Test brake system with pressure tester for leaks

AR42.10-S-0015E

Test brake system with pressure tester for leaks

27.01.2020

Model

447, 448

2

Pressure tester

 Danger

Risk of death caused by vehicle slipping or toppling off of the lifting platform.

Align vehicle between vehicle lift columns and position the four support plates at the vehicle lift support points specified by the vehicle manufacturer.

AS00.00-Z-0010-01A

 Danger

Risk of death when working on component parts and systems with U >= 30 V alternating voltage (AC) or U >= 60 V direct voltage (DC)

Do not touch damaged or defective live component parts and lines or non-insulated electrical connections and lines.

AS00.00-Z-0035-01A

 Caution

Risk of poisoning from swallowing brake fluid. Risk of injury from skin and eye contact with brake fluid

Only pour brake fluid into suitable and appropriately marked containers. Wear protective clothing and eye protection when handling brake fluid.

AS42.50-Z-0001-01A

Topical note

General information on vehicles with high-voltage on-board electrical system and/or lithium-ion battery and/or gaseous-fuel drive system as well as personal protective equipment

AH00.00-Z-0300-01A

Topical note

Notes on externally invisible brake fluid loss

AH42.10-P-9406-02A

Topical note

Notes on repairs to brake system

AH42.00-P-0003-01A

Topical note

Brake fluid notes

AH42.50-P-0001-01A



Check

1

Lift vehicle with vehicle lift.

AR00.60-S-1000E

2

Unscrew bleed valve of one brake caliper.

3

Attach pressure tester (2) to brake caliper using connection fitting.



000 588 07 21 00 Test equipment

WS42.00-P-0014B


Do not use a pressure tester (2) for hydraulic fluid.
The brake fluid can otherwise be mixed with hydraulic fluid, which can cause brake failure.

4

Lower vehicle.

5

Bleed pressure tester (2).

 See manufacturer's operating instructions.

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

6.1

Run engine at moderate engine speed, generate as high a vacuum as possible in the brake booster by suddenly releasing the accelerator pedal and switch off engine.

Model 447 with engine 274, 622, 651, 654
Model 448

6.2

Actuate electric vacuum pump for approx. 30 s using diagnostic device.

Model 447 with engine 780.701/702



AD00.00-S-2000-04E

7

Install brake pedal jack with adapter between brake pedal and driver's seat.

 Make sure that the special tools are seated correctly.

 Brake pedal jack

*000589183100

 Adapter for brake pedal winch

*211589003100

8

Depress brake pedal with brake pedal jack as far as possible and note pressure drop.

 During the test duration of 5  min, the pressure drop may not be more than 5  % of the value displayed at the start.

9

Remove brake pedal jack with adapter.

10

Reduce vacuum in brake booster by depressing brake pedal several times.

11

Install brake pedal jack with adapter between brake pedal and driver's seat.

 Make sure that the special tools are seated correctly.

 Brake pedal jack

*000589183100

 Adapter for brake pedal winch

*211589003100

12

Reset brake pedal jack until test pressure of 3 bar is shown on pressure gauge.

 During the test duration of 2 min, the line pressure must not drop off.

13

Remove brake pedal jack with adapter.

14

Raise vehicle.

15

Detach pressure tester (2) with connection fitting from brake caliper.



000 588 07 21 00 Test equipment

WS42.00-P-0014B

16

Screw in bleed valve on brake caliper.

 Bleed valve at front axle floating brake caliper

*BA42.10-N-1001-03B

 Vent valve on rear axle floating caliper

*BA42.10-N-1001-12J

17

Bleed brake system.

AR42.10-S-0010E

 After the test, only bleed the brake caliper to which the pressure tester (2) was connected.

 Front axle floating caliper

Number

Designation

Model 447, 448

BA42.10-N-1001-03B

Bleed valve at front axle floating brake caliper

Nm

14

 Rear axle brake caliper

Number

Designation

Model 447, 448

BA42.10-N-1001-12J

Vent valve on rear axle floating caliper

Nm

14