A piston insertion force gauge tool for measuring the insertion force of a piston into a bore of a brake caliper includes a housing assembly having an inner housing member at least partially disposed in an outer housing member, where the housing members are generally coaxial and selectively displaceable along the axis. First and second end members form the ends of the gauge tool. The inner housing member is received into the outer housing member at a second open end. A measuring device extends from the second end member through a first open end and to the first end member. The measuring device displaces the inner housing member with respect to the outer housing member to indicate the insertion force imparted on the piston.