15.8. Brake system

Fig. 15.70. Elements of anti-blocking system of brakes: 1 – hydraulic device; 2 – rotor of the sensor of frequency of rotation of a forward wheel; 3 – sensor of frequency of rotation of a forward wheel; 4 – diagnostic socket; 5 – sensor of frequency of rotation of a back wheel; 6 – rotor of the sensor of frequency of rotation of a back wheel; 7 – control unit; 8 – relay block


Part of cars of 1987 of release is equipped with disk brakes of back wheels, on a part of cars of 1988 of release the anti-blocking system of brakes (ABS) is in addition installed. The anti-blocking system installed since 1988 is intended for increase in stability of the car at sharp braking. It is reached by tracking of speed of rotation of each wheel and management of pressure in the brake system that prevents blocking of wheels. About existence of malfunction of system the control lamp of yellow color in a combination of devices signals. The anti-blocking system consists of the hydraulic device, the block of the relay, the control unit and sensors of frequency of rotation of wheels (fig. 15.70). The control unit is located in salon and is essentially system "brain", providing reception and processing of signals from sensors of frequency of rotation of wheels and developing teams of control of the relay of the block and hydraulic device. Because of complexity of the device it is expedient to carry out diagnostics and repair of system in service of car service. At work near wheels, the brake system or a suspension bracket of the car be careful not to damage sensors of frequency of rotation of wheels.

Back disk brakes
Design of brake shoes and cylinders, and also order of their check generally same, as well as for forward disk brakes. With back disk brakes we will apply the order of adjustment of wheel bearings and replacement of lubricant in naves described for drum brakes to cars of 1987 of release. On cars of 1988 and later years of release bearings of back wheels not folding, their adjustment is not required. As full dismantling of a support of back brakes requires the special tool, this work should be performed in the service center.
Replacement of brake shoes
Lift the car, fix on supports and remove a back wheel. Disconnect a cable of the parking brake from an arm and the lever of a support.

Fig. 15.73. Back disk brakes of cars of release of 1987: 1 – cable of the parking brake; 2 – brake hose; 3 – a support with the brake cylinder and brake shoes; 4 – fingers of brake shoes and plug; 5 – nave cap; 6 – nut; 7 – bearing; 8 – brake disk; 9 – brake support arm; 10 – protection cover of a back brake


In cars of 1987 of release twist the directing fingers and remove the brake cylinder (fig. 15.73). Remove brake shoes, having hooked them the screw-driver.

Fig. 15.71. Back disk brakes of cars of release of 1988: 1 – brake disk; 2 – clamping bracket; 3 – support bracket; 4 – V-shaped spring; 5 – brake shoes and noise-insulating laying; 6 – support bracket; 7 – cable of the parking brake; 8 – brake hose


In cars since 1988 of release turn off the top bolt of fastening and turn a support on an axis, having cast away it down to provide access to blocks (fig. 15.71). Remove a V-shaped spring, blocks, noise-insulating laying and the directing brackets.
The further replacement procedure corresponds provided in section 10 "Brake system".
Examine a brake disk and at strong damages replace it. On cars with ABS replace the sensor of frequency of rotation of a wheel located on a disk.
For all models kruglogubets turn clockwise pistons and press them into the cylinder. It is necessary for installation of new brake shoes which thickness is more worn-out.
Install in cars of 1987 of release in a support new blocks. Establish a support and tighten the directing fingers the required moment.
Since 1988 of release install in cars laying, blocks and clamping brackets, turn a support, having established it into place, and tighten a fastening bolt the required moment.
Repeat all operations for other back brake.

PREVENTION
Before a trip several times press a brake pedal to press blocks to a brake disk. Check the level of brake fluid and if necessary restore it. Be convinced of non-failure operation of work of brakes, before departure on the carriageway execute several control braking, moving at a low speed.