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3-15-proverka-tormoznojj-sistemy.html
3.15. Check of the brake system
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Remember that the dust produced when functioning brake mechanisms may contain extremely unhealthy asbestos of the person. Do not blow off dust compressed air at all and do not inhale it, at service of mechanisms put on a protective mask or a respirator. Do not use for rubbing of components of the brake system gasoline or solvents on an oil basis at all — apply only company cleaners or methyl alcohol! |
The condition of components of the brake system, besides the regular, stipulated schedule of routine maintenance, checks, has to be estimated every time at removal of wheels or at emergence of signs of violation of serviceability of functioning of the brake system.
The listed below symptoms 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 leak of brake fluid take place (usually on an internal surface of disks of wheels and tires).
Disk brake mechanisms
Brake mechanisms belong to type self-regulating, compensation of wear of frictional slips happens 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 removal of a wheel. |
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 the movement of the car begin 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 wear indicators about time from time the squeal of blocks arising when braking determined mainly by weather conditions and a manner of driving. |
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- 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 the Head the Brake system), it is necessary to make complex replacement of brake shoes.
- If visually to estimate the residual thickness of blocks it appears difficult, or there is a need for more detailed survey of blocks, remove a support(s) and take blocks for more detailed studying.
- After blocks are taken from a support, clear them by means of special means and check the residual thickness of slips by means of a ruler or the caliper equipped with the nonius.
- Measure by a micrometer thickness of brake disks. Compare results of measurements to standard requirements. If thickness any of disks leaves abroad admissible range, replace it. If thickness of a disk is normal, check its general state. 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 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 also suspension brackets do not adjoin to acute angles of the body elements located in the neighbourhood, components of system of production of the fulfilled gases (at any provisions of a steering wheel). In case of need make the corresponding repair or correct a route of laying of lines. Replace defective components.
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Drum brake mechanisms
These mechanisms also are self-regulating — the corresponding adjustments are made every time at raising of the parking brake.
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- When checking back drum brake mechanisms make sure that the parking brake is released, then tap a drum outside the hammer with soft brisk for the purpose of weakening of landing.
- Remove brake drums.
- Make careful cleaning of brake mechanisms with use of the special cleaning structure.
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Do not blow off brake dust from a surface of components compressed air at all and do not inhale it — dust may contain noxious to health asbestos! |
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- Estimate the residual thickness of frictional overlays of brake boots (forward and back). Thickness of a slip is measured from an external surface and to a metal substrate (glued slips), or to heads of rivets (riveted slips). In the first case extreme 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 gloss of sites of slips, or traces of hit of brake fluid.
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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 for existence of traces of leak of brake fluid. Having carefully hooked a finger or the 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 recovery repair of assembly of the cylinder. Also check all brake hoses and their nipple connections for existence of traces of leaks.
- Carefully wipe the internal surfaces of the reel with the pure rags impregnated with methyl alcohol. Try not to inhale the brake dust containing asbestos.
- Examine the working surface of the reel on existence of cracks, zadir, traces of an overheat and other damages. If defects cannot be removed by processing of a surface with a fine-grained emery paper, the drum should be given for a pro-point to a workshop of car service.
- Repeat the procedure for components of the opposite brake mechanism. Install into place reels, 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 the driver's place.
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- At completely squeezed out pedal of a foot brake start the engine — the pedal has to fail a little more.
- At the working engine several times squeeze out a pedal of a foot brake. The size of the course of a pedal has to remain a constant.
- Squeeze out a pedal, kill the engine and continue to hold a pedal pressed within about 30 more seconds during which it should not neither fail below, nor rise.
- Again start the engine, let's it work for about a minute, then again muffle. Again several times firmly squeeze out a pedal — the size of the course has to 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 the hummock drive of the parking brake
The control of the parking brake is made by means of the lever installed between front seats.
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- Having pulled the lever, cock it against the stop, having counted at the same time the number of clicks of the ratchet mechanism. If the number of clicks comes out limits of 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 in the way of the parking of the car on the section of the road and fixing going under a bias its not movably parking brake at neutral position of the transmission. If the brake does not hold the car at raising of its lever on the required number of clicks, it is necessary to make adjustment.
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