Rear suspension elements (power unit 4 x 4)
1 - rear suspension cross member, 2 - body mounting support, 3 - metal-rubber element, 4 - suspension buffer, 5 - suspension arm, 6 - hub base, 7 - hub, 8 - axle shaft nut, 9 - bearing, 10 - adjusting ring, 11 - control shank, 12 - casing, 13 - cylinder, 14 - branching, 15 - tank
Checking the height h of the rear suspension
Peugeot 405 vehicles with four-wheel drive (4 x 4) are equipped with a hydropneumatic rear suspension, which maintains a constant height of the rear part of the body, regardless of the load on the car.
A special tank filled with nitrogen is exposed to the suspension elements via a hydraulic circuit. The gas acts in this case as a spring, and the oil, throttled in calibrated pipelines, plays the role of a shock absorber. Instead of acting on a coil spring, the suspension arm acts on a piston, which converts that force into wheel movement. Maintaining the main pressure is a prerequisite for maintaining a normal suspension height. This pressure is generated by an electrically driven hydraulic pump. The required pressure is determined by a switch, the action of which depends on the height of the body.
Regardless of the load on the car, the height of the body is constant.
The rear suspension has two special levers mounted on tapered bearings, the tightness of which is ensured by sealing rings. Each of the levers has a round hole on the side of the drive shaft hub. Also, each arm has a seat for the ball joint of the intermediate shaft, which transmits movement to the suspension cylinder.
Each of the two suspension cylinders has a piston and an element that connects it to the suspension arm, a sealing and drip detection casing, a connection to a damping element and a branch that supplies fluid to the reservoir.
The tank is adjusted to a pressure of 4.0 MPa and has four connections: with two suspension cylinders, with a high pressure hydraulic pump and with a pressure regulator.
The hydraulic pump is activated by a body height sensor connected to the stabilizer using connectors.
An electrically controlled drain valve opens the liquid outlet in case of too high pressure (less load on the trunk, less load on the rear suspension).
The hydraulic fluid reservoir provides power to the circuit. It receives excess liquid and liquid when the drain valve is opened. From this tank, liquid is fed to the high pressure pump through a filter.
Pressure regulator matches braking force to rear axle load (depending on the pressure in the circuit).
A special switch attached to the tank holder limits the pressure to a maximum value of 13.5 MPa.
The rear suspension cross member carries all the elements, as well as the drive axle. It is attached to the body at the front with two elastic supports, and at the rear with two metal-rubber elements.