The back brake mechanism of drum type has the device of automatic adjustment of a gap of brake shoes. At the same time the razzhimny level automatically changes the length and by that provides a constant gap between the brake drum and brake shoes. For this purpose between a forward block and a razzhimny level the wedge with the spring which is continuation of a razzhimny level is placed. The required gap is established after single pressing a brake pedal. If because of wear the course of a block increases, the wedge under the influence of a razzhimny level and a spring falls down. Thus length of a razzhimny level changes and the gap of brake shoes is automatically supported.

PREVENTION Surely you make replacement of all blocks on one axis even if the limit of their wear was reached by only one block.

You carry out removal and dismantling of the back brake mechanism in the following order:

to check thickness of back overlays of brake shoes of a drum brake. This check can be carried out, without removing brake drums;

remove the rubber stopper established over an entrance of a cable of the emergency brake on a brake board. By means of a portable lamp check thickness of overlays of brake shoes;

you will hang out and record a back part of the car on basic racks;

remove back wheels and switch off the parking brake;

the screw-driver uncover the central part of the brake drum;

take the fixing forelock and remove a blocking ring.

unscrew a nut and remove a persistent washer;

remove the external bearing;

turn the brake drum so that openings for bolts of fastening of a wheel settled down at an angle 45 ° from the vertical plane. Having inserted the screw-driver into a forward top opening for a bolt of fastening of a wheel, move a wedge up and release brake shoes;

remove the brake drum. If necessary use a universal stripper;

take a cuff and the internal bearing if he did not act together with a drum;

PREVENTION In order to avoid an exit of pistons from the working brake cylinder do not press a brake pedal at the removed brake drum.

clear the internal surfaces of the brake drum, check a condition of its internal surface for wear and damages. If it is necessary, replace a drum;

note a relative positioning of brake shoes and springs, for the subsequent correct installation;

having pressed flat-nose pliers on cups of springs, turn them on 90 ° and remove them together with springs. At turn of cups hold a pin from a reverse side of a brake board;

take brake shoes from the lower support. Remove brake shoes from the working brake cylinder and disconnect a cable of the emergency brake from blocks. To prevent loss of pistons from the working brake cylinder, fix them by a wire;

remove the lower coupling spring of brake shoes;

remove the top returnable spring and a spring of a tension of a wedge;

disconnect a clamping spring of a razzhimny level and remove a razzhimny level together with a wedge;

clear the brake drum, brake shoes and a brake board.

measure thickness of overlays of brake shoes.

PREVENTION Surely you make replacement of all blocks on one axis of the car even if the limit of wear was reached by one block. If blocks are repeatedly established, before removal they need to be marked.

You carry out assembly and installation of the back brake mechanism in the following order:

apply a small amount of lubricant on the contact surfaces of the lever of the parking brake and a razzhimny level;

Fig. 12.11. Installation of a front brake shoe on a razzhimny level

clamp a razzhimny level in a vice, establish a tension spring on a razzhimny level and a front brake shoe and put on a block a razzhimny level ( fig. 12.11 );

establish a wedge between a brake shoe and a brake board, at the same time the nose of a wedge has to be directed to a board;

insert a brake shoe with the lever of the parking brake into a razzhimny level and establish the top returnable spring;

remove the wire holding pistons from loss from working brake cylinders;

connect a cable of the parking brake to the lever of the parking brake;

establish the top part of brake shoes in grooves on pistons of the working brake cylinder;

establish the lower returnable spring on brake shoes, then establish the lower part of blocks on a support of blocks;

establish a wedge tension spring;

establish the holding pins, press springs and cups. Press on a cup, holding pins from the back party of a brake board, and turn a cup on 90 °, before its accurate fixing;

move a wedge up to create the maximum gap of brake shoes;

insert the internal bearing together with the lubricant applied on it into the brake drum and establish a cuff;

install the brake drum;

apply lubricant on the external bearing and install it on a pin;

establish a persistent washer and screw a nut;

establish a blocking ring and the new fixing forelock;

establish a cover on the central part of the brake drum;

establish wheels and lower the car;

press once a brake pedal to establish the required gap of brake shoes;

similarly replace the brake drum and back brake shoes on the second wheel.