Caution: The replacement of A/C refrigeration hoses should be left to a car service workshop with the necessary equipment and qualifications to safely discharge the system. Never disconnect any refrigeration lines until the system is completely discharged!
Note: Detailed information on checking the condition of the hoses of the engine cooling and interior heating systems is set out in Section 10.
General information
Attention: Never disregard the detection of leaks of technical fluids, and the appearance of even small drips under the bottom of the car in the parking lot! Immediately carry out a complete and thorough check of all systems to avoid subsequent costly repairs!
1. Hoses tend to fail at the most inopportune moment. Exposure to high temperatures in the engine compartment leads to the gradual destruction of the rubber and plastic hoses used in various systems. Metal pipelines can be frayed when rubbing against protruding parts of the body or assemblies during vibration that occurs during engine operation or when the vehicle is moving. In order to avoid the trouble associated with rupture of hoses, they should be regularly checked for cracks, loosening of clamps and fitting connectors, abrasions, burn marks and signs of leaks.
2. Most hoses (But not all) fastened with clamps. Where clamps are used, check that they are securely fastened to ensure there are no leaks. If clamps are not used, make sure that the hose at the connection to the fitting has not swelled and/or hardened, allowing leakage. The use of homemade wire clamps, as well as careless tightening of tape clamps, can lead to gradual abrasion of the hose material - as soon as possible, replace such clamps with standard ones, preferably screw type.
3. If there are signs of leakage of any liquid, but its source cannot be recognized, then place a large piece of paper or cardboard under the car and wait for a while (long enough) time, this will help identify the source of the leak.
Note: Some leaks may only occur when the engine is running.
Vacuum hoses
4. Vacuum hose leak refers to air being sucked into the hose (but not out of it), and this makes the leak very difficult to detect. A small piece of vacuum hose can be used as a stethoscope to detect vacuum losses. When the end of the hose is directly over the leak, a hissing sound will be clearly audible through the hose. Listen to all vacuum hoses and connections for a characteristic hiss that indicates a leak. Contact with hot and moving parts must be avoided - the engine must be running when checking.
5. Often a reliable assessment of the condition of the vacuum hose can only be made by removing it from the vehicle. If you have to remove more than one hose, first take care to clearly mark them in order to ensure correct connection during assembly.
6. When checking the vacuum hose, do not forget to also evaluate the condition of its plastic fittings - inspect the fitting for cracks and make sure that the hose fits tightly on it. When pulled onto the fitting, the hose must not deform unevenly, causing vacuum loss.
Fuel hoses
Caution: When inspecting or servicing fuel system components, certain precautions must be observed. Perform all work in a well-ventilated area, keep open flames away (e.g. lit cigarettes) or light bulbs not protected by a lampshade to the place of work. Spilled fuel should be immediately collected with rags, which should then be put in a place where self-ignition is impossible. Try not to allow fuel to come into contact with exposed skin - prolonged contact of this kind can lead to the development of cancer. If fuel comes into contact with skin, wash immediately with plenty of soap and water. When working on the fuel system, wear safety goggles and always have a fire extinguisher handy.
7. Fuel lines and hoses are normally pressurized, so when disconnecting them, be prepared for fuel to splatter and must be collected.
Attention: Before servicing the fuel hoses, it is necessary to relieve the pressure in the fuel supply system (see chapter 4)! Dismantling of fuel system pipes equipped with injection can only be done at a service station!
Never, under any circumstances, use non-reinforced vacuum hoses, clear plastic tubes, or water hoses as fuel.
8. Check all rubber fuel hoses for signs of material aging and other defects. Pay special attention to the condition of the kink areas and areas immediately in front of the ends put on the fittings. Usually, spring-type clamps are used to fix the fuel hoses on the fittings. These clamps lose their firmness over time, moreover, they often unexpectedly come off at the moment the hose is disconnected. It would be wise to replace this kind of clamps with more reliable and safe worm or screw clamps.
9. Fuel leaks are difficult to pinpoint until the leak is significant and therefore easily visible. Fuel tends to evaporate quickly as soon as it comes into contact with air, especially in a hot engine compartment. Small drops may disappear before you can locate the leak. If you suspect that there is a fuel leak in the area of the engine compartment, then cool the engine and start it while it is cold with the hood open. Metal objects shrink when cooled, and rubber hoses tend to loosen, so any leaks will be more obvious while the engine is warming up on a cold start.
Metal lines
10. High pressure vehicle systems (e.g. in the fuel injection system or brake system) often sections of metal tubes are inserted or the entire system is made of them. Check these tubes carefully for dents, twists, or cracks.
11. If a section of metal line needs to be replaced, use only seamless tubing recommended by the manufacturer - non-standard tubing may not be able to withstand the stress of engine vibration.
12. Check the metal brake lines where they connect to the master cylinder and pressure regulator or ABS for cracks or loose fittings. Any sign of a brake fluid leak requires an immediate overhaul of the entire brake system.
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