Removing
Place chocks under the front wheels, then raise the front of the vehicle and secure it with stands under the axle. Remove the drive wheel.
Remove the brake drum as outlined in the previous section.
Using pliers, remove the hook of the upper return spring from the brake shoes, noting their location, then spread the upper ends of the shoes apart so that they are free from the brake cylinder.
Working under the hood, remove the cap from the brake fluid reservoir and secure a piece of polyethylene to the filler neck with a rubber band, or by refitting the cap. This will reduce fluid loss during further operations.
Remove the brake fluid line nut from the wheel brake cylinder and disconnect the line itself. Try not to stretch the tube. Possible fluid leakage, so plug both ends to prevent contamination and further fluid leakage (pic. 9.16).
Unscrew the two fixing bolts from the rear side of the brake pad platter and pull out the wheel brake cylinder.
Repair
Brush off dirt and dust from the wheel cylinder, being careful not to inhale the dust.
Remove the rubber dust seals from the cylinder body.
Pistons usually exit under spring pressure; if necessary, lightly tap the end of the cylinder body through a piece of wood, or use low pressure air, such as from a foot pump, to the hole in the back of the cylinder body.
Inspect piston surfaces and cylinder bores for scratches or obvious metal-to-metal contact. If this is evident, replace the entire brake cylinder assembly.
If the pistons and bores in the cylinder are in good condition, remove the seals and install the necessary new parts.
Lubricate the piston seals with clean brake fluid and insert them by hand into the cylinder bore with the spring in between.
Dip the pistons in clean brake fluid and insert them into the cylinder bore.
Install dust seals and make sure the pistons move freely.
Installation
Place the wheel brake cylinder on the platter and tighten the bolts.
Connect the brake fluid line to the cylinder and tighten the nut.
Move the brake pads to the pistons, then install the upper return spring.
Install the brake drum and tighten the screw. If necessary, unscrew the fine adjustment knob until it sits on the shoes.
Remove the polyethylene from the neck of the brake fluid reservoir and bleed the appropriate circuit of the brake system, as indicated in the second section of this chapter.
Adjust the brakes by applying the foot brake. A clicking sound indicates the operation of the automatic regulator in the drum. When the clicking stops, the adjustment is complete.
Install the road wheel and lower the vehicle to the ground.
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