11.3. Service of forward disk brake mechanisms
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Implementation of the procedures described below will require the following special tools: the dial measuring instrument (for check of size of a beating of a disk), a vernier caliper (for measurement of thickness of a disk) and a steelyard (for measurement of effort of a prikhvatyvaniye of brakes). |
Check of a state and replacement of brake shoes
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- Car front also establish to Poddomkratta it on props. Remove forward wheels.
- Through an observation port in the support case (see an accompanying illustration) estimate the residual thickness of frictional overlays of brake shoes. If thickness of a slip any of blocks is less admissible (see size tables and adjustments at the end of the Management) or if blocks are polluted by lubricant or brake fluid, it is necessary to make replacement of all four blocks on brake mechanisms of both wheels.
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If blocks are polluted, it is necessary to find out and remove the cause of leaks also. |
- By means of the syringe pump out about two thirds of nominal amount of brake fluid from the GTTs tank.
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The used liquid is not subject to the repeated use. |
- Removal of liquid is made for the purpose of the prevention of its overflowing too much of the tank at an utaplivaniye of pistons of supports for replacement of blocks.
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Do not delete all liquid as it will cause need of pumping of hydraulic system from the tank. |
- Give a bolt of the lower directing finger and turn the support case up on the top finger (see an accompanying illustration), having opened access to brake shoes, adjusting laying and holders in an anchor bracket (a guide of blocks) of a support.
- Remember the adjusting provision of components and remove from an anchor bracket holders, blocks and adjusting laying.
- Check adjusting laying and holders for existence of signs of wear and damages. Replace defective components.
- Establish adjusting laying on blocks, then establish in an anchor bracket in the landing provisions blocks (with laying) and holders. Moderately grease holders with silicone lubricant.
- Push the piston perpendicularly into the support cylinder. In case of need use a clamp.
- Make sure of freedom of sliding of a support on the directing fingers, then lower it on blocks.
- Establish the lower directing finger and tighten its bolt with the required effort.
- After completion of replacement of blocks of both brake mechanisms, several times squeeze out a brake pedal for the purpose of shrinkage of blocks on disks. In case of need add brake fluid in the tank to the required level.
- Establish forward wheels and lower the car on the earth.
- Make trial runs of the car, having checked serviceability of functioning of brakes.
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Capital repairs of a support
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- Car front also establish to Poddomkratta it on props. Remove forward wheels. Components of a support of the forward disk brake mechanism are shown on an accompanying illustration.
- Give a nipple bolt and disconnect a brake hose from a support. Zakuporte the end of a hose in order to avoid hit in hydraulic system of dirt and for the purpose of minimization of losses of brake fluid.
- Give bolts of the directing fingers of a support and remove the case of the last from assembly of an anchor bracket.
- Press wooden whetstone to anchors of blocks of the case of a support and carefully squeeze out the piston of the support cylinder, giving air under low pressure to an opening under installation of a hydraulic hose on the support case.
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Excessive pressure of air can become the reason of pushing out of the piston with high speed that is fraught with getting injured and damage of the piston. |
- Remove a boot from the piston and take a piston cuff from the cylinder.
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For extraction of a cuff use the blunt tool which is preferably made of plastic or a tree. |
- Take the directing fingers and components of blocks from an anchor bracket.
- Wash out the cylinder of a support and the piston pure brake fluid.
- Check a cylinder mirror for existence of cavities, traces of corrosion, signs of wear and damages. In case of need replace the support case.
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Minor defects can be removed by means of a thin emery paper. |
- Check the piston for existence of cavities, traces of corrosion, signs of wear and damages. In case of need make replacement.
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Do not try to polish the piston with a thin emery paper as it will lead to damage of its facing layer. |
- Check a condition of components of blocks, guides of fingers and an anchor bracket. Replace defective parts.
- You will throw out all rubber components removed from assembly of a support.
- Grease a new cuff of the piston and a boot with lubricant for rubber components and establish a cuff in a cylinder flute. Track correctness of landing of a cuff in a flute, - it should not be overwound.
- Put on a boot the piston and grease the last with pure brake fluid.
- Completely drown the piston in the cylinder of a support and fix a boot in a flute on the edge of the cylinder.
- Grease the directing fingers and an internal part of their protective covers with lubricant for rubber components and establish assemblies of fingers with covers in an anchor bracket.
- Install components of blocks in an anchor bracket.
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- Pick up a steelyard to a hairpin of fastening of a wheel and measure effort of resistance of a nave to a provorachivaniye (see an accompanying illustration). Write down result of measurement. In case of need check adjustment of a pretightness of the stupichny bearing.
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- By means of the dial measuring instrument fixed on a component of a forward suspension bracket with the plunger pressed to a face surface of a brake disk measure disk beating size (see an accompanying illustration). If the result of measurement goes beyond admissible limits (see size tables and adjustments at the end of the Management), pierce a disk, or make replacement.
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- By means of a vernier caliper measure thickness of a brake disk in several points on forming. In case of need pierce a disk or replace it.
- Dress the support case on assembly of an anchor bracket, screw and tighten bolts of the directing fingers with the required effort. Connect a brake hose to a support and tighten a nipple bolt with the required effort.
- Pump over the hydraulic brake system.
- For five seconds squeeze out a brake pedal.
- Release a pedal and turn a nave of a forward wheel on ten turns.
- By means of a steelyard measure effort of resistance to a nave to a provorachivaniye.
- Subtract result of the first measurement from result of effort of a prikhvatyvaniye of a brake, the second for the purpose of definition. The maximum admissible value makes 7.2 kgfs, at its excess find the getting jammed components and make necessary repair.
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Removal and installation of a brake disk
Removal
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- Remove assembly of a nave of a forward wheel.
- Give fixing bolts and separate a disk from a nave.
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Installation
Installation is made upside-down.
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- Tighten bolts of fastening of a disk to a nave with the required effort.
- Adjust a pretightness of stupichny bearings.
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