21.7. Replacement of brake shoes of a forward brake of HP-2


Fig. 15-8. Forward brake of HP-2: 1 – bolt, 25 N · m; 2 – arm; 3 – bolt, 200 N · m; 4 – brake hose, 15 N · m; 5 – a brake support with the mass shock-absorber; 6 – bolts of Torx, 25 N · m; 7 – socket; 8 – brake tube; 9 – holder; 10 – the brake shoes equipped with the mass shock-absorber and the spring eliminating high-frequency fluctuations (squeal); 11 – brake disk


The device of a forward brake is shown in fig. 15-8.

Removal
Surely replace all blocks on one axis of the car even if only one block is worn-out. Brake shoes are equipped with the wear indicator. If thickness of brake shoes becomes less than 3 mm, in a combination of devices the control lamp lights up.
If old brake shoes are established again, before removal they need to be marked.
Weaken bolts of fastening of a forward wheel, then lift a forward part of the car and fix on supports. Unscrew bolts of fastening and remove a wheel.
Fix a brake disk, having screwed in one bolt of fastening of a wheel.

Fig. 15-9. Arrangement of bolts of fastening of external brake shoes and brake disk



Unscrew two bolts of fastening of external brake shoes (fig. 15-9).

Fig. 15-10. Use of the screw-driver for cave-in of pistons in a support



By means of the edge of the screw-driver inserted between a support and an external brake shoe press pistons into a support, at the same time move a support outside (fig. 15-10). At cave-in of the piston brake fluid is forced out from the brake cylinder in a broad tank therefore constantly control liquid level in a tank, and if necessary pump out a small amount from a tank.
Remove external brake shoes from a support.
Disconnect the electric socket of the sensor of wear of a brake shoe and take a wire from an arm in a support. For this purpose an edge of the screw-driver squeeze out the rubber plug with a wire from an arm and turn it on 90 ° at first in one, then in other party.

Fig. 15-11. Use of the screw-driver for movement of a support to the car



Move with the screw-driver edge inserted between a support and an internal brake shoe a support of a forward brake to the car (fig. 15-11).
Remove internal brake shoes from a support.

Installation
Do not press a brake pedal at the removed brake shoes.
Purify dust and dirt from a support, and from edge of a brake disk – a rust. If blocks are suitable for further operation, clear them a wire brush and rags.
Check a brake disk for existence of cracks, especially around openings under bolts of fastening of a wheel, and also and if necessary replace it with existence of wear or mechanical damages.
Measure thickness of a brake disk.
Establish the top internal brake shoe with the wear sensor in a support of a forward brake. Fix a brake shoe in the support piston. Fix a wear sensor wire in a support arm.
Move a support of a forward brake from the car as far as it is possible. Remove a protective film from a sticky layer of external brake shoes and establish them on a support, at the same time the brake shoe has to be recorded by a spring.
On a brake shoe the arrow is put. It has to coincide with the direction of rotation of a disk at the movement of the car forward. Otherwise during the work brake shoes will be published by extraneous noise.
Fix a floating support by new bolts, having tightened their moment 25 N m.
Unscrew a bolt of fastening of a wheel, the fixing brake disk. Establish a wheel and lower the car on the earth. Having cleared ridge heads of a bolt, tighten bolts of fastening of a wheel the moment of 120 N · m.
Similarly replace brake shoes on the second forward wheel.
Several times press a brake pedal that brake shoes nestled on a brake disk.
Check the level of brake fluid in a tank, if necessary add.
After installation of new brake shoes avoid sharp braking the first 200 km of a run of the car.