Halo tophased,
I hope I understand your problem correctly.
Just try to warm up with the fork with a hot air gun. When everything is hot, maybe you can push down the cap with a clamp.

Good luck, Karsten

Hallo tophased, hallo Georg

I wouldn´t beat on the top of the cap with a metal hammer, because it´s very easy to damage the chamfer, where the Oring sits.
Georg´s second proposal is much better, but you need a srew with, if I remember correctly, M7x1 thread.

Best regards, Karsten

Hi,

that's quite normal.
First loosen the upper srew of the fork bridge, just a bit, to make sure that there is no pressure around the tube.
Then use a tube or someting round and hollow that is smaller in diameter than the fork's tube. Put this on the cap and use it as a chisel.
You may use a real hammer for this, because there is nothing You can damage inside. As soon as the cap gets loose, You will feel the spring going down. May be You will have to press the cap down and let it come up again a couple of times, until the cap pops finally out of the tube.
When You have let the air pressure out of the fork (!), and there are the original, weak, flat springs inside it, You don't have to fear much. The cap won't pop out for more than two inches.

Cheers,

Stefan

thanks guys
ended up spraying half can of Loctite freeze and release lubricant on to the cap
while using a bike (air) hand pump and to crease the pressure in the fork ( i had to change the seals too)
a couple of little taps on the cap with a socket and hammer . that worked
the cap shot across the garage  like a rocket taking out a set of works lights !
except now the air valve on the cap is trashed !!
oh well at least it came out !!

hi Stefan thanks for your concern
but don't worry
I used a bicycle  hand pump not an air compressor !!