Essentials for inspection and maintenance of low bed truck trailer

TITAN VEHICLE | 2020-05-19

1. Precautions during inspection

1. During normal inspection, the low bed truck trailer needs to be in an empty state.

2. When the wheel is to be lifted, the axle should be lifted at the same time, and the jack position should be near the leaf spring.

3. The parts in contact with the jack should be covered with thick steel plates or planks to prevent local stress or slipping.

Customers visits our factory and buys 3 line 6 axle low bed truck trailerCustomers visits our factory and buys 3 line 6 axle low bed truck trailer


2. Inspection of braking device

1. Check the whole and joint

  • Inspect all pipes and joints for cracks and breakage, and repair or replace them in time if necessary.
  • Connect the lowbed semi trailer braking system and the tractor braking system.
  • Increase the air pressure to 0.7 ~ 0.8MPa, and check the pressure from the pressure gauge of the tractor cab or the pressure gauge installed in the inflation pipe system.
  • Depress the brake pedal of the tractor and check whether the pressure drop exceeds 30kpa / min (the engine is not running).
  • If the pressure drop exceeds the standard value, apply soapy water to each pipe connection, and visually check whether the diameter of the air bubbles in the leaked part exceeds 25mm within 3 seconds. When the diameter exceeds 25mm, tighten the part or replace parts to prevent leakage gas.

2. Check the emergency relay valve

  • Turn off the inflatable pipeline connection switch, then remove the air connector, and check whether the brake is applied automatically. If it cannot be applied automatically, the emergency relay valve is faulty.
  • Whether there is air leakage in each part of the emergency relay valve, the soap bubble diameter does not exceed 7mm within 3 seconds, it is normal.
  • Check whether the exhaust is exhausted from the exhaust port when the brake is released. If yes, it means normal.
  • If the action fails, the entire emergency relay valve should be replaced.

3. Check the brake air chamber

When the brake is working, check whether the brake cylinder push rod moves flexibly and whether it is within the specified stroke (standard working stroke is 30 ~ 35mm). If the stroke exceeds 50mm, it should be adjusted.

In the braking state, check the brake air chamber for air leaks. Apply soapy water to the clamps to check for air leaks. If the air leaks, tighten the clamp clamping nuts with a tightening torque of 30 N.m. Check the front vent hole for air leaks. If air leaks, replace the rubber diaphragm. Inspect the exterior for cracks and damage, and replace the entire brake cylinder if necessary.

4. Check the gas tank

After driving, be sure to open the water drain valve at the bottom of the gas reservoir to drain the internal condensate. Turn the water valve for a few seconds to completely drain the internal condensate.

During the drainage, the internal gas will be discharged at the same time. If too much exhaust gas causes the emergency relay valve to act, the gas should be replenished to maintain the pressure in the gas cylinder at its prescribed pressure.

5. Adjustment of the brake

  • Operate the brake air chamber, check the working status of the brake adjustment arm, and check whether the stroke of the push rod is normal. If the stroke exceeds 50mm, it means that the gap between the brake shoe friction plate and brake drum is too large.
  • When adjusting the brake, first you press the positioning sleeve of the adjustment arm, move the small hexagonal head shaft.
  • Because it is difficult to ensure a consistent clearance when adjusting the wheel brakes, the test run after adjustment is based on the fact that the brakes do not deviate. For detailed adjustment method, please refer to the introduction in the axle manual.

100 ton low bed truck trailer axlex and tires100 ton low bed truck trailer axlex and tires

3. The axle

Inspect the axles, wheels and tires for cracks, damage and deformation, and repair or replace if necessary.

1. Adjustment of axle clearance

  • Use a jack to lift the low bed truck trailer.
  • Rotate the rim, tighten the lock nut with a torque of 400N.m, and then reversely turn 1 / 8-1 / 6 turns.
  • Rotate the rim, and gently tap the rim (position of the rim bearing) with a hammer to check whether the rotation is flexible.

2. Inspection and maintenance of tires

  • Whether the tire air pressure greatly affects the service life and safety of the tire, so the specified tire pressure should be maintained including the spare tire.
  • The tire wear varies depending on the load, road surface and braking conditions. In order to make tire wear more consistent, the tire assembly position should be exchanged regularly (every 5000 kilometers).
  • Check the tightness of the wheel nut every day. If looseness is found, tighten it. The tightening torque is 450 ~ 500N.m.

4. King pin and king pin seat plate

1. Check the traction pin for flaws, premature wear and cracks every day.

2. Measure the diameter of the traction pin. If the diameter is less than 48 or 86mm, it should be replaced if there is a crack or abnormal damage.

3. When the traction pin is changed or the traction pin is loose, the traction pin lock nut should be tightened, and the tightening torque is 1100 ~ 1300N.m.

4. Check the traction pin seat plate for damage, distortion and foreign matter, and repair or replace if necessary.

5. Electrical parts

1. Check if the terminal is slack, whether the wire is sagging and damaged, and repair or replace if necessary.

2. Inspect the car lights. If there are broken filament bulbs, lamp housing cracks and surface gloss damage, etc., they should be replaced.

6. traction seat and its parts

1. Check the traction seat panel for weld cracks and wear plates for severe wear.

2. Check whether the lock hook, wear ring and cross bolt are severely worn, deformed or loose.

3. Check whether the bolts of the support base and the connecting plate are loose, and whether the support base is damaged.

4. Check whether the rubber damping sleeve is damaged. The method is to use a crowbar to pry the joint between the saddle plate and the support seat. If the gap is large, the rubber shock-absorbing sleeve has been damaged.

5. Check whether the safety lock works normally and whether the lever mechanism is flexible or stuck.


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