PFP o-rings is the only explanation I can think off to having some forks with different preloads, assuming they were serviced with the same amount of oil . Any ideas ?
Next time I will also dismantle the PFP to take some metrics and do some math related to the max preload it takes.