so im buying calipers and brackets from this guy parting out a car cause my rears r seized and i need them working to pass safety.

what im wondering is how can i test or tell they r in working order and will work when he brings them to me ?

any way ican test them b4 i buy em ?

 

You can use a pair of needle nose pliers to turn the piston. It should turn freely. Clockwise to push it in, Counter-clockwise to turn it out. However that only checks the piston. No way to tell if it has leaks without installing it and pressuring it up.

 

If the tops are wet with brake fluid where the parking-brake pivot is, skip them; they will require a complete rebuild, which is NOT worth the money or the time. The pivot should turn smoothly throughout its range with no roughness or hitches.

Screw the piston out with a very large screwdriver or a set of needle-nose pliers (the screwdriver will work better) so the boot is fully extended, but not so far that it pulls out of its groove in the piston. Spray brake-cleaner on the boot to get rid of particles, then pull the boot back from the piston. Inspect the piston for corrosion from the groove back. If there is any corrosion, even one black dot, don't buy the calipers unless you want to rebuild them (however, rebuilding is not difficult if you approach it correctly).

If the piston screws in with great difficulty, you will also find corrosion on the piston. If the piston screws in with roughness while turning, then the caliper is an aftermarket reman, and is worth less than genuine OE.

 

so i should just go buy new ones eh??

the fronts r fine for now, just the one in the back is seized, but their all atleast ten + years old, so ima replace both backs for now, since i have new pads already ill just throw them on too so i can pass safety.

 

Aftermarket remans should be available at NAPA and other places, and will be a much better bet than used ones of unknown provenance. Phone around.

Or you can rebuild your old calipers. They stick because the piston gets corroded. Replace the piston (and the square-cut seal and the dust-boot), and you're good to go. OE pistons are about $80 each, but you may be able to find cheaper aftermarket ones. The problem with aftermarket pistons is that they often have less interior machining done to them, which makes it tougher to bleed the air out of the caliper.