Checking electric pressure regulator unit

AR42.20-L-0002B

Checking electric pressure regulator unit

9.12.09



Checking

1

Bleed parking brake system

2

Connect test kit to test connection (H1) between non-return valve (F) and compressed air reservoir V1 (C2).

 Test kit

*360589002100

3

Fill parking brake system with compressed air until pressure regulator switches off

 Compare cutoff pressure measured at test connection (H1) with specified value. If the measured cutoff pressure and specified pressure are different:

*BE42.20-N-1002-01C

Replace pressure switch (compressor cut-out) B74 (E2) (color coding white).

 Test kit

*360589002100

4

Lower reservoir pressure in parking brake system until the cut-in pressure of the pressure regulator is reached

 Compare cut-in pressure measured at test connection (H1) with specified value. If the cut-in pressure and specified value are different:

*BE42.20-N-1005-01C

Replace pressure switch (compressor cut-in) B75 (E4) (color coding brown)

 Test kit

*360589002100

5

Check control range of pressure regulator between cut-in and cutoff pressure

 Compare difference in pressure measured between cut-in and cutoff pressure with specified value. If the difference between the cut-in and cutoff pressure and specified value are different:

*BE42.20-N-1004-01C

Check pressure switch (compressor cutout) B74 (E2) (color coding white) and pressure switch (compressor cut-in) B75 (E4) (color coding brown).

 Test kit

*360589002100

6

Remove test kit from test connection (H1) between non-return valve (F) and compressed air reservoir V1 (C2)

 Test kit

*360589002100

Number

Designation

Models
668, 670
as of VIN 101651 except code B16, except
670.398/4

BE42.20-N-1002-01C

Cut-off pressure

bar

12.5 (-0.5)

BE42.20-N-1004-01C

Switching range

bar

10.5...12.5

BE42.20-N-1005-01C

Cut-in pressure

bar

11 (-0.5)