I just replaced the driver-side rear drum wheel cylinder and had the boot on the cylinder pinch against the inner hub, and feel like the piston inside the boot extended too far and caused it to pinch. I did not have the shoes installed when I pressed the brake pedal. Could this have happened because I did not have the shoes installed to put pressure on the cylinder?
My car has 187000 miles.
My car has a manual transmission.
The pistons that are within caliper bores, or drum brake wheel cylinders, are not intended to move any further than the limits set when the brakes are fully, 100% assembled, that is when the shoe and drum (in your case) are fully installed. If the piston is not "opposed" by the shoe pressing against the drum, yes the piston in the wheel cylinder will extend too far out. If it gets too far extended, of course brake line pressure (as you step on the pedal) could blow the piston completely out of the cylinder with the brake fluid along with it. If the piston in the wheel cylinder has come too far out, it is no big deal: just simply push it back in (open brake reservoir cap to relieve any air pressure) while being sure that the wheel cylinder boot is not pinched. After you are done be sure the cylinder is not leaking brake fluid in case the internal seal got twisted or damaged. If you need assistance, request wheel cylinder inspection/replacement and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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