For automatic clearance adjustment, an adjusting lever with a tension spring is installed near the parking brake lever, with which you can extend the adjusting mechanism plunger. Brake linings belong to the category of materials for which an operating permit is required and they are included in the General Operational Permit Register (ABE).
In addition, they are selected by the manufacturer for certain car models. Therefore, it is recommended to use only pads offered by the manufacturer or approved by the Federal Automobile Administration. These pads have a number assigned to them by the Federal Automobile Administration.
Attention! If the brake pads are to be reinstalled for later use, they should be marked before removal. Swapping pads from the right wheel to the left and vice versa is not allowed. Such a rearrangement can lead to uneven braking of the wheels. It is obligatory to install only original brake pads or pads recommended by the vehicle manufacturer. Be sure to change all front brake pads, even if only one of them has reached the wear limit.
Attention! It is recommended to remove the brake mechanism from only one side so that, if necessary, you can check on the other side.
Removing
Attention! Before dismantling the individual elements of the drum brake mechanism, remember or mark their mounting position. If necessary, check the mechanism on the other side.
1. Mark with paint the position of the rear wheels on the hubs. This will allow the assembly to set the balanced wheel in its original position.
2. Loosen the wheel bolts. The vehicle must be on wheels during this operation.
3. Install the car on the goats and, having unscrewed the wheel bolts, remove the rear wheels.
Attention! Jacking up a vehicle or placing it on jack stands is dangerous. Therefore, it is recommended that you familiarize yourself with the safety precautions outlined in chapter «car jacking».
4. Release the parking brake.
5. Unscrew the fixing bolt 1 and remove the brake drum 2 from the hub (see illustration).
Attention! A tight-fitting brake drum can be knocked off the hub with light blows from a plastic hammer and then removed by gently prying it out with a screwdriver.
If the brake drum does not give in and cannot be removed from the hub, proceed as follows:
6. Remove the rubber plug on the back of the shoe support shield and press the brake shoe drive lever with a screwdriver 1 towards the middle of the drum, and then remove the drum (see illustration).
7. Disconnect return spring 1 using HAZET 797 pliers (see illustration).
8. Disconnect the expansion bar 2 from the brake shoe lever and disconnect the coupling spring 3 from it (see illustration 10.7).
9. Spread the brake pads at the top and remove the adjusting mechanism with the expansion bar 4 (see illustration).
10. Press with a screwdriver 2 on the clamp 1 of the pin head, which secures the brake shoe, and remove it from the pin (see illustration).
At the same time, on the other side, support the pin with your hand. After releasing the pin head, remove the clip from the pin and remove the pin. To facilitate this work, you can use HAZET 2796-1 spring pliers.
11. Remove the pin on the second block in the same way.
12. Disconnect the bottom coupling spring of pads.
13. Remove brake shoes, having disconnected a cable of a drive of a manual brake from a back block.
14. Wrap the brake cylinder around the ends with a fastening belt or install clips so that the piston does not come out of the brake cylinder. When removing the pads, it is forbidden to pull out the piston, because. otherwise air gets into the brake system and it will have to be pumped.
Attention! Do not damage the cuffs of the wheel brake cylinder.
Attention! With the brake pads removed, do not press the brake pedal. Otherwise, the piston will be squeezed out of the brake cylinder. If the piston is still out of the cylinder, then remove the caliper and deliver it to a specialized workshop for repair.
Examination
Be sure to replace all four brake pads with new ones. The pads to be installed must be from the same manufacturer. Use a vacuum cleaner to remove dust from the brake drum and caliper and wipe them with alcohol.
Attention! Brake dust can be harmful to health. Use a respirator to avoid dust inhalation. With the brake pads removed, do not press the brake pedal. Otherwise, the piston will be squeezed out of the brake cylinder.
15. Take away by hand, or prying with a blunt object, anthers 1 and 2 of the wheel brake cylinder (see illustration).
Attention! In this case, the piston must not be pulled out of the brake cylinder.
If it is dry under the anther, then install it in its original place. If brake fluid leaks from the cylinder, the wheel brake cylinder must be replaced.
16. Replace damaged boots.
17. Check the surface of the brake drum to the touch for grooves and grooves. Damaged drums must be replaced or turned. Measure the inside diameter of the drums. The wear on both drums should be the same. When the wear limit is reached, both brake drums of the rear wheels should be replaced with new ones. For specifications and wear parameters, see «Specifications».
