Installation survey of brakes - general - GF42.10-P-9611-01I
General
The brake system of the hydraulic dual-circuit brake system and split of the two circuits on the front and rear axle corresponds in principle to the previous design.
The brake performance has been further improved by the reduced vehicle weight and the larger brake disk measurement. Electronic brake force distribution is an integral part of the ESP driving dynamics control system.
Fixed caliper and disc brake
All models have a 4-piston fixed caliper on each side of the front axle. To achieve a significant reduction in weight, a combined construction was chosen, with the material of the piston housing (2a) made from aluminum and the stators (2b) made from spherulitic graphite iron. An aluminum 2-piston fixed caliper is installed on the rear axle. The bolted-type fixed caliper cannot be repaired.
The size of the brake splash shields on the front axle has been reduced to improve brake cooling. To ensure brake performance and to optimize the response characteristics, primarily in the wet, the front brake disks (1) are internally-ventilated and perforated.
Foot-operated parking brake
The design and method of operation of the foot-operated parking brake with automatic slack adjuster is virtually identical to that on models 140.
| Designation | 220.063/065/165 | 220.070/075/170/175 | ||
|---|---|---|---|---|
| Brake pads | Width mm | Front | 120 | 120 |
| Rear | 62 | 62 | ||
| Thickness mm | Front | 17 | 17 | |
| Rear | 15.5 | 15.5 | ||
| Brake calipers | Version | Front | 4-piston fixed caliper | 4-piston fixed caliper |
| Rear | Fixed caliper | Fixed caliper | ||
| Piston dia. mm | Front | 40/44 | 40/44 | |
| Rear | 42 | 42 | ||
| Brake discs | Version | Front | Internally-ventilated and | Internally-ventilated and |
| Rear | perforated | perforated | ||
| Discs dia. mm | Front | Solid | Internally-ventilated | |
| Rear | 312 | 330 | ||
| Thickness mm | Front | 300 | 300 | |
| Rear | 28 | 32 | ||
| 11 | 22 | |||
| Brake booster | Diaphragm dia." | 8/9" | 8/9" | |
Brake booster
There is still only one unit brake booster with brake assist function in the 8/9" tandem version made from aluminum. Essentially the installed length has been drastically reduced by a specially developed master brake cylinder design. The brake booster has been further developed in terms of the BAS function (Brake Assist). With the brake assist function it has an integrated solenoid valve which is designed as a proportional solenoid valve as part of. the further development. As a result any brake pressures in the master brake cylinder can be produced by electrical actuation as required and consequently generated at the wheel brake. This additional function is used to assist or control chassis control systems such as ESP and Distronic.
Master brake cylinder
Like all previous master brake cylinders, the new aluminum master brake cylinder (1) is designed as a dual circuit with two brake circuits in series. As usual the pressure force is introduced by the thrust rod of the booster via a spherical cap in the primary piston (1a) which converts the force into brake pressure.
The pressure is built up in the primary and secondary circuit virtually at the same time due to the preload of the springs (1b and 1c) located between the two pistons (1a and 1f).
As a result an even response of the pressure circuit (1d) and float circuit (1e) is achieved. The pressure circuits are sealed via rubber components (1g, 1i, 1h) rigidly installed in the housing. Both pistons (primary and secondary) are guided by guide rings (1j, 1l) rigidly located in the housing. The master brake cylinder springs (1b, 1c) are partially integrated in the pistons (plunger construction). The master brake cylinder cannot be repaired.