1. Metal pipelines must not have nicks, scratches, burrs, active corrosion centers and must be located away from sharp edges that can damage them.
2. The brake hose must be elastic, without tears or cracks. The hose must be firmly sealed in the tips. The threads of the hose tips must not be damaged. If the hose swells when you press the brake pedal, then the cord threads are torn. If any of these defects are detected, the hose must be replaced. Hoses must not come into contact with mineral oils and greases that dissolve rubber.
3. All pipeline fastening brackets must be intact and well secured. Loosening of fastening or destruction of brackets leads to vibration of pipelines and, as a consequence, to their breakage.
4. Do not allow fluid to leak from the connections of the master cylinder with the tank and pipelines; if necessary, replace the tank bushings and tighten the nuts without deforming the pipelines.
Helpful Hint: It is recommended to use a special wrench for the brake pipe mounting nuts.
If any faults are found, replace damaged parts with new ones.
Flexible hoses, regardless of their condition, should be replaced with new ones after 125,000 km or five years of vehicle operation to prevent sudden ruptures due to aging.
[The article is taken from the website VAZbook.ru]