Grind the mushroomed head off, use a cone shaped carbide burr in a die grinder and grind down into the countersink. Some thmes you can put the arm in a vise and with a big steel drift and a BFH you can knock the ball out, I use a hyd. press because I have one. Put in in the other side, now this shaft is tapered a bit so the first time I pressed one back in I used my vice and a socket to press it in, now I use the press. Weld the heck out of it, rosette weld the bottom overlapping big then run a couple of welds on the lip by the ball!!! <img src="/forums/images/graemlins/smile.gif" alt="" /> One thing I forgot, I preheat the arm before I weld it and once I am happy with the welds I stick it is a bucket of sand and let it cool completly. I have done six or seven and never had a failure. It has been a few years since I made the last one!!!