Fork oil change Help please

[ivorbaines]

Would appreciate the benefit of experience. I'm in the process of repainting bottom yoke and leg lowers, thought while legs are out will change oil and clean insides, having referred to Haynes and BMW w/s manuals it appeared that the screw in bottom of leg is for draining oil, wrong. Having broken the torque on the cap head screw it just rotates and will not even tighten back up. Pull stanchion out of slider and there is a piston inside that the bolt is holding, problem is the piston is just out of reach below the top edge of the slider, need to restrain piston so that bolt can be fully removed, anyone over come this problem?

[winger]

Have to say you lost me a little(not difficult!) what screw are you on about?,i've had my forks down but there's no screw,just pulled the fork tube out and tipped the leg up and drained the oil out.

Looked in my S workshop manual and there no sign of it in there either,try takeing the seal out and see if the the piston drops out.

[gus]

Hi
I know the one your talking about.Bottom of fork leg under the machined hole for spindle.I did the same,but i was trying to seperate the internals so i could get the fork tubes anodised.If its really loose,then try and spin the hex head whilst pulling on the rachet slightly.Do this whilst holding the fork leg upside down.I didnt get mine really tight,just enough to take up any slack.Has,nt caused a problem since.The oil drains out of the top of the tube.Refilling,early forks 175ml a side.I dont the amount for the later type forks.
all the best
gus

[ivorbaines]

Dismantled at last. The bolt in the bottom of the slider has a "O" ring seal on it, the piston in the slider is actually a plastic tube about 30 mm diameter with light alloy end caps, the lower one is threaded and its into this that the "drain" plug screws. Used a windy impact wrench, following some advice.
Thanks for the help.