Brake test on the test bench or test drive - wh4290pkw0000x(4290)
WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.
Model 107 from 8/85; 123; 124, 129, 140 up to 6/93; 126 from 9/85; 201 from 1/85
Check parking brake
VEHICLES WITH 4MATIC
| Service brake or electric change-over switch in engine compartment | switch to position "A" or "Test". |
VEHICLES WITH ASD
| Ignition | switch off, because otherwise rear axle would be locked. |
| Deceleration values for parking brake | measure on brake test bench. If the braking effect of the parking brake is inadequate or unequal, it can be braked in (see 4290/2 "Braking in parking brake according to specifications"). |
TESTING SERVICE BRAKE
| Idle travel at brake pedal | check. It should be possible to press the brake pedal down to approximately one half of the total travel with a force of approx. 200 N. This test must be accomplished with vacuum support. |
| Deceleration values for service brake | measure on brake test bench. |
Braking in parking brake according to specifications
NOTE:
When the parking brake is actuated, the pedal or lever should not catch in the arresting mechanism.
- a) Drive on dry road, initial speed approx. 50 km/h. Apply parking brake 2 to 3 times with force of 100-200 N on pedal or 80-160 N on hand lever and decelerate vehicle to stop.
Pay particular attention to traffic behind, because the stop lamps do not light up.
- b) Drive on dry road at constant speed of approx.
50 km/h. Apply parking brake with force of max.
100 N on foot lever or 80 N on hand lever for 10 seconds.
- c) Operate vehicle on chassis or function dynamometer at constant speed of 50 km/h (3rd gear). Apply parking brake with force of 100 N on foot lever or 80 N on hand lever for 10 seconds (do not exceed specified force).
- d) On brake test stand apply parking brake with constant force of 150-200 N on foot lever or 120-160 N on hand lever for 2 minutes. Observe following: Do not allow parking brake to arrest. During the braking operation the brake disc drum expands due to heat-up reducing the actuating forces.
NOTE:
After the parking brake has cooled off, the braking procedure can be repeated. If the parking brake does not release perfectly after the test or if it pulls to one side after the braking procedure and adjustment (permissible deviation from higher value: 50%), check the brake shoes and control cables, replace, if required.
PARKING BRAKE ADJUSTMENT VALUES
| Model | 107 | 124 129 up to 09/89 |
124 129 as of 10/89 |
126 | 140 | 201 up to 01/87 | 201 as of 02/87 |
|---|---|---|---|---|---|---|---|
| Number of notches at which parking brake must be readjusted if sufficient braking effect has not been reached up to that point. | 2 | 4 | 5 | 4 | 5 | 2 | 3 |
If the specified test values are not reached, re-adjust parking brake (RI 42-540).
NOTE:
When checking the service and parking brakes observe the minimum deceleration as well as permissible deviations specified by law. The German motor vehicle regulations prescribe the following minimum deceleration ratio:
Service brake 40 %
Parking brake 20 %
This deceleration ratio is the ratio of the total braking force at the wheels to the total vehicle weight.
In addition the following deviations from the greater value are permissible on dynamometers:
Service brake 25 %
Parking brake 50 %
In all other countries observe existing regulations.