Caliper piston removal options

[1970 cuda Joe]

That caliper has the seal in a groove of the housing & the piston moves across it. The nwe seal will need to have a good seat in the housing. The piston will most likely need to be replaced. I'm really surprised the piston hasn't come out yet....Joe

[Floyd]

It sounds like you're enjoying the challenge but if you decide to seek professional help I recommend sending it to Brake and Equipment Warehouse in MN.  They do great work and are very in tune with collector car restoration work.  They rebuilt my calipers, master cylinder and proportioning valve.

https://brakeandequipment.com/

[mtull]

Thank you @Floyd.  I talked to Brad a few months ago.  I was surprised he was available and was kind enough to walk me through best practices for packaging and shipping parts as well as many other details.  The eventual goal is to have Brake and Equipment Warehouse do everything but for the short term I just need to get the car out of the garage in order to gut and remodel the space. 

[mtull]

It sounds like you're enjoying the challenge but if you decide to seek professional help I recommend sending it to Brake and Equipment Warehouse in MN

I decided to give removing the caliper piston one more try.  Previous failed attempts included soaking the assembly in a home made de-rusting solution for a few days, penetrating oil, heating with a torch and finally compressed air. 

The entire time I had @Floyd quote in my ear.  I decided the final attempt (good or bad) would be to tap the piston and pull it out using a long bolt and nut.  I was a bit nervous to say the least, worried I would damage the cast iron or that new pistons and seals wouldn't fit correctly.

You get an idea in the second picture how much pulling force was used by how much the 3/4" plywood was deformed.  The plywood scrap gave way so I switched over to an old piece of leaf spring and a new bolt/nut.  The piston finally popped out.  Maybe it's just me trying to validate my last ditch approach but I don't think 160 psi of compressed air was ever going to move that piston. 

Ironically, the nicest, least pitted caliper proved to be the hardest piston to remove.   

[mtull]

Calipers soaked in de-rusting solution and scrubbed clean. It took a bit of work to get the crud cleaned out of the grooves and all the surfaces cleaned up.

[mtull]

I bought new pistons, seals and a small bottle of hydraulic brake assembly lube.  The pistons move when 120 psi introduced, luckily no leaks.  I did notice the new pistons are .004 smaller than the originals however the new seals are a bit thicker.  Did the old seals shrink? 

The real test comes next when I put them on the car.  Fingers crossed no leaks.

[Katfish]

Well done! I would have given up long ago

[mtull]

Well done! I would have given up long ago

Thank you.  There's something to be said for having the professionals do the work.  I can't declare victory yet.  If they leak, then we'll all know I should have given up and listened to @Floyd