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Watch out for the 2005 Ford Freestyle rear disc calipers!The Passenger Side Rear Caliper piston needs to be turned counter-clockwise to collapse it back into the caliper housing. All the piston compressing tools I have seen are made to turn the piston only clock-wise. So this tool only works for the Driver's side rear caliper because it's made to collapse and turn clock-wise! It's a 2 person job for the passenger side of the vehicle. You only use the adapter plate from the compression tool which fits into the slots on the face of the piston. While the first person holds that plate in place against the piston face, the secong person must position a 6" or 8" C-Clamp to fit up against the center bolt head at the back side of the caliper and then snug-up the c-clamp to hold the adapter plate in place. One person then uses channel lock pliers to grab the outside edges of the adapter plate to turn it counter-clockwise while the other person holds on to the caliper and c-clamp and tightens it after rotating the piston and adapter plate about 90 degrees or so. you have to keep doing this turning and tightening over and over until the piston is collapsed enought to be able to slide the whole caliper assembly over the pads on the rotor. It sounds like a real pain but it's the only way to collapse the piston into the caliper. Until the tool makers get smart and come up with a left-handed threaded adapter for their existing tools, this is the only way available to us right now.
Advance Auto sells a 3/8" ratchet adapter that allows you to turn the caliper piston either direction but just turning the piston will not retract it back into the caliper. I was not able to get the piston to retract with a ratchet but I was able to attach the adapter to my drill so I could firmly push on the caliper piston while I was spinning the piston with the drill. This caused the piston to retract on my 2008 Taurus-X. Toolbox 27 is correct, you must spin the piston clockwise on the driver's side and counter-clockwise on the passenger side.