Why disk brakes in a truck or bus that travels in excess of 65 mph?

    Improved road handling, higher engine ratings and torque, reduced drag and rolling resistance resulting in faster
    acceleration and higher average speeds

    Higher vehicle speeds with full loads

    Higher traffic density, greater chances of emergency braking

    Extremely high kinetic energy needed to brake on wet roads, high front axle loads effecting vehicle directional stability

    The power and behavior of drum brakes cannot be improved

    Disk brakes provide optimum braking while retaining directional stability

    Flat brake disk (axial brake) under high pressure versus round brake drum (radial brake) during braking

    Full friction surface of the brake pad on the plane brake disk

    No loss of brake power due to overheating or partial contact from brake drum parts expansion

    Higher residual brake force after repeating braking

    Brake disks can withstand extremely high temperatures

    Full contact of brake pads achieve maximum effect

    No vitrification of brake pads. Dangerous fading or slipping is almost completely eleminated

    Disk brakes can withstand higher loads and its efficiency is maintained considerably longer even under the highest stresses

    Disk brake axial arrangement permits a simple and compact design

    Linear characteristics lead to an even progression of brake force

    Basic design principle makes for higher efficiency

    Low hysteresis is particulary suitable to ABS control cycles

    Sensitive brake brake application and better brake feeling

    Uniform braking from small fluctuations in brake forces

    Retardation values retained even under heavy stresses

    Minimal "pulling to one side" due to uneven brake forces

    Driver friendly braking behavior. Sensitive braking in all situations and better braking feeling.

    Optimized installation space in the wheel rim resulting in the largest possible brake disks and pads

    Optimized cooling resulting from open sliding caliper design with internally ventilated brake discs

    Even and safe brake pad wear resulting from simple pad guide with level braking faces

    Long service life of disks and pads versus drum brakes

    Shorter service downtime due to quick pad changes

    Good access for visual brake components checks

    Maintenance free brake components

    Clear economic benefits due to long service life and reduced maintenance downtime

    Minimal braking effect from high temperatures and extreme driving requirements

    Minimal heat fading

    No brake disk distortion from extreme heat due to internal ventilation

    High power and safety reserves for emergencies

    Constant braking power under high stresses

    Shortened braking distance under emergency braking with considerably improved directional stability

    The decisive safety aspects of the disk brake design are shorter braking distances with directional stability and large power reserve under high stress

    The individual components are subjected to extensive test on the test bed. The optimum
    arrangement of components on the axle beam, operational reliability and convincing
    performance are requirements that must be met prior series production.

    The brake disks are subjected to the highest stresses from contact pressure. The broad
    brake disks with radial cavities made of heat resistant special gray cast iron, are still
    operational in temperatures in excess of 1380 degrees F

    Brake performance is tested on the test track and in racing to ensure their practice. Only after
    these extensive tests can the disk brake be cleared for production

    Today, all MAN city, inter-city buses and coaches utilize the MAN disk brake system on all
    wheels with ABS. The disk brake system is used with and without retarders.

    MAN trucks and buses are equipped with air actuated sliding caliper disk brakes

    The high contact forces are transmitted mechanically via needle mounted actuating device

    Depending on size the actuating pressure is transmitted
    evenly to the brake pads via one or two plungers

    The easy action, fully sealed guides between the axially
    moving sliding caliper and fixed brake anchor plate are
    maintenance free

    Integrated automatic adjustment with wear display

    There are no brake shafts, external levers or cylinder brackets, as the brake cylinders are directly attached

    Disk Brakes in detail...

    The high efficiency of 95% is achieved by only a few moving parts and low friction bearings

    Asbestos free brake pads 19 to 23 mm thick, depending on version

    Extremely heat resistant brake disks (34 to 45 mm)made of special gray cast iron with internal ventilation

    The brake disks are 330 to 432 mm in diameter and permissible wear of 6 to 10 mm allowed, depending on version

    The service and parking brakes use the same actuating unit and differ only in the shape of the brake cylinder

    Disk Brakes in practice...

    All friction brakes (drum and disk) have wear parts and are unsuitable for continuous braking, i.e. on long downhill runs

    Disk brakes are no substitue for an engine brake or retarder. Economic driving with sensible use of the engine brake
    or retarder optimizes the service life of pads and disks that are equal to those in comparable drum brakes

    NOW IT IS UP TO THE DRIVER!

    Economic use of technology means driving and braking with anticipation and economic thinking. Disk brakes offers safety in any situation.


    Basically, MAN trucks and buses equipped with disk brakes are maintenance free

    The disk brakes automatically cleans itself by wiping off the effects from disk brake pad residues and outside dirt

    Removable components during disk brake pad replacement:

    » Safety clip
    » Pressure plate with tension clip
    » Disk brake pads with tension clip

    The small amount of removable parts makes it possible for quick replacement of disk pads with litte effort, no special tools or devices

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