Been doing mechanic work for 45 years. Everything from a simple oil change to pulling engine, tearing down, sending to automotive machine shop, rebuilding And giving owner a warranty IF they agree to let me put a rev-limiter on it so I can see and show the owner if the engine has been abused by excessive RPM’s during said warranty. for pushing a brake caliper piston(s) back in I use a c-clamp and one of the worn out brake pads. Easy and it pushes the piston back in evenly