Disassembly Procedure

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

WARNING:

Do not place fingers in front of the caliper piston (s) in an attempt to catch or protect it when applying compressed air. The piston (s) can fly out with force and could result in serious bodily injury.

Courtesy of GENERAL MOTORS COMPANY

CAUTION:
Use clean cloths to pad interior of caliper housing during piston removal. Use just enough air to ease the pistons out of the bores. If the pistons are blown out, even with the padding provided, it may be damaged.

Remove the rear brake cylinder piston (1) from the caliper bore by directing low pressure compressed air into the caliper bore through the brake hose inlet port.
Using a plastic tool, remove and DISCARD the rear brake caliper piston boot (2).
Using a plastic tool, remove and DISCARD the rear brake caliper piston seal (3).
Courtesy of GENERAL MOTORS COMPANY

Rear Brake Bleeder Valve Cap (1) - Remove
Rear Brake Bleeder Valve (2) - Remove

NOTE:

Do not remove park brake piston apply spindle, washer or washer bearing.

Clean the brake caliper piston bore with denatured alcohol, or equivalent.
Inspect the caliper bore for cracks, scoring, pitting and corrosion.
If cracks, scoring, pitting or corrosion exists, replace the brake caliper.