11.4. Service of back drum brake mechanisms
Removal and dismantling
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- Car back also establish to Poddomkratta it on props. Block wedges both forward wheels.
- Remove a back wheel and the brake drum.
- In case of problems screw two bolts of M8 x 1.25 mm in carving openings in a drum and gradually tighten them, pushing away a drum from a half shaft flange.
- For simplification of the subsequent assembly try to remember the adjusting provision of components of the brake mechanism.
- Squeeze the directing springs of fastening of boots on a brake board, turn on 90 ° and remove holders (plates of springs), then remove from brake assembly of a spring, a saddle of springs and fingers (components of the drum brake mechanism of a back wheel are shown on an accompanying illustration).
- Disconnect from boots the lower coupling spring and a support from brake assembly.
- Disconnect and remove the top coupling spring.
- Part the top ends of boots in the parties, taking away them from pistons of the wheel cylinder, then take off boots from a brake board.
- Remove an adjusting spring and a razzhimny level from boots.
- If you are going to replace boots, remove a lock ring and an adjusting arm from the inside of a boot.
- Disconnect a brake tube from the wheel cylinder, give fixing bolts and remove the cylinder from a brake board.
- Remove boots, pistons, cuffs and springs from the wheel cylinder.
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Cleaning and check of a condition of components
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- Estimate degree of wear of frictional overlays of brake boots. If thickness of slips is less admissible (see size tables and adjustments at the end of the Management), they should be replaced, or to establish new boots.
- If the residual thickness of slips does not go beyond norm, examine them on existence of traces of pollution by oil or lubricant, in case of identification of those - replace.
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Replacement of slips is made in a set on four. |
- Check brake drums for existence of cracks, scratches, zadir and emergence of ovality. In case of need pierce drums or replace them.
- Wash out components of wheel cylinders methyl alcohol, then dry up them compressed air.
- Check pistons and mirrors of the cylinder for existence of cavities and signs of wear. In case of need to an otkhoninguyta the cylinder, or replace defective components.
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On the disassembled wheel cylinder remove the gate of pumping and check its passability. Without fail replace rubber boots and cuffs of pistons. |
- Compare efforts of stretching of returnable springs of brake boots to those for new, in case of need replace springs.
- Track that the ratchet wheel freely rotated on an adjusting razzhimny level. Screw it on a level against the stop.
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Assembly and installation
Assembly is made as it should be, the return to a dismantle order.
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- Grease cylinder mirrors, pistons and cuffs with pure brake fluid.
- Put on cuffs pistons sponges in the cylinder. Track correctness of an arrangement of cuffs in flutes of pistons.
- Omit assembly of the piston with a cuff in pure brake fluid, then insert it into the wheel cylinder. Track that sponges of a cuff were not turned out in the course of installation outside. Establish a spring and repeat the procedure for the second piston with a cuff. Put on the wheel cylinder on both sides boots.
- Install the wheel cylinder on a brake board. Screw and tighten fixing bolts with the required effort.
- Make sure of passability of a brake tube, then connect it to the wheel cylinder.
- There where it is required establish an adjusting arm and a lock ring from the inside of a boot and connect an adjusting razzhimny level and a spring to both boots.
- Part the top ends of boots that they were not hooked for pistons in the parties and establish assembly of boots on a board of the brake mechanism.
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- Establish fingers, saddles and the directing springs of brake boots on a board. Squeeze springs, put on holders (plates) and turn them for fixing of components on 90 °. Components of the drum brake mechanism are assembled shown on an accompanying illustration.
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- Connect the top and lower coupling springs to boots.
- Rotation of a ratchet wheel of an adjusting razzhimny level reduce boots together so that they entered a drum with a gap about 0:25 ÷ of 0.40 mm.
- Pump over the hydraulic brake system, establish wheels and lower the car on the earth.
- Make trial runs of the car, checking serviceability of its braking.
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