I recently replaced all 4 front brake cylinders and then bled the brakes. I filled it with brake fluid and bled them while the brake drum was not installed. I noticed while pumping the brakes, two of the cylinders' seals popped off and leaked the brake fluid. My concern is once I reinstall the drums that this seal will come off again and pour out the fluid. Are you not supposed to bleed the brakes without the drum installed?