If the piston popped out of the caliper, then your only option here is to replace the caliper. It can't be put back together now.
December, 2, 2010 AT 4:37 PM
December, 2, 2010 AT 4:49 PM
Your best bet is to buy a rebuilt caliper. If they are still building the parking brake into the caliper, it is almost impossible to bleed the air out of the piston. That will leave you with a mushy brake pedal.
To reinstall that type of piston, you have to turn it to screw it in on the parking brake actuator rod. There is a special tool for that. If the parking brake is a separate drum brake inside the rotor like Chrysler uses, those calipers are treated just like any front caliper. There are three ways to put the piston back in. My favorite is to disconnect the hose, hold the piston over the rubber dust boot, and blow compressed air into the hole for the brake hose. When you force the piston down it will cause the boot to blow up around the piston, then push the piston in while releasing the compressed air nozzle. The second way is to remove the boot, place it around the piston, let it hang down, then use the piston as a handle to set the boot into place. Once the lip of the boot is in the groove on the caliper, pushing the piston down locks the boot in place. That works real well on Chryslers and with some difficulty on Fords. On Fords, the lip of the boot tends to want to pop out so you have to check very closely for that. It will not work on imports that use a wire ring to hold the boot to the caliper if the ring is hidden on the inside. It will work on those with the ring on the outside where you can see it. The disadvantage to this method is you have to peel out the boot which might be stuck in mud and rust. At that point you have to spend a lot of time cleaning it up to insure it will seal again. The third method is to buy a special pliers to grab the boot and spread it open as you drop the piston into place. Those pliers come in two sizes for different size calipers. The jaws are curved to approximate the diameter of the piston, and if you look at the end of the jaws, they are half-round to form a groove to hold the boot from sliding off. They are called "dust boot pliers".