34 00... Testing AWD vehicles on dynamic brake and power analyzers (E70, E71)

NOTE: Running AWD vehicles on dynamic brake analyzers is governed by different instructions, depending on the vehicle model.

IMPORTANT: Power measurements on single-axle roller dynamometers are generally not permitted as total failure of the transfer case can not be ruled out during such measurements.

In order to test AWD vehicles on dynamic brake analyzers, it is essential to follow various measures in accordance with the special instructions.

1. Checking service brake:

IMPORTANT:

Before driving onto the brake test stand (dynamic brake analyzer), switch off the Hill Descent Control (HDC) and keep it switched off while testing the brakes.

The HDC indicator lamp must not light up!

It is possible for the HDC indicator lamp to go out or not to light up even when HDC operation is activated. This may be because HDC is temporarily unavailable due to high brake temperature.

Carry out brake testing with selector lever in N position (Neutral) only.

Selecting a gear causes the transfer case clutch to close when the analyzer rollers start up. Consequently the stationary axle is also driven, and the vehicle surges from the analyzer. Because the front and rear axles are now coupled, the axle to be tested then increases the brake force until the analyzer is shut down.

2. Checking parking brake:

IMPORTANT: The test may only be carried out with the engine switched off, the selector lever in the "N" position and the ignition switched on.

The electromechanical parking brake can not be tested on a plate test stand.