21.6. Replacement of brake shoes of a forward brake of FN-3
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Fig. 15-4. Forward brake of FN-3: 1 – brake tube; 2 – protective cap; 3 – the directing finger, 25 N · m; 4 – brake hose, 15 N · m; 5 – support; 6 – bolt, 120 N · m; 7 – holder of a support (guide of brake shoes; 8 – brake shoes; 9 – spring; 10 – brake disk; 11 – arm; 12 bolt, 10 N · m
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The device of a forward brake is shown in fig. 15-4.
Removal
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.
Surely replace all blocks on one axis of the car even if only one block is worn-out. If brake shoes are repeatedly established, before removal they need to be marked.
Remove protective caps from the internal ends of the directing bolts.
Using a screw-driver edge as the lever, from the outer side of a support remove the fixing spring (fig. 15-5).
Lift a support with an internal block and a soft wire tie up it to a forward rack. The support should not hang on a brake hose. The brake hose should not stretch or be overwound.
Remove an internal block from the piston of a support and an external block from the holder of a support.
Installation
Do not press a brake pedal at the removed brake shoes.
When replacing brake shoes do not unscrew a brake tube.
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 both disks with existence of wear or mechanical damages.
Measure thickness of a brake disk.
If establish new brake shoes, press the piston into a support, using special adaptation. It is possible to press the piston into a support also a wooden core or the handle of the hammer. At the same time you watch that the piston did not warp also the surfaces of the piston and a boot were not damaged. At a piston vdviganiye brake fluid is forced out from the brake cylinder in a broad tank therefore constantly watch liquid level in a tank, and if necessary pump out from a tank it a little.
Establish an internal block on a support, at the same time the spring bracket has to enter dredging of the piston. On an internal brake shoe with a spring the arrow is put. It has to coincide with the direction of rotation of a disk at advance. Otherwise during the work the brake shoe will publish extraneous noise.
External brake shoes fasten a sticky layer on the support plate.
Remove a protective film from a sticky layer of an external brake shoe and establish it on the holder of a support (fig. 15-7).
Establish a support with an internal block on the holder of a support. Screw in the directing fingers of a support and tighten their moment 25 N · m.
Establish protective caps on the directing support fingers.
Establish the fixing spring on a support, having arranged the ends of a spring in support openings.
Similarly replace brake shoes on the second forward wheel.
Establish wheels and lower the car on the earth. Having cleared the ridge basis of heads of bolts, tighten fastening bolts the moment of 120 N · m.
Several times press a brake pedal that brake shoes nestled on a brake disk.
Check the level of brake fluid in a tank and if necessary add.
After installation of new brake shoes avoid sharp braking the first 200 km of a run of the car.