Rear suspension elements (4 x 4 powertrain)
1 – rear suspension cross member, 2 – body mount support, 3 – metal-rubber element, 4 – suspension buffer, 5 – suspension arm, 6 – hub base, 7 – hub, 8 – axle shaft nut, 9 – bearing, 10 – mounting ring, 11 – control tailpiece, 12 – casing, 13 – cylinder, 14 – branch, 15 – reservoir
Checking the height h of the rear suspension
Peugeot 405 vehicles with four-wheel drive (4 x 4) are equipped with hydropneumatic rear suspension, which maintains a constant rear body height regardless of the vehicle load.
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, acts as a shock absorber. Instead of acting on a coil spring, the suspension arm acts on a piston, which converts this action into wheel movement. Maintaining the main pressure is a prerequisite for ensuring the normal suspension height. This pressure is created by an electrically driven hydraulic pump. The required pressure is determined by a switch whose action depends on the height of the body.
Regardless of the load on the vehicle, the height of the body remains constant.
The rear suspension has two special levers mounted on conical bearings, the tightness of which is ensured by sealing rings. Each of the levers has a round hole on the side of the drive axle hub. Each lever also has a socket for the ball joint of the intermediate tailpiece, transmitting movement to the suspension cylinder.
Each of the two suspension cylinders has a piston and an element connecting it to the suspension arm, a sealing and leak detection housing, a connection to the shock absorber element and a branch supplying fluid to the reservoir.
The reservoir is adjusted to a pressure of 4.0 MPa and has four connections: to two suspension cylinders, to a high-pressure hydraulic pump and to a pressure regulator.
The hydraulic pump is activated by a body height sensor connected to the stabilizer via connectors.
[Source available on the website: PEUGEOTBOOK]
Electrically controlled drain valve opens the liquid outlet in case of too high pressure (reduced load on the trunk, reduced load on the rear suspension).
The hydraulic fluid reservoir supplies the circuit. It receives excess fluid and fluid when the drain valve is opened. From this reservoir, the fluid is supplied to the high-pressure pump through a filter.
The pressure regulator matches the braking force to the load on the rear axle (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 crossmember 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.