[Aussie Mike]

You can get a special slide hammer that has a collet chuck on the end to grip the dowels. It's probably a bit pricey though.

You've got a tig welder. If they are hollow dowels, tack weld a nut to the end of the dowel and run a bolt in to push it out. Like a harmonic balancer puller works. You won't be able to re use the dowels but you are replacing them anyway. If they are solid dowels drill a hole in it and run a tap through and do the same trick.

Cheers