AUDI A4 1998 B5 / 1.G Vacuum System Servicing Workshop Manual

87-185


Vacuum system, servicing

Fresh/recirculating air flap vacuum unit,
testing


Note:
Removing and installing vacuum unit page 87
-186
. - Detach hose -C- from two-way valve and connect vacuum pump US
8026, VAG1390 (or equivalent) to hose.
- Produce a vacuum (fresh/recirculating air flap moves against stop in
recirculating air mode position and remains in this position).
Pa
ge 1 of 4 Vacuum s
ystem, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.87.27

87-186

Fresh/recirculating air flap vacuum unit,
removing and installing


- Remove heater/air conditioner assembly
complete with instrument panel page 87
-159
.

Notes: - Remove screw A.
- Detach vacuum unit.

Setting X = 50 mm (1-31/32 in)
- Install in reverse order of removal.
Do not disassemble air conditioner.When installing, check for free operation.Test vacuum system page 87
-187
.
Pa
ge 2 of 4 Vacuum s
ystem, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.87.27

87-187

Vacuum supply and one-way valve,
testing


Notes: - Detach hose -B- from two-way valve (N63) and connect vacuum gauge
VAG1368 (or equivalent) to hose.
- Start engine and run at idle until the readout has stabilized.
- Switch off engine. Vacuum reading on gauge must not drop by more
than 50 mbar within 2 minutes.
Specification for vacuum when engine running: greater than 250 mbar.Removing and installing vacuum reservoir and one-way valve page 87
-188

Testing -N63-, output Diagnostic Test Mode (DTM) page 01
-42
.
Pa
ge 3 of 4 Vacuum s
ystem, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.87.27

87-188

Vacuum reservoir with one-way valve,
removing and installing


- Remove heater/air conditioner assembly
complete with instrument panel page 87
-159
.

Note:
Testing vacuum system page 87
-187
. - Remove screws -A-.
- Install in reverse order of removal.
Pa
ge 4 of 4 Vacuum s
ystem, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.87.27