The air suspension on the 4-series offers a range of new features which improve comfort, increase manoeuvrability and reduce air consumption – and thus fuel consumption. Four optional level-control systems enable load-handling to be tailored fo each application. Scania’s suspension is based on a simple, yet refined design featuring one air spring on each side of the axle.
The front axle is held in place by torque rods, an anti-roll bar and a Panhard rod. The two air springs are located between the axle and the chassis.
Rear suspension consists of an air spring on each side. The springs are mounted on an air spring link which keeps the axle in position and provides a degree of longitudinal stability. The axle and air spring links form a roll-resistant unit, with an integrated anti-roll function.
All air suspended vehicles have two riding heights, the top level being used, for instance when extra clearance is needed when using snow-chains. Self-levelling is still operational and the ride height can be adjusted on the move.
Softer air springs
Larger spring units are now introduced, which are about 40% softer than on the 3-series, one reason being their increased air volume. The shock absorbers have been modified to suit the new spring characteristics and moved outwards for increased roll resistance.
The air spring mounting has beeen simplified, making replacement far quicker. The spring rubber can now be replaced separately. The axle attachment to the spring links has also been refined, reinforced and modified to suit new tag-axle and tandembogie designs.
Four level control systems
Operators now have a choice of one mechanical and three electronic level control (ELC) systems:
- Mechanical level control
- ELC basic
- ELC fast
- ELC load handling
Mechanical level control is available on 4×2 tractors and rigids with rear air suspen-
sion only. Lifting is operated by a dashboard-mounted switch.
ELC basic reduces load-handling times by at least 70% for a tractor and semi-trailer
rig, compared with the mechanical system. At the same time, air consumption drops
by up to 85%. The system is available on all air-suspended vehicles and is operated
by a remote control unit.
ELC fast has higher operating pressure and two additional air tanks for faster action.
Times for raising a loaded tractor and semitrailer from driving level to maximum
height are 80% faster than with the mechanical system. The system also improves
the load-transfer response and capacity, which is highly beneficial to improve trac-
tion on icy roads. Operated by remote control.
ELC with load-handling is only available on rigids with full air suspension. This sys-
tem also has a higher operating pressure and additional air tanks – four tanks on
4×2 and six tanks on 6×2 and 6×4. The system contains sufficient air for load han-
dling even with the engine switched off. Operated by remote control.
With ELC it is possible to pre-program two frequently used loading/unloading levels
via the remote control. On vehicles with ELC there is a standby function which main-
tains a preset chassis height for 2 hours after the engine and ignition have been
switched off – a practical feature when the vehicle is stopped for loading or unload-
When loading or unloading is completed, pressing a button in the remote control
returns the truck to its normal ride height.