3-5-proverka-sostoyaniya-i-zamena-shlangov-i-trubok-v.html
3.5. Check of a state and replacement of hoses and tubes in a motive compartment, localization of leaks
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Replacement of hoses of the air conditioning system (K/V) should be made on HUNDRED or in a workshop with the equipment for safe dumping of pressure in this system. Never disconnect hoses of the K/V system and do not remove its components, previously without having dumped pressure. |
General information
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- Influence of high temperatures in a motive compartment leads to gradual failure of the rubber and plastic hoses used in various systems. It is regularly necessary to make check of hoses on existence of cracks, weakening of fastening of collars, hardening of materials and signs of leaks.
- Information relating to cooling system hoses is provided in the Section Check of Levels of Liquids, control of leaks, and to hoses of the brake system – in the Section Check of the Brake System and Coupling.
- The majority of hoses (but not all) fasten by means of collars. Where collars are used, check reliability of their tightening providing lack of leaks. If collars are not used, make sure that the hose in a junction with the union was not inflated and/or did not harden.
- If there are signs of leak of any liquid, but the type or an origin of liquid do not manage to be distinguished, leave the car for long time and put under it a big piece of paper or rags. It will help to find the place of course of liquid, and also to identify it on color. But keep in mind that some leaks can be shown only at the working engine.
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Vacuum hoses
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- Usually vacuum hoses which are especially applied in system of decrease in toxicity of the fulfilled gases (EGR) have color marking or inserts from color strips. Various systems demand use of hoses with various thickness of walls, thermal stability and various resistance to a collapse. When replacing hoses you watch that material of a new hose corresponded to material of old.
- Often only reliable way of check of a condition of a hose is its full removal from the car. At removal at the same time of several hoses mark their ends and unions to provide the correct assembly.
- When checking vacuum hoses do not forget to check T-shaped plastic connections also. Examine them on existence of cracks which can cause leaks.
- Leak in a vacuum hose means that air is sucked in in a hose (but does not leave a hose), and it does leak difficult for detection. For identification of leak of vacuum it is possible to use a small piece of a vacuum hose as a stethoscope. When the end of a hose directly is over the place of leak, the hissing sound will be clearly heard through it. Listen to all vacuum hoses and connections on existence of the characteristic hissing demonstrating leak.
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Using a similar stethoscope, be careful, do not allow contact with moving components in a motive compartment, such as driving belt, cooling system fan, etc. |
Fuel hoses
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At survey or service of components of fuel system it is necessary to observe certain precautionary measures. You perform all works in well aired room, do not allow approach of naked flame (for example, the lit cigarettes) or the lamps unprotected by the lamp shade to the venue of works. Immediately collect the spilled fuel by rags which put then to the place where its ignition is impossible. At hit of fuel on skin immediately wash away it a plentiful amount of water with soap. At work with fuel system it is necessary to use goggles and always to have near at hand the fire extinguisher. |
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- Fuel hoses usually are under pressure therefore at their detachment be ready to collecting the sprayed fuel.
- Check all rubber fuel hoses for existence of signs of wear and attritions. Pay special attention to areas of a bend and in front of unions, for example, a hose junction with the fuel pump or the filter, cracks can be formed there.
- Use only high-quality fuel hoses. Never use as fuel not reinforced vacuum hoses, transparent plastic tubes or water hoses.
- For fastening of fuel hoses collars of tape type are usually used. These collars weaken over time and can "jump out" at removal. When replacing hoses replace such collars with collars of screw type.
- Precisely it is difficult to define insignificant leak of fuel since fuel tends to evaporate quickly as soon as it contacts with air, especially in a hot motive compartment. Small drops can disappear before it is possible to define the place of leak. Metal unions contract when cooling, and rubber hoses at the same time will be weakened so possible leaks will be more obvious while the engine heats up at start from a cold state.
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Metal lines
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- Between the fuel pump and system of injection of fuel sections of metal tubes which should be checked for existence of dents, twisting or cracks carefully are established.
- If the section of the metal line needs to be replaced, use only seamless steel tubes since copper and aluminum tubes are insufficiently strong to resist to the vibrations caused by operation of the engine.
- Check metal brake lines in places of their connection with GTTs, the regulator the ABS pressure/activator for existence of cracks or the weakened nipple connections. Any signs of leak of brake fluid demand immediate careful survey of all brake system.
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