I'm assuming that your asking about BENDIX 4 piston caliper disc brakes on a B body car?
If so, be prepared as rebuild kits, and especially caliper pistons, are pretty much on the unobtanium list to find, and get, in this modern day and age.
And the prices that you would have to pay are hugh $$$$$$$$$ these days.
By chance if your asking about A body, Kelsey Hayes, 4 piston calipers, i rebuild them.
Jim V.
hemi71x