The decrease in torque conversion and speed change pressure of the compact wheel loader will cause the loader to work weakly. To eliminate such faults, attention should be paid to whether the needle bearing of the pump assembly is abnormally worn, the filter element fixed to the transmission housing is dirty, causing the filter element to be blocked, and whether the oil supply pressure is insufficient.

1. System pressure drop

The normal working pressure of the torque conversion and speed change system of the FL460 loader is between 1.0 and 1.6 MPa. When the pressure drops below 1.0 MPa, the loader will work weakly and have difficulty walking.

The main causes of such faults are as follows:

(1) The hydraulic transmission oil of the loader torque converter is not filled according to the instructions, but unqualified hydraulic transmission oil is added at will.

(2) The filter element fixed to the transmission housing is dirty, causing the filter element to be blocked and the oil supply pressure to be insufficient.

(3) The iron particles produced by the abnormal wear of the thrust bearing and thrust ring of the hydraulic loader torque converter cause the distribution valve in the valve assembly to be stuck, causing internal oil backflow.

(4) The valve stem of the distribution valve of the valve assembly is worn, causing internal pressure relief.

(5) The iron particles produced by the abnormal wear of the ball bearing and thrust bearing in the gear set cause the distribution valve to jam and cause the oil inside to flow back.

(6) The needle bearing of the pump assembly is abnormally worn, causing the driven gear to have a slight longitudinal displacement during operation and the oil supply volume to change.

(7) The contact surface between the pump body, pump cover and the main and driven gears in the pump assembly is worn, and the inner cavity oil is relieved.

The following points should be noted to eliminate such faults:

(1) Qualified hydraulic transmission oil should be replaced according to the instructions and replaced in time.

(2) The filter element fixed to the transmission housing should be maintained or replaced on schedule.

(3) The torque converter of the loader should be disassembled and inspected regularly, and the thrust bearing and thrust ring should be replaced in time.

(4) The valve stem of the valve assembly can be treated with spraying technology. The disadvantage is that the service life is very short and the valve assembly can also be replaced.

(5) The needle bearings and thrust bearings of the gear set should be disassembled and inspected regularly. It is recommended to replace the bearings within one overhaul cycle. If they are used forcibly, the gears may be abnormally worn or broken, causing greater economic losses.

(6) The needle bearings of the pump assembly must be replaced in time after abnormal wear. Since it is difficult to purchase this accessory individually, the assembly is generally replaced.

(7) The contact surfaces of the pump body, pump cover and the main and driven gears of the pump assembly are generally repaired by grinding after wear, and the grinding amount is not more than 0.5 mm.

2. Oil overheating

The slippage of the clutch in gears Ⅰ, Ⅱ and reverse is the main cause of oil overheating. In severe cases, the housing is hot and oil sprays out from the refueling port of the loader torque converter.

The reasons for the high oil temperature in the torque converter and transmission are as follows:

(1) The friction plate is excessively worn, the surface lubricating oil groove becomes shallower, and the heat dissipation effect is reduced due to the reduction in the amount of oil passing through.

(2) The quality of domestic friction plates is unqualified, resulting in premature wear and overheating of the oil temperature.

(3) When assembling the clutch, the friction plates and steel plates should be assembled strictly according to the specified number. If one friction plate or one steel plate is installed less for the convenience of assembly or to reduce costs, although it can still be used temporarily, it may cause the oil temperature to rise.

The following points should be noted when eliminating such faults:

(1) When disassembling and inspecting, the wear depth of the friction plate oil groove cannot be greater than 0.1mm; the unevenness of the warping of the steel plate cannot be greater than 1mm. If it exceeds the repair limit, it should be replaced in time.

(2) Although replacing the original imported friction plate is expensive, it can ensure that it meets the working technical requirements of the original machine.

(3) Assemble the friction plates and steel plates according to the number required by the original machine.

3. Leakage at the connection of the torque converter front cover of the loader

The main reasons for oil leakage at the connection between the torque converter front cover of the hydraulic wheel loader and the transmission front cover housing are: the O-ring is damaged during assembly; the screws at the connection are loose; the O-ring quality is unqualified.

Since it is cumbersome to deal with this leak, it is recommended to install an imported O-ring.

4. Difficulty in shifting gears

The FL460 loader cannot shift gears, which is generally caused by the change in the lateral displacement between the distribution valve and the tie rod. The specific reason is mainly the wear of the tie rod ball head or the loosening of the adjustment lock cap. If the above fault occurs, the adjustment tie rod should be checked and adjusted.