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3-15-proverka-tormoznojj-sistemy.html
3.15. Check of brake system
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Remember that developed when functioning brake mechanisms the dust can contain extremely unhealthy the person asbestos. At all do not blow off a dust the compressed air and do not inhale it, at service of mechanisms put on a protective mask or a respirator. At all do not use for rubbing of components of brake system gasoline or solvents on an oil basis — apply only firm cleaners or methyl alcohol! |
The condition of components of brake system, besides regular, stipulated by the schedule of routine maintenance, checks, should be estimated each time at removal of wheels or at emergence of signs of violation of serviceability of functioning of brake system.
The symptoms listed below can be a sign of malfunction of components of brake mechanisms:
- When braking the car loses course stability (there is a withdrawal in one of the parties);
- During braking brake mechanisms publish squeal or a scratch;
- Excessively the course of a pedal of a foot brake increases;
- When squeezing a brake pedal pulsations are felt;
- Traces of leakage of brake liquid (usually on an internal surface of disks of wheels and tires) take place.
Disk brake mechanisms
Brake mechanisms belong to type self-regulating, compensation of wear of frictional slips occurs automatically at each squeezing of a pedal of a foot brake.
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The support of each of brake mechanisms is equipped with two blocks (internal and external). End faces of blocks are well looked through through a special observation port in the support case after wheel removal. |
Blocks of disk brake mechanisms of forward wheels on the Infiniti models are equipped with wear indicators. At wear of frictional slips over an admissible limit brake mechanisms during movement of the car start to publish high-frequency squeal, regardless of that, braking is made or not.
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It is not necessary to confuse the squeal published by indicators of wear in time from time by squeal arising at braking of blocks, defined mainly weather conditions and a driving manner. |
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- The assessment of residual thickness of a frictional overlay of an internal block is made visually through an observation port of a support. If slips are worn-out over an admissible limit (see. Specifications to Head Brake system), it is necessary to make complex replacement of brake shoes.
- If visually to estimate residual thickness of blocks it appears inconveniently, or there is a need for more detailed survey of blocks, remove a support (ы) and take blocks for more detailed studying.
- After blocks will be taken from a support, clear them by means of special means and check residual thickness of slips by means of a ruler or equipped noniusy a calliper.
- By micrometer measure thickness of brake disks. Compare results of measurements to standard requirements. If the thickness any leaves disks abroad an admissible range, replace it. If thickness of a disk in norm, check its general condition. Pay attention to such defects as deep scratches, furrows, teases, overheat traces, etc., in case of need remove a disk and send him to a pro-point.
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- Before establishing to the place of a wheel, examine all brake lines on existence of signs of damages, wear, destruction as a result of aging of a material, traces of leaks, bends, twisting and other deformations (in particular near points of connection of flexible brake hoses to supports of brake mechanisms). Check reliability of fastening of hoses collars. Make sure that any of brake hoses do not adjoin to acute angles of the body elements located in the neighbourhood, components of system of production of the fulfilled gases and a suspension bracket (at any provisions of a steering wheel). In case of need make the corresponding repair or correct a route of laying of lines. Defective components replace.
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Drum-type brake mechanisms
These mechanisms also are self-regulating — the corresponding adjustments are made each time when raising the parking brake.
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- At check of back drum-type brake mechanisms make sure that the parking brake is released, then обстучите a drum outside by a hammer with soft brisk for the purpose of weakening of landing.
- Remove brake drums.
- Make careful cleaning of brake mechanisms with application of special cleaning structure.
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At all do not blow off a brake dust from a surface of components the compressed air and do not inhale it — the dust can contain unhealthy asbestos! |
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- Estimate residual thickness of frictional overlays of brake boots (forward and back). The thickness of a slip is measured from an external surface and to a metal substrate (kleeny slips), or to heads of rivets (riveted slips). In the first case limiting admissible value makes 3 mm, in the second — 1.6 mm. In case of need make complex replacement of boots. Boots are subject to replacement also in case of identification of cracks, zapolirovanny to shine of sites of slips, or traces of hit of brake liquid.
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- Make sure of correctness of connection and serviceability of a condition of all springs of assembly of the brake mechanism.
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- Check assembly components on existence of traces of leakages of brake liquid. Having carefully hooked a finger or a small screw-driver, remove rubber boots from the wheel cylinder in the top part of boots.
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- Identification of any signs of leaks in these parts demands carrying out immediate regenerative repair of assembly of the cylinder. Also check on existence of traces of leaks all brake hoses and their shtutserny connections.
- Carefully wipe internal surfaces of a drum the pure rags impregnated with methyl alcohol. Try not to inhale a brake dust containing asbestos.
- Examine a working surface of a drum on existence of cracks, задиров, traces of an overheat and other damages. If defects cannot be removed with a way of processing of a surface a fine-grained emery paper, it is necessary to give a drum for a pro-point to a car-care center workshop.
- Repeat procedure for components of the opposite brake mechanism. Establish into place drums, fix wheels and lower the car on the earth.
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Vacuum amplifier
Check of serviceability of functioning of the vacuum amplifier of brakes is made from a driver's place.
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- At completely squeezed out pedal of a foot brake start the engine — the pedal should fail a little more.
- At the working engine several times squeeze out a pedal of a foot brake. The size of a course of a pedal should remain a constant.
- Squeeze out a pedal, muffle the engine and continue to hold a pedal pressed during about 30 more seconds, during which it should not neither fail below, nor rise.
- Again start the engine, let's to it work for about a minute, then again muffle. Again several times firmly squeeze out a pedal — the size of a course should be reduced with each muscleman.
- In case of negative result of the described check the servo-driver of the vacuum amplifier of brakes is subject to replacement.
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Parking brake
The hummock drive of the parking brake influences executive levers of brake mechanisms of back wheels of the car.
Design of a hummock drive of the parking brake
Management of the parking brake is made by means of the lever established between forward seats.
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- Having pulled the lever, cock it against the stop, having counted thus number of clicks of the ratchet mechanism. If the number of clicks leaves limits of an admissible range (see in the same place), the drive of the parking brake is subject to adjustment.
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Alternatively check of serviceability of functioning of the parking brake can be made by a car parking on a site of the road going under a bias and fixing by its motionlessly parking brake at the neutral provision of a transmission. If the brake does not hold the car when raising its lever on demanded number of clicks, it is necessary to make adjustment.
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