Volkswagen Golf Service & Repair Manual: Checking for leaks
 Note
| The average air pressure of the earth's atmosphere at sea
level is 1013 mbar and decreases steeply as the altitude
increases (approx. 100 mbar/1,000 m altitude). Local and time
fluctuations also influence vacuum generation. |
| A cold engine, a switched-on air-conditioning system as well
as engine idling have an adverse influence on generation of a
vacuum. |
| – |
Before starting work, check all vacuum hoses for damage
(e.g. cracks or marten bite) and to check that they are
correctly and firmly attached |
| – |
Connect brake servo vacuum gauge -VAS 6721-
→ Chapter. |
| – |
Open cut-off valve -A-. |
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|
| – |
Close cut-off valves -B+C-. |
| – |
Start warm engine (>60°C), press accelerator briefly (engine
speed above 2,000 rpm). |
| Normally (see notes), the vacuum that is generated should be
between 600 and 950 mbar (depending on engine size). |
|
|
|
| – |
Open cut-off valve -C- to
evacuate brake servo. |
| – |
Read and make a note of measured value shown. |
| A vacuum decrease of 400 mbar in 12 hours is permissible. |
| If the vacuum decrease is greater, check for leaks in the
vicinity of ... |
| 2 - |
Non-return valve of vacuum hoses with connectors and vacuum
pump/suction pipe. |
| If there are large leaks, the vacuum decreases steeply
within a few seconds. |
| Vacuum check in vicinity of brake servo: |
|
|
|
| – |
After generation of vacuum, close cut-off valve
-A- to check brake servo vacuum
system. |
| Vacuum check in vicinity of non-return valve, vacuum hoses
with connectors and vacuum pump or intake manifold: |
|
|
|
| – |
Once vacuum has been generated, close shut-off valve
-C- to check vacuum system from
brake servo vacuum gauge -VAS 6721- to intake manifold or to
vacuum pump. |
| Open cut-off valve -B- to
facilitate removal of hose connections and adapter. |
|
|
|
Note
The average air pressure of the earth's atmosphere at sea
level is 1013 mbar and decreases steeply as the altitude
increases (approx. 100 mb ...
In certain cases, vacuum can be generated with the manual
vacuum pump -VAS 6213- instead of with the engine or the vacuum
pump.
–
...
Other materials:
Valve dimensions
Note
Inlet and exhaust valves must not be reworked. Only
lapping-in is permitted.
Dimension
Inlet
valve
Exhaust
valve
Diameter a
...
Checklist
Never carry out any work on the engine or in the engine compartment
if you are not familiar with the requisite procedures and general safety requirements,
or if you only have access to incorrect operating equipment, service fluids,
and unsuitable tools . The work should be carried ou ...
Run-flat tyres, PAX, checking
When checking a tyre, look out especially for the following
criteria:
Surface erosion or ripples on the inner side (inflation
pressure was too low or not sufficient for the load)
...
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Checking vacuum generation
Vacuum generation with manual vacuum pump -VAS 6213-