18. Sand down with sandpaper (grit 150) slight bumps and traces of rust on the surface of the drums.
Installation
19. Clean and lubricate the surface of the brake pad support plate before installing with a thin layer of high temperature paste, such as «LUBRITHERM G 2000».
Attention! The paste must never come into contact with the friction surfaces of the brake linings or the brake disc. In case of contact, immediately remove the paste, and if necessary wipe the surfaces with alcohol.
20. Lubricate with a thin layer of protective paste the threads and contact surfaces of the axis of the adjusting gear, as well as the axis of the lever to which the expansion bar is attached.
21. Completely unscrew the axis of the adjusting gear 1 from the expansion plate 2 and check the thread for ease of movement of the axis. Make sure that the bimetal washer 3 fits exactly into the groove 4 of the expansion bar (see illustration).
22. Fasten the handbrake cable to the rear block and make sure it is installed correctly.
23. Fix the lever 1 of the fastening of the expansion bar to the lower pin of the front brake shoe (see illustration).
24. Fix the return spring 2 on the expander bar lever and on the brake shoe (see illustration 10.23).
25. Fix on both pads the lower coupling spring 3 (see illustration 10.23). In this case, one hook of the spring is wound from the back side through the hole on the rear brake shoe clamp.
26. Install the brake shoes on the support plate and make sure they are properly seated on the lower rail.
27. Fasten the brake shoes on the support plate by inserting the retaining pins 4 into the holes on the support plate from the back side, and insert their holes on the brake shoes. Slide the clips 5 onto the retaining pins of the pads from below with a screwdriver so that they go under the pin heads. In this case, the pins should be supported and pressed by hand on the back side of the brake pad support shield (see illustration 10.23).
28. Remove the belt or spring from the wheel cylinder that was installed to prevent the piston from coming out.
29. Spread the brake pads at the top and install an expansion bar between them, securing the axis of the adjusting gear on the front shoe. In this case, the flat side of the bimetallic washer faces the support shield of the brake pads, and the protrusion on it (see arrow in illustration 10.9) went into the groove on the expansion bar.
Attention! If necessary, compare the setting of the adjuster with the position of the adjuster on the other wheel.
30. Attach the upper return spring first to the rear brake shoe, and then hook the elongated hook of the spring with special pliers or suitable needle nose pliers to the front shoe.
Attention! Compare this setting with the position on the other wheel.
Attention! Before installing the brake drum, check the correct installation of the brake shoes, springs and adjusting mechanism by comparing with another wheel.
31. Install the brake drum on the hub so that the holes for the mounting bolts match the holes on the flange of the cross beam.
32. Fix the brake drum with new self-locking bolts and tighten them to 10 Nm.
33. Lubricate the shoulder of the rear wheel hub with a thin layer of grease.
34. Adjust the parking brake, see relevant chapter.
Attention! On vehicles with drum brakes, adjust the brake shoe adjuster so that the brake shoes are fully seated on the brake drum. To do this, start the engine and depress the brake pedal several times to ensure sufficient braking force.
35. Establish wheels according to the marks put at removal. Before doing this, lubricate the centering seat of the wheel disc on the hub with a thin layer of grease. Do not grease wheel bolts. Replace rusted bolts with new ones.
36. Screw in bolts of fastening of wheels and lower the car on wheels.
37. Tighten the bolts in a cross pattern to 110 Nm.
38. Carefully run in new brake pads. To do this, slow down several times, bringing the speed from about 80 km / h to 40 km / h and lightly pressing the brake pedal. Let the brakes cool down in between. During the first 200 km of driving with new brake pads, avoid unnecessary braking until the car comes to a complete stop.
Attention! Brake linings must not be disposed of with normal waste, as the dust that forms on them is hazardous to health. They need to be disposed of only at special points.
Attention! Make sure that:
- A) brake hoses are securely connected;
- b) brake hoses are fixed in holders;
- V) fittings for bleeding the brake actuator are wrapped;
- G) there is enough brake fluid in the expansion tank.
39. Perform a brake leak test by starting the engine. Depress the brake pedal with a force of 200-300 N (20-30 kg) and hold it for about 10 seconds. The pressure in the system and, accordingly, the resistance of the brake pedal, should not decrease. Check all connections for tightness.