Under the influence of high temperatures inside the engine compartment, the rubber and plastic hoses that ensure the operation of various engine units gradually harden and deteriorate. It is necessary to periodically check the condition of the hoses, the presence of cracks and hardening, loose connections, and loss of tightness. The procedure for checking the cooling system hoses is described in subsection 2.11.
Some hoses are fastened with clamps. Check the tightness of the clamps, as loosening of the fastening leads to a breach of the tightness. In those places where clamps are not provided, check the reliability of the hose seal on the fittings, loss of elasticity in such connections due to swelling or hardening of the hoses is not allowed, otherwise the tightness of the connection is broken.
Vacuum hoses
Vacuum hoses can be identified by their color or by colored stripes glued to them. Vacuum hoses with different wall thicknesses, resistance to atmospheric pressure compression, and heat resistance are used for different engine systems. When replacing, make sure that the new vacuum hoses exactly match the ones being replaced.
Often, a hose can only be checked after it has been removed from the vehicle. If several hoses are being removed, mark the mating fittings and hoses first to avoid disturbing their relative position later.
When checking the condition of the vacuum hoses, also inspect the plastic tees. Check for cracks on them, as well as deformation of the hose where it meets the tee fitting, which may be the cause of a leak.
To check for leaks, listen through a section of hose with an internal diameter of about 6 mm, placing the hose on the place being checked. A characteristic "hissing" will indicate the presence of a leak.
Fuel hoses
Check the condition of the rubber fuel hoses for damage.
When replacing the fuel line on injection engines, the new line must exactly match the one used in the fuel system of the engine of this type.
When replacing hoses, always install screw-type clamps.
Metal tubes
Metal tubes are commonly used in the fuel line. Check the tubes for twisted sections and small incipient cracks.
When replacing, only seamless steel tubes should be installed. Copper or aluminum tubes are not suitable, as they cannot withstand vibration loads from the engine.
Check the condition of the metal tubes and fittings of the brake hydraulic system at the points of connection with the main brake cylinder and the dispenser; the presence of cracks and loose connections is not allowed.