So I ordered a new master cylinder for a 2002 Civic LX and had to order the push rod seal separately. When I went to replace the seal I realized I had been sent the wrong one. I replaced the cylinder with the old seal in place and am awaiting the correct seal now. Since removing the cylinder from the brake lines means I have to bleed the cylinder and the brakes, can I just unmount the cylinder from the firewall and move it forward just enough to replace the push rod seal? Or am I risking damaging the brake lines or something else?

By the way, the master cylinder look like the one below, so it's not the kind that goes into the booster.