In order to change and install the wheel cylinder, initially raise and support the rear end using jackstands then take off the brake drum and shoes. Unscrew and unscrew the brake line(s) in the wheel cylinder, and then screw out the backing plate attaching nuts at the back, then install in the same way. In the case of overhaul, kits can be supplied, but frequent use is made of a new or refurbished component. In case of an overhaul, it is important not to put contaminants in the system by fitting clean, fresh, and quality brake fluid. In case dirty fluid was used drain and flush the system, replace all the rubber parts and fill and bleed again. Start by taking off the wheel cylinder and putting it on a working bench. Pop off the old rubber boot, and clean out the rubber pistons, then scrape out the remaining parts of the inside, seals, spring-assembly, etc., with compressed air where possible. Wipe the cylinder and metal components with denatured alcohol or clean brake fluid, but not mineral based solvents. Air dry parts or blow them off with compressed air, checking the piston to make sure it is not scratched, and changing it where needed. Clean the cylinder bore and seals with clean brake fluid, install the spring assembly, insert the inner seals and pistons and new lubricant-free boots, then install lastly the wheel cylinder.