The rear wheel brake mechanism is a drum brake with a two-piston wheel cylinder and automatic clearance adjustment between the shoes and the drum
The automatic clearance adjustment device is located in the wheel cylinder.
The main element of the device is a steel split thrust ring mounted on the piston with an axial clearance of 1.25-1.65 mm.
The thrust rings (two per cylinder) are inserted into the cylinder with an interference fit that provides a shear force along the cylinder surface of at least 350 N, which exceeds the force of the brake shoe tension springs.
When the brake linings wear out, the thrust rings shift under the action of the pistons by the amount of wear.
If the cylinder surface is damaged by mechanical impurities that have entered the brake fluid, or by corrosion (the presence of water in the brake fluid), the rings may "sour" in the cylinder and one or even both pistons will lose mobility.
In this case, the cylinders must be replace.
Replacing the pads
The rear wheel brake pads must be replaced only as a set - all four pads.
Replacing the pads of only one brake mechanism can cause the car to pull to the side when braking.
Using a spanner (preferably a high hex head) for 7, unscrew the two guide pins of the wheel.
Removing the brake drum.
If the drum cannot be removed, then, turning it evenly, strike the end of the drum with a hammer with a plastic tip (or a regular hammer through a wooden block).
Using a screwdriver, we remove the hook of the upper tension spring from the pad.
Removing the spring
We remove the upper pad stops from the slots of the cylinder pistons and take out the spacer bar.
Using a screwdriver, we remove the hook of the lower tension spring from the pad.
Removing the tension spring
Using a screwdriver, disengage the guide spring from the pad.
Removing the front pad.
Having disconnected the guide spring from the rear pad, lower the pad.
We remove the manual pad drive lever from the hole in the parking brake cable tip
Straighten the cotter pin and remove it from the hole in the handbrake lever pin.
Remove the washer from the pin.
Remove the lever and remove finger.
Install the manual brake pad drive lever on the new brake pad in the reverse order.
Install the new brake pads in the reverse order.
For ease of assembly of the guide spring with the brake pad, hook a wire or cord approximately 0.5 m long onto the spring hook.
Tightening the spring, insert its hook into the hole in the brake pad.
Then pull out the wire.
Before installing the drum, it is necessary to recess the pistons into the working cylinder.
To do this, press on the pads with two mounting blades, resting on the flange of the brake shield
After installing the drum, press the brake pedal several times to set the pistons to the working position. Adjust the parking brake.
Replacing the rear wheel brake cylinder
It is more convenient to perform the work on an inspection ditch or overpass. Remove the brake drum and the upper tension spring.
Remove the upper brake shoe stops from the cylinder piston slots.
To make it easier to unscrew the brake pipe nipple, you can unscrew the bleed nipple from the cylinder.
If the pipe does not unscrew and there is no spare pipe, you can first unscrew the two cylinder mounting bolts.
Pull out the cylinder with the pipe so that you can hold it with a wrench.
Then, by rotating the cylinder and holding the pipe with a wrench, you can dismantle the cylinder without damaging the pipe.
Using an 8 mm open-end wrench, unscrew the bleed nipple (the bleed nipple may also be for a 10 mm wrench).
Using a special 10 mm wrench, unscrew the brake pipe nipple.
Remove the pipe tip from the cylinder hole
Using a 10 mm open-end wrench or socket, loosen the two bolts securing the cylinder to the brake shield
Remove the cylinder
Install the new cylinder in the reverse order.
After assembling the brake mechanism (including installing the drum), bleed the hydraulic brake drive.
Replacing the rear wheel brake hose
Using a special 10 key, unscrew the brake pipe nipple, holding the lower end of the hose by the Allen key with a 15 key.
We remove the lower end of the hose from the hole in the rear suspension beam bracket.
Specialwith a 10 mm wrench, unscrew the brake pipe nipple, holding the upper end of the hose by the Allen key with a 15 mm wrench.
Remove the upper end of the hose from the body bracket hole and remove the hose
Install the hose in the reverse order. Bleed the brake system.
