3.15. Check of a state and replacement of hoses and tubes in a motive compartment, localization of leaks
Replacement of hoses of the air conditioning system (K/V) should be made on HUNDRED or in a specialized workshop where there is an 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.
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 given below, and to hoses of the brake system - in the Section Check of the Brake System.
The majority of hoses (but not all) fasten by means of collars. Where collars are used, check reliability of their fastening 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, allowing leaks.
If there are signs of leak of any liquid, but the type or an origin of liquid do not manage to be distinguished, then it is necessary to leave the car for long time and to put a big piece of paper or a rag under the car. 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.
Usually vacuum hoses which are especially applied in system of decrease in toxicity of the fulfilled gases 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 more than one hose mark hoses 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 very 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 a hose. Listen to all vacuum hoses and connections on existence of the characteristic hissing demonstrating leak.
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.
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 unprotected the lamp shade of lamps 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.
Fuel hoses usually are under pressure therefore at their detachment be ready to collecting the sprayed fuel.
On the cars equipped with system of injection of fuel before serving fuel hoses, it is necessary to dump pressure in system (see the Head of the Power supply system and production of the fulfilled gases).
Check all rubber fuel hoses for existence of signs of wear and attritions. Pay special attention to sites 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, under no circumstances 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 a tension 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 fuel leak until leak becomes essential and, therefore, easily visible. 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. About suspicion of existence of leak of fuel in the field of a motive compartment cool the engine and start it, it cold, at an open cowl so far. Metal objects contract when cooling, and rubber hoses will tend to weaken so any leaks will be more obvious while the engine heats up at start from a cold state.
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.
Hoses of the hydraulic booster of steering
Check GUR system hoses for existence of signs of leak of liquid, the weakened nipple connections and worn-out collars. The proceeding hoses and worn-out collars should be replaced.
Cooling system hoses
Leaks in the cooling system usually are found on white or colors of a rust to a raid in the area adjoining leak.
Carefully check a radiator and hoses of cooling liquid on all length. Replace hoses with cracks, gaps and signs of aging. It is easier to find cracks if to press a hose. Pay special attention to collars which attach hoses to cooling system elements. Collars of fastening of a hose which were strongly tightened can cause a gap or a puncture of a hose, leaks in the cooling system will be result of what. Examine all hoses and the surfaces of connection of hoses regarding leaks. If any problems of similar character with leaks are found, then replace this component or laying.