Notes On Brake Test Stand Run - AH42.00-P-4292-01A
MODEL ALL (4xWD, BUS, CAR, smart)
Check as per EU guideline 2010/48/EU for vehicles with initial registration as of 28.07.2010 (in Germany, for check and evaluation of service brake, for preparation and execution of the main inspection, 29 German vehicle licensing regulations)
The guideline for main inspection of brakes of 24.05.2012 "Evaluation of brakes on brake test stand" has been changed in the course of the implementation of the EU guideline 2010/48/EU into national law. The change refers to the check and evaluation of the service brake for preparation and execution of the main inspection 29 StVZO. The check and evaluation of the parking brake does not change.
The VDA brake test procedure approved for vehicles with initial registration as of 28.07.2010 using the pedal force meter is discontinued at the testing organizations at the moment. The testing organizations develop and test their own brake test procedure. From the manufacturers' point of view, the practical application of the VDA brake test procedure and the procurement of the required measuring instruments only makes sense and is only necessary when the test procedure of the technical inspection associations is complete.
The previous brake test procedure for vehicles with initial registration up to 27.07.2010 will continue to be carried out until the final implementation of the guideline for main inspection of brakes by the technical inspection association.
Further implementation of the new guideline for main inspection of brakes will be communicated in due time.
General legal and manufacturer's specifications
- Test conditions
Vehicle is in an unladen condition. The tires must be adapted to the weather conditions. On vehicles without vacuum pump, a short throttle blip is required before every brake application in order to ensure a sufficient level of vacuum in the brake booster.
- Conditioning
Conditioning of the brake system takes place in a short test drive or on the roller dynamometer.
- Vehicles with initial registration up to 27.07.2010
Assessment of total braking ratio and deviation in brake forces at front axle (FA) and rear axle (RA)
This procedure may only be used on vehicles with initial registration up to 27.07.2010.
Computation of total braking ratio at service brake
Brake force VR [daN] + Brake force VL [daN] + Brake force HR [daN] + Brake force HL [daN]/Permissible gross mass [kg] x 100 = Total braking ratio as a %
The total braking ratio must be over 50 %.
Computation of total braking ratio at parking brake
Brake force HR [daN] + Brake force HL [daN]/Permissible gross mass [kg] x 100 = Total braking ratio as %
Vehicles with initial registration up to 27.07.2010:
The total braking ratio must be over 16 %.
Computation of deviation in brake forces between driver and passenger sides
Difference in brake forces at an axle [daN]/largest brake force of the axle [daN] x 100 = deviation in %
Service brakes
The service brake must act on both axles and on both sides of each axle. The difference in brake forces at the wheels at an axle must not be more than 25 % with regard to the given higher measurement value.
Parking brake
Vehicles on which the parking brake can be actuated while driving:
The parking brake must act on both sides of an axle and the difference in the brake forces must not be more than 50 % with regard to the given higher measurement value.
Vehicles on which the parking brake can only be actuated when the vehicle is stationary:
The parking brake must act on both sides of an axle and the difference in the brake forces must not be more than 95 % with regard to the given higher measurement value.
- Vehicles with initial registration as of 28.07.2010
Reference brake force procedure
For evaluation of the brake system, the control force of the brake pedal and the brake force distribution must also be evaluated apart from the deviation in brake forces at an axle.
This new approach applies to vehicles with registration as of 28.07.2010 and must strictly be applied as of 01.01.2013.
The following factors are assessed:
- Brake force shares at front axle (FA) and rear axle (RA)
- The required proof load (pedal force) for a total braking ratio of 58 %
- Deviation in brake forces at an axle
Test conditions:
- Pedal force meter mounted at brake pedal
- Measurement of brake forces at front axle and rear axle carried out with specified pedal force.
Computation of increase in brake force at FA
Brake force FR [daN] + brake force FL [daN]/proof load FA [N] = increase brake force FA
Computation of increase in brake force at RA
Brake force RR [daN] + brake force RL [daN]/proof load RA [N] = increase brake force RA
Computation of total increase in brake force
Increase in brake force FA + increase in brake force RA = Total increase in brake force
Computation of brake force share at FA
Increase in brake force FA/Total increase in brake force = Brake force fraction FA in % (FA min.)
Computation of brake force share at RA
Increase in brake force RA/Total increase in brake force = Brake force fraction RA in % (RA min.)
Computation of pedal force for 58 % braking ratio
0.58 x Permissible gross mass [kg]/Total increase in brake force = Max. Pedal force [N] for 58 % braking ratio
Computation of deviation in brake forces between driver and passenger sides
Difference in brake forces at an axle [daN]/largest brake force of the axle [daN] x 100 = deviation in %
Service brakes
The service brake must act on both axles and on both sides of each axle. The difference in brake forces at the wheels at an axle must not be more than 25 % with regard to the given higher measurement value.
Parking brake
Vehicles on which the parking brake can be actuated while driving:
The parking brake must act on both sides of an axle and the difference in the brake forces must not be more than 50 % with regard to the given higher measurement value.
Vehicles on which the parking brake can only be actuated when the vehicle is stationary:
The parking brake must act on both sides of an axle and the difference in the brake forces must not be more than 95 % with regard to the given higher measurement value.