Complete suspension - general - GF32.00-P-9611-01J
Models 215, 220 with code 487a Active Body Control (ABC)
General
Models 215.375/378 and model 220.178 are fitted with Active Body Control (ABC) as standard. ABC is also available as special equipment for all series 220 models (except Model 220.026). As in the case of AIRmatic, hydraulic Active Body Control (ABC) is a fully-supporting suspension system with a vehicle level independent of load. The advantages are a high level of suspension/ride comfort, low level of pitching motion when starting off and braking. Rolling motions due to alternating excitation are reduced significantly even without a torsion bar at the front and rear axle.
The hydraulic components are:
- Oil reservoir with oil dipstick and return flow filter.
- Radial piston pump with intake restrictor.
- Front and rear spring struts with connection for oil pressure line and connector for movement sensor
.
Included in the spring strut are steel springs, spring adjustment and twin-tube shock absorbers. The spring strut fixing corresponds to models 220 with AIRmatic.
- The damper adjustment valve I (HPS) and the front axle pressure reservoir is located at the bottom left of the longitudinal member.
- The pressure supply valve unit is located at the bottom right of the front axle carrier. The pulsation damper is screwed into the valve unit.
- The damper adjustment valve II (HPS) and the return flow pressure reservoir is attached to the left of the vehicle floor in front of the rear axle.
- The rear axle pressure reservoir is secured on the rear right of the underbody.
- The oil cooler is located upstream of the condensor/air conditioning.
- The bleed screws for draining the hydraulic fluid for repair work are attached in the pressure line to the spring strut.
The vehicle level is recorded at the control arm at the front axle and at the spring link at the rear axle and conveyed to the control module. The level at the individual spring struts is controlled by four control valves in the adjustment valves. The pressure oil is supplied by the radial piston pump via the adjustment valves in the individual spring struts.
Also refer to detailed function description of Active Body Control (ABC).
Notes on repair
The filling quantities of the ABC system are approx. 4.0 liters when refilling.
The oil reservoir (2) for the ABC system must only be filled with special hydraulic fluid in accordance with "Sheet 345.0 of MB Specifications for Service Products" (part no. A 001 989 24 03). The oil reservoir (2) for the power steering pump is located separately but is filled with the same special hydraulic fluid.
- When working on the ABC system the area of the oil pressure line connections of the components to be removed should be cleaned before starting the repair and machining residues, e.g. shavings and fluff must not enter the system.
- Drain hydraulic fluid via the particular bleed screw and dispose of the fluid.
- Pay great attention to cleanliness when filling as the smallest dirt particles can result in the failure of Active Body Control.
- When bleeding with the engine running always ensure that there is sufficient hydraulic fluid in the oil reservoir and that the radial piston pump does not draw any air into the system.
- To bleed the ABC system, operate the level switch several times with the engine running, with the vehicle raised and lowered. This means that any air can escape from the system.