Publish Time: 2022-01-25 Origin: Wondee Autoparts
Installation and Use of Single Axle Lifting Type Semi Trailer Air Suspension
-Maintenance Cycle and Troubleshooting of Main Parts（Part 3）
1. Air suspension maintenance cycle
As shown in Table 1 below.
Normal use | Maintenance cycle | ||||
Inspection items | Inspection contents | Regular inspection | After the first load travel | Every three months or 25000 km | Every six months or 50000 km |
components | Visual inspection for damage and wear | ● | |||
Air bags | After driving on asphalt road in summer, driving on muddy road after rain and other harsh environments, check and keep the air bag and its piston (base) clean. | ● | |||
Check whether the airbag surface is damaged (cracked, worn, wrinkled, surface foreign matter intrusion, etc.) | ● | ||||
Check the fastening of airbag fastening bolts | ● | ● | |||
Pneumatic circuit | Check and maintain the cleanliness and integrity of the air filter | ● | |||
Check the air tightness of valve body and pipeline connection, whether the installation is tight and whether there is damage | ● | ● | |||
Shock absorbers | Check the tightness of the upper and lower pistons of the shock absorber | ● | ● | ||
Check the tightness of the shock absorber and replace if there is any leakage | ● | ● | |||
U-bolts | Check the tightness of the nuts of the U-bolts. If loose, tighten the nuts alternately diagonally | ● | ● | ||
Bolts of main beam and shock absorber | Check the locking condition of self-locking nuts of bolts of main beam and shock absorber | ● | ● | ||
Bushings | Slightly brake the semi-trailer to move forward and backward, or pry the main beam at the bushing with a pry bar. At this time, the main beam shall not be loose. Otherwise, the main beam or shock absorber bushing has been damaged. Replace it. | ● | |||
Lifting device | Check the fastening condition of lifting airbag fastening bolts and nuts. | ● | ● | ||
Air tanks | Check the working condition of the drain valve at the bottom of the air tank, and replace it if it is blocked. | ● | |||
(Table 1. Maintenance table)
Remark:
The road conditions and specific use conditions of vehicles in each country / region will be slightly different. The maintenance cycles in the above table are for reference only.
"●" means maintenance.
2. Troubleshoots of air suspensions
2.1 Troubleshoots of air bag assembly
As shown in Table 2 below.
Problems | Causes | Troubleshooting |
The airbag cannot be inflated | Airbag damage and air leakage | Replace the airbag |
Pneumatic circuit abnormal | Check and repair the pneumatic circuit system | |
Load Sensing valve damaged or improperly installed | Replace or Adjust the load sensing valve | |
Failure of the pressure protection valve and pressure limiting valve | Adjust or replace the valve | |
Airbag damage and base rupture | Gravel and other hard objects are drawn between the airbag and the base, causing friction | Replace the damaged parts, check and clean the airbag frequently |
The airbag was pierced by a hard object | Replace the airbag | |
Improper suspension mounting height | Replace the damaged parts and adjust the suspension height to the correct | |
Severely overloaded | Replace the damaged parts and load according to rated load | |
Improper installation of the suspension and chassis frame | Replace the damaged parts, adjust or reinstall the suspension | |
Friction between the tire or brake system components and the airbag | Replace the damaged parts, eliminate interference and reinstall | |
Friction between the brake chamber and airbag | Replace damaged parts and change the installation position of air chamber or clamp. |
(Table 2. Troubleshoots of airbags)
2.2 Troubleshoots of shock absorbers
As shown in Table 3 below.
Problems | Causes | Troubleshooting |
Shock absorber oil leakage | Long service time, failure, oil seal damage, broken at the welding position | Replace the shock absorber |
Shock absorber deformation | It is impacted abnormally, interferes with other parts, exceeds the stroke and stretched excessively | Replace the shock absorber |
At the maximum stroke, the piston is stuck and accidentally impacted during stretching | Replace the rubber block and baffle | |
The nut of the shock absorber falls off | The nut is not tightened to the specified torque | Tighten the nut to the specified torque |
Abnormal noise of shock absorber | The internal parts of the shock absorber are damaged | Replace the shock absorber |
(Table 3. Troubleshoots of shock absorber)
2.3 Troubleshoots of Load Sensing Valve
As shown in Table 4 below.
