Parking Brake

Parking brake




The parking brake applies the brake pads directly against the rear discs. There is no internal drum. Therefore the rear brake calipers have an integrated parking brake mechanism.
The mechanism adjusts itself after every time the brake is used.
The parking brake cable's horizontal movement is converted to a rotating movement at the input shaft (1). At the end of the shaft there is a plate (2) with three tapered recesses (3). There is a ball bearing in each recess. Together with the sealing plate (4) this unit forms a bearing with 3 balls, which means that the shaft (1) is displaced axially when it is turned. To start with, the axial displacement is big in relation to the rotation and then gets smaller in relation to the rotation. This results in an increase of the application force.
When the parking brake is applied, the shaft (1) is rotated and displaced axially. This means that the setting shaft (5) moves against a spring pressure (6). This shaft absorbs the movement via the nut (7) for the wheel brake's piston (8).
This forces the piston against the brake pad. Thanks to the floating brake caliper, the brake disc is locked by both brake pads.
The setting shaft (6) has threads with high pitch which means that the nut (8) is threaded up. In this way, a new setting is made every time the brake is applied.
After a brake application, the seal ring (9) will force back the piston slightly. The piston can perform this movement since there is a small play in the screw's thread.
When changing brake pads, the setting shaft must be turned back by rotating the brake piston with the special tool.

Adjusting parking brake cable
The parking brake's cable is adjusted by the parking brake lever. The adjusting nut (10) is accessed from inside the passenger compartment. The balancing yoke (11) is needed to distribute the brake force evenly to both rear wheels. You can also access this from inside the passenger compartment.