i've received replacement rotors, bearings and seal to address the 50 year old Kelsey Hayes worn rotors. Upon caliper removal and pad removal, i noticed the caliper pistons were stuck. the inboard pistons would not expand. i noticed some rust around the rubber boots, but boots not torn. after further reading and some youtube video searching it looks like my old calipers need some upgrading. is it worth the effort and trouble to rebuild 50 year old calipers with new piston, seals, crossover tube and bore hone? i was able to expand all pistons finally using some blocks of wood to hold the pistons and press the brake pedal a few times. i havent disconnected the brake hose yet or removed a piston to look for internal corrosion. input appreciated, thanks.
In this case, because the caliper design is a bit more precise than the later single-piston units, I'm of the opinion you should go with rebuilds, BUT, if you plan on a full concours restoration, keep the old ones for a pro rebuild eventually, and pay the core price. If you're not, just buy and swap. More money, but a LOT LESS hassle. You should also replace the hoses and copper washers.
If you do decide to rebuild them it will be wise to get one of these https://www.amazon.com/OTC-4799-Piston-Removal-Locking/dp/B009S4SZ3S there are other types out there. Never used this type most of the ones I did were single pistons and pistons . Removed with air and a block of wood to limit travel. I have done 4 piston caliper F250 front calipers and it was a real problem getting the pistons out after splitting the caliper with out the tool
That is a pretty cool tool, never seen one before. I have always used compressed air to remove pistons and a big old C clamp and piece of wood to prevent the piston from shooting across the room if the pressure has to be raised higher than about 30psi.
