Brake rear: 1 - front brake shoe; 2 - shield of the brake mechanism; 3 - an earring of the gap adjustment mechanism; 4 - upper coupling spring; 5 - gap regulator; b - working cylinder; 7 - spacer bar; 8 - rear brake shoe; 9 - support post; 10 - retraction spring of the spacer bar; 11 - expanding lever of the parking brake drive; 12 - parking brake cable; 13 - lower coupling spring
Attention! Replacement of brake pads is carried out only with a set of four pads per rear axle in order to avoid uneven braking of the wheels and the possibility of skidding the car.
Figure 7.16. Drum brake parts: 1 - upper coupling spring; 2 - clamping device; 3 - clamping brake shoe; 4 - lower coupling spring; 5 - base plate; 6 - squeezing brake shoe; 7 – a return spring of an adjusting rack; 8 - automatic gap adjustment device
Removing
- remove the brake drum as described above;
- carefully remove dirt and dust from the drum, pads and brake shield with parts installed on it;
- use pliers to press the cap of the clamping device «Push», turn it 90°and remove the cap, spring and post. Do the same on the other block;
Figure 7.17. Removing the shoe from the base plate
- using pliers, disconnect the lower ends of the pads one by one from the base plate (Figure 7.17) and remove the lower spring from the brake pads;
- remove the upper stops of the pads from the brake cylinder, being careful not to damage the rubber anthers;
- disconnect the parking brake cable from the working lever;
- remove both pads from the brake shield together with the springs and the spacer;
Attention! Before installation of blocks and drums do not press a brake pedal.
- tighten the pistons of the brake cylinder with a strong rubber band;
- install the removed assembly on the workbench, mark and remember the location of the mating parts;
- release the locking lug of the parking brake release lever from the clamping block;
- disconnect the adjusting strut bolt spring from the clamping block;
- disconnect the upper return spring;
- disconnect the compression shoe and return spring from the squeeze shoe assembly with the adjusting post;
- unhook the adjusting strut return spring from the release shoe and separate them;
- measure the thickness of each pad in several places and, comparing the results of measurements with the minimum thickness of the pad, decide whether to replace or continue to use the pad. Lubrication of the friction surface of the pad clearly indicates the need to replace it. At the same time, the cause of the oiling should be identified and eliminated.
Replacement order:
- remove the parking brake operating lever from the old release shoe and install it on the new shoe, securing it with a new retainer that is attached to the set of shoes;
- remove the bolt from the adjusting post and inspect the assembly for wear and damage, paying special attention to the adjusting bolt and wing. Replace defective parts;
Attention! When replacing pads, all coupling springs must also be replaced, regardless of their condition.
Attention! Adjusting racks of the right and left wheels are not interchangeable. The right strut adjusting bolt is right hand threaded and painted. The left bolt has a left-hand thread and a groove on the head, respectively. The right adjustment column is marked with the letter «D», left - letter «G».
- make sure that the parts are installed correctly, apply molybdenum grease to the threaded part of the adjusting bolt;
- screw the lamb close to the head of the adjusting bolt and install the bolt in the rack;
- attach the return spring with the short side to the release block. Hook the adjusting post on the other end of the spring and insert the post into place in the slot in the release shoe;
- hook the top return spring onto the release shoe. At the other end of the spring, hook the clamping block and, lowering it down, insert the head of the adjusting rack bolt into the cutout of the block;
- put the bolt spring into the slot of the pressure block;
- release the cylinder pistons from the rubber band;
- carefully remove the rubber boots from the brake cylinder pistons. Make sure that there is no fluid leakage and that both pistons move easily. In the absence of defects, install the anthers in place;
- Apply high temperature brake grease to all contact surfaces of the pads and brake shield. Observe the measure when applying lubricant, otherwise it may get on the friction surfaces of the pads;
Figure 7.15. Stop lug on parking brake release lever (arrow) should rest against the edge of the block
- make sure that the stop lug on the parking brake release lever rests against the rib of the release shoe (see Figure 7.15);
- install the sub-assembled block assembly on the brake shield. Insert the top ends of the pads into the slots of the brake cylinder pistons. Attach the tip of the parking brake to the working lever;
- install the lower coupling spring on both pads and, overpowering the spring, install the pads with their lower ends into the base plate;
- moving the pads along the brake shield, center them and install clamping devices on each;
- with the lamb of the adjusting mechanism, adjust the position of the shoes so that they can be put on the brake drum with a slight effort;
- follow the same procedure with the brake drum on the other side of the car;
- do not tighten the hub nuts yet;
- adjust the position of the pads by depressing the brake pedal repeatedly (about 20 times);
- ask an assistant to make sure that when you release the brake pedal in the drums, clicks are heard from the operation of the gap adjustment mechanism;
- remove the brake drums;
- make sure that the thrust lugs of both release levers of the parking brake rest against the edge of the release block, the parking brake cables move freely in the sheath;
- with a helper, adjust the parking brake cable so that the levers on each brake plate begin to move between the first and second clicks of the ratchet mechanism of the parking brake lever in the car, i.e. so that at the first click the persistent protrusion of the expanding lever still rests against the edge of the block, but at the second click it already moves away from it;
- in this position, while holding the cable adjusting nut, tighten the locknut securely;
- install the brake drums as indicated in the relevant subsection.