Semi trailer inspection and maintenance essentials， Let's learn about it with Semi Trailer Manufacturers.
(a) matters needing attention during inspection
1, normally check, in addition to the provisions are empty state.
2. When picking up the wheel, two axles should be lifted at the same time. The jack position should be near the leaf spring, and the part in contact with the jack should be padded with thick steel plate or thick wood to prevent local force or even slip.
(2) Brake device inspection
1. Check the pipes of the brake system
(1) Connect the semi-trailer braking system and the tractor braking system.
(2) Raise the air pressure to the specified pressure, and check the air pressure from the barometer in the cab of the tractor or by installing a pressure gauge in the emergency braking system. The semi-trailer is a double pipeline air brake device (the rated pressure of the semi-trailer gas storage tank is 637~735kpa).
The brake system of the semi-trailer shall be in the state of full braking when compressed air is pumped into the rated air pressure (588±19.6kpa). Check the pipe joints, each valve assembly and the gas storage tank, etc. No air leakage phenomenon shall occur. Stop the air supply and be in the state of non-braking. In 15 minutes the pressure drop is not more than 29.4kpa. If the pressure drop exceeds the specified value, the cause of the leak should be identified and repaired.
(1) If the pressure drop exceeds the requirement, apply soapy water to the connection part of the pipeline to check whether there is air leakage. If there is air leakage, tighten the part or replace the corresponding parts.
(2) Close the transfer switch of the tractor control system, and then remove the compressed air hose of the semi-trailer control system to check whether the automatic braking is possible. If the braking is not possible, it indicates that the emergency relay valve is faulty.
(3) Then connect the control brake hose, open the transfer switch, and check whether the brake will be released automatically.
2. Check the emergency relay valve
(1) In the inspection of the braking system, there is no air leakage in each part of the emergency relay valve. The following methods can be used: in the emergency relay valve may leak in each part of the coating soapy water. in three seconds, the diameter of the soap bubble is not more than 3mm is considered normal.
(2) Check whether the exhaust gas is discharged from the exhaust port when the brake is released. If the exhaust gas is discharged, it is regarded as normal.
(3) if the action is not effective, the emergency relay valve should be repaired or replaced.
(4) When the semi-trailer travels for about 50,000 kilometers, grease should be added to the active friction surface and the groove of the 0 shape sealing ring. If the wear is serious, fresh parts should be replaced, and the dirt on the filter screen of the inflatable channel joint should be removed.
(5) The use of hand brake parking should be avoided as much as possible for a long time. Because of high time parking, it will make the release return spring of the relay valve compressed for a long time and reduce the elasticity, resulting in delay brake return and accelerated damage to the rubber seal ring. The water in the gas storage tank of the trailer should be discharged once a month.
(6) Open the three screws at the bottom of the relay valve, take out the exhaust return spring, open the clip spring with a caliper, take out the spool to check whether the seal ring is damaged, and replace it when damaged.
3. Check the brake air chamber
(1) When checking the brake work, check whether the push rod of the brake air chamber moves flexibly and whether the push rod stroke meets the requirements. If not, it should be adjusted.
(2) In the braking state and the non-braking state, the brake chamber should be checked for air leakage. If there is air leakage, tighten the joint.
4. Check the gas storage tank
(1) After parking, be sure to unscrew the water discharge screw plug at the bottom of the gas storage tank to discharge the internal water.
(2) When draining, the air in the tank will be discharged at the same time. If the exhaust is overly great, it should be re-inflated to keep the pressure in the tank at the prescribed value.
5. Check pipes and joints
Check the pipes and joints for cracks, damage, if any, should be repaired or replaced in time.
6. Adjust the main brake of the brake adjusting arm
Operate the brake chamber, check the working state of the brake adjustment arm, and check the air chamber travel. If the travel is too large, it means that the gap between the brake drum and the brake shoe is too large, and it should be adjusted at this time. The method is as follows: adjust the screw on the arm so that the center swing of the end hole of the brake arm is 15 "20mm. If the screw length is not sufficient, the adjusting arm can be removed from the camshaft, turn the next spline tooth, and then adjust after reset. After adjustment, lock the latch to prevent the brake arm from moving.