DAF CF65, CF75, CF85 Series . Manual - part 904

©

 200423

2-1

Inspection and adjustment

BRAKE SYSTEM AND COMPONENTS

ΧΦ65/75/85 series

6

5

2. INSPECTION AND ADJUSTMENT

2.1 INSPECTION, COMPRESSOR CAPACITY

1.

Bring the engine up to operating 
temperature.

2.

For a vehicle with air suspension, 
the chassis should be at the normal driving 
height.

3.

Put chocks in front of and behind the 
rear-axle wheels to prevent the vehicle from 
moving.

4.

Position the parking brake in the driving 
position.

Note:
If, when draining the air reservoirs, 
they appear to hold an excessive quantity 
of oil, check the condition of the compressor 
and check the compressor for the presence 
of carbon deposits in the compressor pipes.

5.

Bleed the entire brake system.

6.

The capacity test requires that a completely 
empty system should be at operating 
pressure within 5 minutes, at an engine 
speed of 0.6 x maximum engine speed.

BRAKE SYSTEM AND COMPONENTS

2-2

©

 200423

Inspection and adjustment

5

ΧΦ65/75/85 series

6

2.2 INSPECTING THE COMPRESSOR LINE

Remain at a safe distance from 
rotating and/or moving components.

Note:
If excessive values are measured, the inside of 
the air-dryer housing and the silencer on the 
bleed vent should first be cleaned. Then repeat 
the inspection.

1.

Bring the engine up to operating 
temperature.

2.

Bleed the system to a pressure below the 
cut-in pressure of the pressure regulator.

3.

Remove the compressor control pipe (1) 
which is connected to connection point (23) 
of the air dryer. Then seal the opening at 
connection point (23).

4.

Build up pressure in the brake system 
(pressure regulator must cut out).

5.

When the engine is not running, remove the 
safety valve from the compressor pipe and 
replace it with a test nipple.

6.

Connect a pressure gauge (measuring range 
0 - 16 bar) to the test nipple.

7.

Start the engine and run it at maximum 
engine speed.

8.

The pressure gauge should indicate a 
pressure below 2 bar with the pressure 
regulator switched off. If the measured 
pressure exceeds the value indicated, 
the compressor line should be cleaned or 
replaced.

Note:
If the pressure measured is too high, 
this indicates that there are excessive 
carbon deposits in the compressor pipe. 
The cause could be poor condition of the 
compressor (oil consumption).

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R600521

1

R600249

©

 200423

2-3

Inspection and adjustment

BRAKE SYSTEM AND COMPONENTS

ΧΦ65/75/85 series

6

5

9.

Run the engine at idling speed.

10. Bleed the brake system until the cut-in 

pressure of the pressure regulator has been 
reached and switch off the engine. 
The indicator on the pressure gauge should 
not drop rapidly. If necessary, check the 
system for leaks. Pay special attention to the 
compressor line and the compressor.

11. Fit the safety valve.

12. Fit the compressor control pipe to connection 

point (23) of the air dryer.

BRAKE SYSTEM AND COMPONENTS

2-4

©

 200423

Inspection and adjustment

5

ΧΦ65/75/85 series

6

2.3 INSPECTION, COMPRESSOR CONTROL

Remain at a safe distance from 
rotating and/or moving components.

1.

Bring the engine up to operating 
temperature.

2.

Bleed the system until the pressure is below 
the cut-in pressure. See "Technical data".

3.

Connect a pressure gauge
(test range 0 - 16 bar) to the test nipple of the 
tyre filling connection.

4.

Start the engine.

5.

When the pressure regulator cuts out 
(blows off), the pressure gauge should fall 
to approximately 0 bar.

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R600249