What tool do you need to push the piston in caliber on rear brakes of a 2005 grand prix?
You'll need a C-clamp or a brake caliper piston compression tool. A C-clamp can work in a pinch, but a dedicated caliper piston compression tool is safer and designed to avoid damaging the piston or its seals. The tool will either push the piston straight in or rotate it as it compresses it, depending on the design of the tool and your specific caliper. Always consult your repair manual for the best method and to avoid damaging any brake components.