Contents: Checking the condition of the hoses…↓ General information ↓ Vacuum hoses ↓ Fuel lines ↓ Metal pipelines ↓
Checking the condition of the hoses in the engine compartment and replacing them
Warning. It makes sense to entrust the replacement of the air conditioner refrigerant pipes to a specialist from the dealership auto service center who has the equipment to remove the refrigerant from the system. Do not change tubes when the system is full.
General information
1. High temperatures in the engine compartment will greatly contribute to the deterioration of rubber and plastic hoses/tubes used in the engine, accessories and emission control system. Periodic inspections should identify cracks, loose clamps, damage to hose/tube materials and leaks.
2. For information regarding cooling system hoses, see paragraph 11.
(The original can be read on the website: TOYOTAMAN)
3. Some hoses are secured in the connections with clamps. When inspecting such hoses, check that the clamps are tight to avoid leaks. If clamps are not used in the connection, then during inspection, make sure that the hoses at the connection points have not expanded and/or hardened, which can also cause a leak.
Vacuum hoses
4. Typically, vacuum hoses, especially those in the emission control system, have corresponding colors or colored stripes. Depending on the purpose, they vary in wall thickness, tensile strength and temperature resistance. When replacing hoses, make sure that the new and replacement hoses are the same type.
5. In some cases, to fully check the condition of the hose, it is necessary to disconnect it. If you have disconnected several hoses, it is a good idea to label the removed hoses and their corresponding fittings to avoid any potential errors during subsequent installation.
6. When checking the vacuum hoses, don't forget to check the plastic connecting tees for cracks, and also make sure the hoses are seated correctly on the fittings without any distortions, which will help prevent leaks.
7. To detect damage to vacuum hoses, a small piece of vacuum hose with a diameter of 8-10 mm can be used as a stethoscope. Put one end of the "stethoscope" to your ear, and slowly run the other through the hoses and tees: a characteristic hissing-whistling sound will indicate the presence of microcracks.
Caution! When working with the vacuum stethoscope, be careful not to touch rotating engine parts such as drive belts, cooling fans, etc.
Fuel lines
Caution! Fuel is extremely flammable, so take special precautions when working on any part of the fuel system. Do not smoke or use open flames or portable electric lighting devices that are not equipped with protective screens. Do not work in a garage that uses gas-powered equipment, such as a water heater or clothes dryer. Since fuel is carcinogenic, wear protective gloves when working to avoid contact with the fuel on your hands. If fuel comes into contact with your skin, wash it off immediately with soap and water. Any fuel spilled on the floor must be wiped up immediately. Do not store contaminated rags left over from working with fuel in areas where ignition is possible. The fuel system maintains constant pressure. If you are going to disconnect any part of the fuel system, you must first relieve the pressure. When performing any work on the fuel system, wear safety glasses or a mask and keep a fire extinguisher handy.
8. Check all rubber fuel hoses for internal damage (soft to the touch outer surface) and abrasions. Also check for cracks where the hoses bend and where the hoses connect to the pipes, such as where the hose is connected to the fuel filter pipe.
9. When replacing, purchase only high-quality hoses specifically designed for use in fuel injection systems.
Caution! When replacing, use only hoses of the same type as those being replaced.
10. Spring type clamps are commonly used in the fuel system. Such clamps may become loose after some time, and when removed, they may "shoot" and fly off in an unknown direction. When replacing hoses, it is recommended to simultaneously replace all factory spring clamps with more reliable worm-type clamps.
Metal pipelines
11. Metal pipes are often installed in the section between the fuel pump and the fuel injection unit. When checking, make sure there are no bends, wrinkles or incipient cracks on the surface of the pipeline.
12. If any section of a metal pipeline is to be replaced, then only a new section made of seamless steel pipe must be used for this purpose. Copper or aluminum sections should not be installed as they are not strong enough to withstand engine vibration.
13. Inspect the metal brake lines leading to the master cylinder and brake proportioning valve (if it is used), and make sure there are no cracks on the surface of the pipeline and loose connections. Any signs of brake fluid leakage are a signal for an immediate inspection of the brake system.