Air suspension on trailers not only ensures gentler treatment of the load being hauled but also less wear and tear on the roads. This aspect is of growing importance as traffic volume becomes increasing dense.
As a rule, each axle has two air springs. In multi-axle combinations, one axle is frequently provided with an axle-lifting device to protect the tires on empty runs or when the vehicle is only partially loaded.
Usually, convoluted air springs are used for raising and lowering lift axles

Bus

In buses, air springs deliver safety and ride comfort. Thanks to the self-leveling system, the vehicle remains at the same level, which means that the boarding level also remains unchanged, regardless of the number of passengers.
With additional control functions, the vehicle body can “kneel”, which aids entry and alighting.
This generally entails fitting two air springs to the front axle and trailing axle and four on the rear or drive axles.

Product Photos

Maintenance of the air springs, Vehicle Check-List

Check the air lines and devices of leakage and that they turns freely.
Check the bellows bearing for damage, correct fastening, deformation, sharp edges.
Check the shock absorbers for operation and impermeability as well as tightness and bearing.
Periodically, check nuts and bolts for proper torque. For specific recommendations see manufacturer's manual.
Check axle suspension, trailing arms and rods for wear.
Check height control valve to see that it is functioning properly. A properly maintained valve will save unneeded maintenance expense.
Routine inspection of all of the above according to manufacturer's instructions, will extend the life of your vehicle and reduce your overall maintenance expense.

Air Spring Installation

Before you start installing air springs, make sure you have all the necessary tools and equipment to perform the repair safely.
Familiarize yourself with the suspension on which you are performing the repair by reviewing the manufacturers service guide.
If you are in doubt about something, ask for assistance from a qualified suspension specialist, the suspension manufacturer or the air spring manufacturer; This can save you a lot of time and aggravation later in the job.

Important tips to remember when installing a new unit

Check levelling valve, linkage and transmission parts for wear and damage and if necessary replace the damaged parts.

Check that the shock absorber for leakages and take a shock absorber test. A defective shock absorber must be replaced.

Once the air lines are disconnected, check their entire length for cracks or other damage. Replace worn parts.

With the air spring removed, other parts of the air suspension become more accessible. Check for wear or damage of the frame hangers, trailing arm bushings, torque rods, the trailing arms and the air spring mounts. When it is necessary, also replace parts.

Check bearing for air spring bellow for external damage, deformation, sharp edges and correct fastening.

Before installing the new unit, clean the air spring mounting plates to ensure proper attachment to the suspension.

Always use new attaching bolts for the installation and observe the tightening torques. Never use old bolts, because these can fall out.

Check the linkage of the levelling valve to see that it is functioning properly. Under load, the linkage should move from the neutral position up to the intake position. This lets air into the springs, which brings the arm back to the neutral position. This lets air into the springs, which brings the arm back to the neutral position. That opens the exhaust valve, allowing air to escape until the arm returns to the neutral position. Then check the driving level.

IATF16949 Truck Trailer Seat Air Spring Rubber Air Bellow W02-358-7075