Removal of D4 thermostat

Take two 3/8 capscrews and grind the heads to make the legs of a puller. You want them to grab under the retainer on one edge and jam against the thermostat on the other side when stood up straight. Then drop a spool of pipe bigger than the retainer over the two bolts and finally drill a piece of flatiron for them to poke up through and put nuts on. Tighten evenly and it pops the retainer out. Best results are with a short spool of pipe, short bolts and a fairly thick piece of steel on top, so there is less tendency for them to move toward the center and slip off.

Take two 3/8 capscrews and grind the heads to make the legs of a puller. You want them to grab under the retainer on one edge and jam against the thermostat on the other side when stood up straight. Then drop a spool of pipe bigger than the retainer over the two bolts and finally drill a piece of flatiron for them to poke up through and put nuts on. Tighten evenly and it pops the retainer out. Best results are with a short spool of pipe, short bolts and a fairly thick piece of steel on top, so there is less tendency for them to move toward the center and slip off.

I Think we need a photo of your themostat retainer puller.

Thanks for the ideas. I was thinking to drill & tap a couple of holes in the retainer and use a bridge puller setup like that. There is a slot on each side of it
but they are pretty skinny to get a hook under. I guess Cat still sells them but if I can I would like to preserve the parts if possible.

Gary