The maintenance of the fuel tank is mainly combined with the first-level maintenance of the car, to release the accumulated water and dirt in the fuel tank, and to check whether there is oil leakage at the oil pipe joints and switches. For fuel tank caps equipped with air valves and steam valves, check whether the vent holes are unblocked. The filter screen of the fuel filler port should be kept intact-lest impurities enter the fuel tank and block the fuel path when fueling. The gasket of the fuel filler cap should also be intact to prevent the oil in the fuel tank from overflowing when driving.
After the car has been used for a period of time, perform a thorough cleaning and overhaul of the fuel tank. When cleaning the fuel tank, flush the interior with hot water and blow it dry with compressed air to remove the gasoline vapor inside the fuel tank. Then, put the gasoline tank into an aqueous solution containing 10% sodium hydroxide to soak, 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 washed with hot water. If there is corrosion on the outside of the fuel tank, brush it with a wire brush and 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 immerse them in water, and input compressed air from the oil pipe joint holes. If there are bubbles in a certain part, it is a leak. At this time, mark the leak, except Welding repair after painting.
During welding repair, different welding methods can be used for welding repair according to the size and position of the leak. If the leak hole is not large, it can be repaired by soldering; if the leak hole is too large, patch welding shall be applied; if there is a crack in the joint between the upper and lower half shells of the gasoline tank, the fuel tank cap and the float of the fuel gauge sensor shall be installed before welding. Remove the group end cover and fill the oil tank with cold water to prevent explosion. When welding, use gas welding to cut off the weld with a width of 2, 3 mm at the place where welding is needed, and then use gas welding to repair. After repairing, use a file to repair the weld.
If there is a large depression in the wall of the fuel tank, an iron rod can be welded to the depression and the depression can be repaired. The repaired fuel tank should be tested again for tightness.