Tractor Fault Analysis

1. Fuel tank supply switch leaking: The cause is damage to the graphite and asbestos oil seals at the switch.
Elimination: 1. Remove the switch, take out the packing, make two round gaskets from oil-resistant rubber sheets with an outer diameter 1 mm larger than the switch housing hole and an inner diameter 1.50 mm larger than the handle screw rod, sandwich the rubber gasket between steel gaskets, then fit them together on the handle screw rod and tighten the gland device. 2. Wrap graphite and asbestos rope between the two steel gaskets and fill completely, then tighten the gland device.
2. Fuel tank drain cock leaking: The cause is rust or failure of the steel ball inside the cock.
Elimination: Replace the steel ball (diameter 15 mm, a steel ball from a bearing with an inner diameter of 80 mm can be used as a substitute).
3. Fuel pipe flare leaking: The cause is poor sealing between the flare cone surface and the flare seat.
Elimination: 1. When tightening the joint, first tighten the end with the flare. 2. After grinding the flare joint, apply sealant on the cone surface, then tighten or saw off the flare and re-expand it with an expander.
4. Hollow screw joint leaking: Causes are 1. Uneven end face of the fuel pipe joint and gasket; 2. Uneven screw hole on the housing.
Elimination method: Grind the joint and gasket flat. Machine the inner hex surface of the hollow screw flat, then tighten or apply sealant on both sides of the gasket.
5. Housing joint leaking: The cause of oil leakage at the joint surfaces of the oil pan, cylinder head, valve cover, timing gear cover, transmission cover, starter transmission cover, and other housings is usually due to loose fasteners, damaged or failed gaskets.
Elimination: 1. Regularly ensure fasteners are tightened. 2. For parts not frequently disassembled, such as paper gaskets, apply red sealant on both sides of the gasket; 3. For frequently disassembled parts like valve cover and filter housing joints, use asbestos gaskets coated with lead oil. When tightening, bolts should be tightened symmetrically in several stages. Also, ensure gaskets are intact, joint surfaces are flat and clean, and parts are properly aligned without deformation.
6. Leakage at control lever shafts: Causes are 1. Damaged sealing gasket; 2. Increased clearance between shaft and hole.
Elimination: Select suitable oil-resistant rubber gaskets based on shaft diameter, with an inner diameter 1-3 mm smaller than the shaft diameter, and install them on the shaft surface contacting the hole wall to press tightly.
7. Crankcase oil seepage: Causes are damaged paper gasket or loose screws.
Elimination: Remove the oil pan, take off the gasket for inspection. If the gasket is intact, clean and apply a layer of red sealant; if damaged, replace with a new gasket. Apply a layer of red sealant. Screws should be tightened symmetrically and evenly.
8. High-pressure oil pipe leaking: The cause is wear of the joint cone surface after long-term use, leading to poor sealing.
Elimination: Place a plastic tube segment 1-2 mm long and about 5 mm in diameter between the high-pressure oil pipe cone surface and the tapered hole, or use a purple copper gasket with an inner diameter slightly larger than the pipe inner diameter and appropriate outer diameter, or replace with a new high-pressure oil pipe.
9. Transmission gear oil leaking: Causes are 1. Excessive clearance between transmission bearing and shaft hole; 2. Oil seal wear and aging.
Elimination method: If the clearance between the housing shaft hole is too large, repair by sleeve insertion. If leakage is caused by oil seal wear or aging, replace the oil seal.
10. Support wheel, idler wheel, and guide wheel leaking: Causes are 1. Rubber sealing sleeve wear and aging; 2. Severe wear of the sealing ring.
Elimination method: Replace the rubber sealing sleeve promptly. Replace the large sealing ring. The two rough joint surfaces of the sealing ring should be properly ground and coated with a layer of graphite grease on both sides. After installation, do not allow water or dirt ingress for 24 hours of operation.
11. Oil filling and draining port leaking: Causes are 1. Inconsistent threads and pitches at sealing points of diesel tank, gasoline tank, hydraulic oil tank, diesel coarse and fine filters, high-pressure oil pump, oil pan, transmission, etc.; 2. Diesel tank cover lacks sealing rubber.
Elimination method: Ensure screws and pitches at sealing points are consistent, all using fine threads. Add sealing rubber.