General issues
Attention! A/C hose replacement should be performed at a General Motors dealer or A/C service facility that has the equipment to safely depressurize the system. Never remove parts or hoses from the air conditioning system (see illustration), until the system is depressurized.
10.1. A/C hoses are easily identified by the metal tubes used at each joint (one of them is indicated by an arrow). Do not disconnect or accidentally damage these hoses (the system is under high pressure)
2. High temperatures under the hood can cause degradation of the rubber and plastic hoses used in the engine, auxiliary systems and exhaust system. Hoses should be checked periodically for cracks, loose clamps, hardening of materials, and leaks. Information pertaining to the coolant hoses can be found in section 9.
3. Some (But not all) hoses are attached to the nozzles with clamps. Where clamps are used, check and ensure that they have not lost tension to prevent leakage. If clamps are not used, make sure the hose has not expanded or hardened where it is placed over the fitting.
Vacuum hoses
4. Often vacuum hoses, especially those used in exhaust systems, are color coded or identified by colored stripes molded into each hose. Different systems require hoses with different wall thicknesses, different compression strengths and different temperature resistances. When replacing hoses, make sure the new hoses are made from the same material as the old ones.
5. Often the only effective way to check a hose is to remove it from the vehicle. If more than one hose is removed, be sure to mark them and the nozzles so that you can then correctly install them in their original place.
6. When checking vacuum hoses, be sure to include all plastic tees in the test. Check the nozzles for cracks and inspect the hoses where they meet the nozzle for any deformation that could lead to leakage.
7. A small piece of 1/4 in. ID vacuum tube can be used as a stethoscope to detect vacuum leaks. Press one end of the tube to your ear and touch the vacuum hoses and fittings, trying to hear the hissing sounds characteristic of an air leak.
Attention! When testing with a vacuum hose stethoscope, be careful not to allow your body or hose to come into contact with moving engine parts such as drive belts, fan, etc.
Fuel hose
Attention! Gasoline is flammable, so take all precautions when working on any part of the fuel system. Do not smoke or leave open flames or unprotected lamps in the work area, do not work in the garage with appliances and devices powered by natural gas (such as titanium or dryer), if there is a burning wick. If you spill any gasoline on your skin, wash it off immediately with soap and water. Wear safety goggles and have a fire extinguisher handy when doing any work on the fuel system. The fuel system is under pressure, so if any lines need to be disconnected, the system must first be depressurized (more information is available in chapter 4).
8. Check all rubber fuel hoses for wear and tear. Check specifically for cracks where there are hose bends and look directly at the junction points, such as where the hoses attach to the fuel filter and fuel injection unit.
9. When replacing the fuel hose, use a high quality fuel hose, usually type "Fluroelastomer" (what is on the hose). Under no circumstances should unreinforced vacuum lines, plastic pipes or water pipes be used as fuel hoses.
10. Normally, spring type clamps are used on the fuel lines. Over time, they lose their elasticity, therefore, with any replacement of the hose, they are replaced with clamps with a screw.
Metal pipelines
11. Steel pipe sections are often used as the fuel line between the fuel pump and the fuel injection unit. Carefully inspect them for cracks, jams, or other defects.
12. If a section of metal piping needs to be replaced, only seamless steel piping can be used, as copper and aluminum are not strong enough to withstand engine vibration.
13. Check the metal brake pipes where they enter the brake master cylinder and the ABS unit (if it exists) for cracks in pipelines and loose fittings. Any sign of a brake fluid leak requires immediate attention and a thorough inspection of the brake system.