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There is something wrong with the brake of the loader, which should not be underestimated

Jul 21, 2018

With the rapid development of highway engineering construction and the gradual improvement of mechanization of maintenance, more and more construction units and an individual for rent have purchased various earth-rock machinery, especially the loader. A correct understanding of the braking system structure characteristics of these devices and the common troubleshooting methods can ensure the normal use of the equipment.


This paper takes the clamping disc brake system widely used in wheel loader as an example to explain its common faults and its troubleshooting methods.


1. Brake hairpin

Fault phenomenon: the loader has difficulty in starting and walking. After parking, it touches the clamp plate with hand and the clamp plate becomes hot. Main reasons :(a) the friction disc becomes thinner, the dustproof ring is damaged and water enters, and the piston is corroded and stuck. (b) the return spring in the booster pump is weak or broken, and the high pressure oil cannot be added.


2. Fault phenomenon: when stepping on the brake, an oil mist erupts.

Cause :(a) the brake lamp switch is damaged and the high pressure oil spurts out from the switch interface, which can be solved by changing the switch. (b) excessive length of piston rod of the booster pump. This kind of situation may occur in the new pneumatic pump assembly. The reason is that the piston rod is adjusted too long, which causes the piston stroke to be too large when the booster pump works. The piston working stroke should be measured during installation to determine the length of piston rod.


3. Run off after braking

The direct cause of off-track is the difference in braking torque between two wheels on both sides of the loader, and the common fault reasons are :(a) serious oil pollution on the brake caliper disc, severe reduction of friction system, and imbalance of braking torque. (b) the piston block of the partial pump cannot work. Stop the car on the brake, observe the operation of the sub - pump, as appropriate.


4. The pressure on the barometer rises slowly

Main reasons :(a) pipe leakage; (b) abnormal operation of the air pump; (c) corrosion and clamping of one-way valve; (d) the oil discharge bolts of the oil-water separator are not closed or the pressure regulating valve leaks air.

Troubleshooting method: first, pipe leakage should be eliminated, and then check the working state of the air pump. Remove the air pump out of the air pipe and press the air outlet with your thumb. If the pressure is low, the air pump is out of order. If the gas pump is in good working condition, then check the oil discharge screw plug or pressure regulating valve of the oil and water separator to avoid bypass, and troubleshoot through inspection. Finally, check the two one-way valves in the three-way joint, which may cause the gas reservoir to be unable to enter or slow.


5. Lack of power and weakness

Main reasons :(a) oil leakage of brake; (b) there is air in the brake oil road; (c) the hub oil seal is damaged and there is grease on the clamp disc; (d) serious wear and tear on braking and friction surface; (e) excessively low air pressure adjustment.

The above faults can be eliminated by repairing, adjusting or replacing parts according to their respective causes.