Front Suspension Specifications (BMW 5 Series E12)

The front suspension is independent, of the "swinging candle" type, with hydraulic shock absorber struts installed at an angle to the rear of the car, with helical, uncentered cylindrical springs, lower wishbones with stretchers and an anti-roll bar.

The telescopic strut is equipped with a coil spring, a rubber compression buffer and the upper support of the strut. The upper support is attached to the mudguard strut of the body. The telescopic strut rests on the ball joint of the suspension arm.

The anti-roll bar is a rod whose knees are connected to the suspension transverse arms via rods with rubber-metal hinges. The middle part of the rod is attached to the front suspension cross member with brackets with rubber pads.



Wheel travel, mm:

• up: 94;
• down: 106.

Front suspension spring characteristics

* Since the 1980 model year, front suspension springs without markings or with a red index were used.

Shock absorbers

Double-acting hydraulic telescopic shock absorbers.

Shock absorber characteristics

On some cars with reinforced suspension, instead of Vode shock absorbers, Bilstein shock absorbers with different characteristics were installed. In this case, stiffer suspension springs were used.

Since the 1977 model year, the characteristics of the Boge brand shock absorbers installed on the 525 and 528 models were changed.

Catalog number: 1 112 018 2.

Letter index: "L".

Shock absorber length, mm:

• with extended stem: 625.5;
• with piston rod retracted: 448.5.

Since the 1980 model year, the following Boge shock absorbers have been installed.

Shock absorber characteristics

Beginning with the 1982 model year, some of the front suspension shock absorber specifications were changed.



Volume of oil between the strut housing and the shock absorber cylinder, cm³: 30-35.

All models of cars were equipped with Boge shock absorbers. Marking "n" on the upper support mounting nut. Catalogue number of the shock absorber: 1 124 294.

Suspension arms

Brand of the ball joint of the control arm: Lemforder or Ehrenreich.

Ball pin overturning moment, kgf·m:

• lemforder margin hinges: 0.50-0.70;
• ehrenreich brand hinges: 0.15-0.50.

Maximum clearance along the height of the ball pin, mm: 1.4.

Anti-roll bar

Anti-roll bar diameter, mm:

• "518", "520": 21;
• "520" with automatic transmission, "520i": 22;
• "525", "528": 23.

From model year 1982, stabilizer bar diameter for BMW "518", "520i", "525i" wounded 16 mm. for "528i" - 17 mm.

Front axle

Front wheel alignment angles

Toe-in*, mm: 1.5⁺¹_-0,5

Camber*, mm: 0°30'±30' (for reference).

Pivot axis tilt angle (for reference):

• longitudinal: 7°40'±30';
• transverse: 8°30'±30'.

Permissible difference in longitudinal angles of inclination of wheel turning axes, no more than: 0°30'.

Maximum wheel turning angle:

• internal: 43°;
• external: 34°.

Difference in wheel turning angles when turning:

• inner wheel: 20°;
• outer wheel: 18°30'.

* For a vehicle with a full fuel tank under a load distributed as 68 kgf on the front seats plus 68 kgf on the rear seat plus 25 kgf of cargo in the left part of the luggage compartment.

Since the 1978 model year, front wheel alignment angles for models "525", "528" and "528i" have the following meanings:

• camber: 0°±30';
• transverse angle of inclination of the pivot axis: 8°±30'.

Maximum turning angle of the inner wheel: 44°.



Since the 1980 model year, the front wheel toe-in is 0°19'±5' or 2.0±0.6 mm.

Since model year 1982, for all models, the difference in the angle of rotation of the wheels on a bend at an angle of rotation of the inner wheel of 20° is -1°50', camber of the front wheels: -0°20'±30'; longitudinal angle of inclination of the axis of rotation: 8°20'±30'; transverse angle of the pivot axis: 12°±30'.

Front wheel hubs

The wheel hub rotates in two tapered roller bearings.

Axial clearance of bearings, mm: 0.02-0.06 (since 1980 model year: 0-0.05 mm).
Amount of grease (type Shell Darina, dropping point: 260°C) added, g:

• in bearings: 50;
• in the hub cap: 20.

Tightening torques of main threaded connections, kgf·m

• Nut for fastening the telescopic stand to the lower support: 7.2-8.0 (7.8-8.6)*.
• Nut for fastening the upper support of the telescopic strut to the body: 2.2-2.5 (2.2-2.4)*.
• Steering rod ball joint fastening nut to steering knuckle: 8.1-9.0.
• Nut and lock nut for fastening the stabilizer connecting rod to the suspension arm: 6.0-7.0.
• Suspension arm bolt nut: 8.1-9.0**.
• Stretch mounting nuts: 7.0-9.0**.
• Strut housing nut: 12.0-14.0 (14.0)*.
• Bolt for fastening the front suspension cross member to the side member: 7.3-8.0.
• Anti-roll bar mounting bolt nuts: 4.4-4.8.

* Since model year 1982.
** For vehicle under load, see "Front Wheel Alignment Angles".

The original source of the article is on the website: BMWman.ru