Brake Master Cylinder: Adjustments

Adjusting the brake pushrod
The brake pedal has no stop. Since, when the brake pushrod is correctly set, the brake pedal has no support possibility in its original position, the permanently set free play in the brake unit is guaranteed. As a result, a pushrod play of approximately 1 mm is noticeable by manual actuation on the pedal plate of the brake pedal.





Adjusting the pushrod length changes the position of the brake pedal. To do this, undo the lock nut and turn the pushrod accordingly at the hexagon (arrow).





The brake pushrod is correctly set if the dimension X is 45 + 5 mm. Perform measurement between the center of the brake pedal plate and the accelerator.

Brake light switch setting
The switch travel of the brake light switch is designed so that the brake light lights up before braking pressure builds up. The switches are self-adjusting and are mounted in a bayonett lock in the pedal block through a 90° turn. By way of its self-adjustment function, the switch compensates for the tolerances in the pedals during initial assembly. However, if the switch is "overpressed" during work on the pedals or on the brake unit, the switch travel or pedal travel up to the switching point is lost.
The consequence: The brake lights are always on or flicker when traveling over bumps. In vehicles with cruise control, the cruise control can be deactivated as a result of vehicle vibrations under certain circumstances.
Therefore, the switches must be readjusted after any work in which the brake pedal is moved out of its "normal" position (for example, work on the pedals or on the brake unit).

Checking stop light switch adjustment (No. 1)





The pedal must be felt to travel approximately 5 to 10 mm before the brake light lights up. At the same time, check (make sure) that the brake light lights up before the pedal meets perceptible resistance or before brake pressure builds up.

Adjusting switch in the event of insufficient pedal travel
There are two possible ways of adjusting the switch if the pedal travel to the operating point is too small.

1st possibility:
- Press brake pedal and pull out plunger of the switch.
- Release pedal. Check adjustment.

2nd possibility:
- Release switch by turning, it 90°, and pull it out of its installation opening.
- Pull switch plunger out of the switch as far as it will go.
- Reinstall switch.
When fitting the switch for the first time, it is important to press vertically against the bearing surface. It will otherwise not be possible to lock the switch (90° turn), even using a lot of force.

Note The switch might not fit in its seat without play after it has been installed and removed several times. As soon as the switch perceptibly .. "wobbles" in its receiver, it must be replaced by a new switch.

Adjusting the switch if the pedal travel is too large
Press the pedal; press the plunger into the switch by one notch (audible click). This decreases the pedal travel to the operating point by approximately 3 ... 4 mm. Then recheck the adjustment.