Attention! Air conditioning hoses should be replaced by a dealer or a specialist workshop that has the equipment to safely relieve pressure in the system. Never disconnect system hoses or remove components without first relieving pressure.
General information
Exposure to high temperatures in the engine compartment leads to the gradual failure of the rubber and plastic hoses used in various systems. Hoses should be checked regularly for cracks, loose clamps, hardening of materials and signs of leaks.
For information related to cooling system hoses, see Section Checking the functioning of the cooling system, and to the hoses of the brake system - in Section Checking the brake system.
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.
Vacuum hoses
Typically, vacuum hoses, especially those used in emission control systems, are color-coded or have colored stripe inserts.
Different systems require the use of hoses with different wall thicknesses, heat resistance and different collapse resistance. When replacing hoses, make sure that the material of the new hose matches the material of the old one.
Often the only reliable way to check the condition of a hose is to completely remove it from the vehicle. When removing more than one hose, ensure that the hoses and fittings are clearly marked to ensure correct assembly.
When checking the vacuum hoses, be sure to also check the T-shaped plastic connections. Inspect them for cracks that could cause leaks.
To check for vacuum leaks, you can use a small piece of vacuum hose as a stethoscope. Hold one end of the hose to your ear and listen to all vacuum hoses and connections with the other end for a characteristic hiss that indicates a vacuum leak.
Attention! When using such a stethoscope, be careful not to come into contact with moving parts in the engine compartment, such as the drive belt, cooling fan, etc.).
Fuel hoses
Attention! Certain safety precautions must be observed when inspecting or servicing fuel system components. 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. 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.
Fuel hoses are usually under pressure, so when disconnecting them, be prepared for fuel to splatter and need to be collected.
Attention! On vehicles equipped with a fuel injection system, the pressure in the system must be relieved before servicing the fuel hoses. See Chapter for instructions Power supply and exhaust systems.
Check all rubber fuel hoses for signs of wear and tear. Pay particular attention to bends and in front of fittings, such as the connection between the hose and the fuel pump or filter, where cracks can form.
Use only high quality fuel hoses. Never, under any circumstances, use non-reinforced vacuum hoses, clear plastic tubes, or water hoses as fuel.
Band-type clamps are commonly used to secure fuel hoses. These clamps loosen tension over time and may «jump out» upon removal. When replacing hoses, replace these clamps with screw-type clamps.
Metal lines
Sections of metal tubing are often inserted between the fuel pump and the fuel injection system. Check these tubes carefully for dents, twists, or cracks.
If a section of metal line needs to be replaced, use only seamless steel tubing as the copper and aluminum tubing is not strong enough to withstand the vibrations caused by the motor.
Check the metal brake lines where they connect to the master cylinder and pressure regulator or ABS (if it exists) for cracks or loose fittings. Any sign of a brake fluid leak requires an immediate overhaul of the entire brake system.
Power steering hoses
Check the power steering hoses for signs of fluid leakage, loose fittings and worn clamps. Leaking hoses and worn clamps should be replaced.