I resealed/rebuilt a 4500 not ling ago that yses the same system. I can't remember how I got the tapered pin out, but it was something similar, just minus the air hammer. The leaks are the easy part. Fixing the play in the linkage could get expensive. I has one part machined to replace a worn guide pin. Works great now.
I’m lucky to not have much play, fortunately. Pin holding the rod end of the cylinder was in good shape- definitely had some slight wear, but hardly any material loss on the pin itself.
Tip to anybody doing this on any 4400/5000 with the 735 loader- jack up the loader subframe, take off the pump cover, via the 4 bolts holding the subframe horns. Remove the pressure side line on the pump, and 2 bolts holding the pump plate to the bolster. Remove 4 bolts holding the shaft adapter to the crank pulley. Push the adapter forward with a pry bar as far as you can on the splines. Put a pair of vice grips on the shaft, and hit them from the side, sliding the shaft back towards the crank pulley. Tilt the pump down so the shaft faces up towards the sky. Slide the pump out.
I also recommend putting a bolt or two back in tying the horns to the frame just for safety. That loader is heavy and cumbersome and I think an engine hoist is nearly essential to do this safely.
Loosened the castle nut holding the tapered pin tonight. I’ve been spraying PB blaster on that all week- I’m looking for all the advantage I can get- sources tell me it’s a real booger to get outta there!
The good news (less good for my wallet) is that now is a great time to replace the water pump, fan belt, steering lines, and power steering filter. (Thermostat would be a good idea too, but I changed that when I did the coolant 2 winters ago)
My local mom n pop hydraulic shop made me a flex line with crimp fittings to replace the existing rubber section of the pressure line. Plan is to cut the tubing with a hacksaw next to the fittings on the old flex line and splice in the new one.
This also brings the advantage of having a replaceable assembly should trouble arise down the road.