Wash all parts in ethyl or methyl alcohol or clean brake fluid. DO NOT use mineral oils, gasoline, kerosene or carbon tetrachloride to wash brake system parts. Blow out all internal passages of parts with compressed air.
Inspect the pistons and bores of the wheel cylinders and the master cylinder for scoring, wear, or corrosion. Replace the unit if any of these defects are present. Inspect the calipers and wheel cylinders for fluid leaks and wear; if any defects are found, replace the unit with a new one.
When assembling, install only new sealing rings. They are usually supplied as a repair kit containing all the parts necessary to repair this unit.
Before installation, sealing rings, even new ones, should be carefully inspected. Make sure that the sealing lips are well formed, concentric with the seal bore, and have no sharp edges, surface defects or tears. Any seal that gives rise to any doubt should be discarded, no matter how small the defect may seem.
Preventing Brake Fluid Loss
When disconnecting hydraulic drive components, fluid will quickly leak out unless preventive measures are taken. To prevent fluid loss, it is recommended to seal the top of the master cylinder reservoir. For example, the vent at the top of the reservoir cap can be temporarily sealed with plasticine or something similar. Alternatively, you can remove the cap, cover the filler neck of the reservoir with a piece of polyethylene film and screw the cap on top. After this, the vacuum above the fluid will prevent it from leaking out of the disconnected tube.
In addition, you can clamp the disconnected brake hose with a special clamp (drawing O:8). These clamps are available at most auto parts stores. Cap the nipples of disconnected brake lines to prevent fluid from leaking out and dirt from getting in.
CAUTION: When you have finished working, do not forget to remove the clamps from the hoses and the seal from the master cylinder reservoir.
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Brake pipes and hoses
Inspect the brake pipes and hoses for corrosion, damage and fluid leaks, and replace them if defective. If the pipes are not tightly secured, they can vibrate, which leads to fatigue failure (cracks) of the pipes. Brake pipes are especially susceptible to rust on the side facing the body, so all dirt should be washed off when inspecting them.
When installing a new tube, do not tighten the fittings too much (with a torque of about 1.0 kg·m), because if you tighten the tube too much, the tube flare will be deformed, which can lead to fluid leakage. To avoid such damage, use only short wrenches when tightening the tubes.
Before installing the tube, make sure both sides of the connection are clean - any dirt particles that get inside can prevent the tubes from being securely connected.
After any work involving disconnecting pipes or hoses, it is necessary to bleed the brake system.
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