The maintenance of the fuel tank is mainly combined with the first-level maintenance of the car, releasing the accumulated water and dirt in the fuel tank, and checking whether there is oil leakage at the oil pipe joints and switches. For the fuel tank cap equipped with air valve and steam valve, also check whether the vent hole is unobstructed. The filter screen of the fuel filler should be kept intact - to prevent impurities from entering the fuel tank and blocking the fuel circuit when fueling. The gasket of the fuel filler cap should also be intact to prevent the oil in the fuel tank from overflowing during driving.
After the car has been used for a period of time, a thorough cleaning and overhaul of the fuel tank should be carried out. When cleaning the fuel tank, rinse the interior with hot water and dry it with compressed air to remove the gasoline vapor inside the fuel tank. Then, immerse the gasoline tank in an aqueous solution containing 10% sodium hydroxide, and rinse the inside and outside of the tank with running water after immersion. It can also be washed with 5% caustic soda boiling water solution, and then rinsed with hot water. If there is rust on the outside of the tank, brush it with a wire brush and then paint it. After the fuel tank is cleaned, it is necessary to check the tightness. When checking, plug all the orifices of the fuel tank with rubber plugs and then immerse them in water, and input compressed air from the oil pipe joint hole. Weld repair after painting.
During welding repair, different welding methods can be used for welding repair according to the size and location of the leak. If the leakage hole is not large, it can be repaired by soldering; if the leakage hole is too large, it should be repaired by patch welding; if there is a crack at the joint of the upper and lower half shells of the gasoline tank, the float of the fuel tank cover and the fuel gauge sensor should be fixed before welding. The group end caps are removed and the tank is filled with cold water to prevent explosions. When welding, use gas welding to cut the weld with a width of 2 or 3 mm at the welding repair place, and then use gas welding to repair it. After welding, trim the weld with a file.
If there is a large depression in the wall of the fuel tank, an iron rod can be welded in the depression, and the depression can be pulled out to repair. The repaired fuel tank should be tested for tightness again.