Problems | Causes | Troubleshooting |
The load sensing valve cannot correctly control the air inlet and exhaust of the airbag | There is no compressed air in the pneumatic circuit, or the valve is blocked by dirt, or the fastening screw of the regulating rod of the load sensing valve is loose, or the valve core of the load sensing valve is damaged | Check the air source, clean the load sensing valve, tighten the loose nut, or replace the load sensing valve |
Air leakage of load sensing valve | The sealing ring of the valve element is damaged | Replace the load sensing valve |
(Table 4. Troubleshoots of load sensing valve)
2.4Troubleshoots of Steel structural parts
As shown in Table 5 below.
Problems | Causes | Troubleshooting |
Welding seam broken | long-term alternating load, there are pores and slag inclusion in the welding seam. | Re-welding |
Main beam damage | Severely overloaded | Replace the main beam and load according to rated load |
Bad road conditions | Replace the main beam and drive slowly | |
Improper mounting height of suspension | Replace the main beam and adjust the mounting height of the suspension | |
Shock absorber damaged | Replace the main beam and shock absorber | |
Displacement of main beam | The main beam bolts or U-bolts are not fastened | Adjust the main beam and tighten it according to the specified torque |
Bad road conditions | Adjust the main beam, tighten it according to the specified torque and drive slowly |
(Table 5. Troubleshoots of Steel structural parts)
2.5 Troubleshoots of pneumatic circuit
As shown in Table 6 below.
Problems | Causes | Troubleshooting |
Air leakage in pneumatic circuit | Friction and damage between pneumatic circuit and moving parts | Check and reasonably arrange the pneumatic circuit and replace the damaged air hose |
Pipe pneumatic circuit joints are damaged | Replace damaged joints | |
pneumatic circuit folding | Check and reasonably arrange the pneumatic circuit and replace the damaged air hose | |
Insufficient air pressure of airbag | Insufficient air supply pressure | Make the air supply pressure of the tractor reach not less 0.6MPa |
The pressure protection valve is working abnormally | Check and replace the pressure protection valve | |
Load sense valve not working | Check and adjust load sensing valve | |
pneumatic circuit damage and air leakage | Find the air leakage and replace the damaged air hose | |
Slow response of level valve | Insufficient air supply pressure | Check the pressure protection valve and the air supply pressure of the tractor |
The pneumatic circuit blocked or damaged | Check and repair the air circuit system | |
The pneumatic circuit was frozen | Unfreezing and draining air tanks |
(Table 6. Troubleshoots of pneumatic circuit)
3. Vulnerable parts list of air suspension
All rubber parts and non-metallic gaskets in the air suspension system are classified as vulnerable parts, including:
1) Rubber block of shock absorber;
2) Rubber joint of load sensing valve adjusting rod;
3) Rubber bushing of air linker;
4) Wear resistant washer.
4. Tightening torque table for air suspension standard parts
As shown in Table 7 below.
SN | Specifications | Tightening torque（N·M） | Application |
1 | Nut M8 | 80 | Fastening load sensing valves |
2 | Nut M16×1.5 | 350 | Installation of lower brackets of load-carrying airbags |
3 | Nut M20×1.5 | 600 | Installation of shock absorbers |
4 | Nut M22×1.5 | 800 | Fastening U-bolts and torsion beams |
5 | Nut M30×2 | 1100 | Bolt tightening of air linkers |
6 | Nut M12*1.75 | 250 | Fastening airbags and brackets |
(Table 7. Tightening torque table of air suspension standard parts)
Note: the above contents are for reference only, please follow the manufacturer's manual.
Compiled by WONDEE Autoparts
2022-1-25
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