Volkswagen Golf Service & Repair Manual: Checking vacuum generation
 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-. |
|
|
|
| – |
Close cut-off valves -B+C-. |
| – |
Start warm engine (>60°C), press accelerator briefly (engine
speed above 2,000 rpm). |
| – |
Read indicated measured value. |
| Normally (see notes), the vacuum that is generated should be
between 600 and 950 mbar (depending on engine size). |
| If the measured value is not reached even through the
preconditions (see notes) have been met, the vacuum system must
first be checked for leaks. |
| – |
For comparison purposes, generate the vacuum with the manual
vacuum pump -VAS 6213-
→ Chapter. |
| Open cut-off valve -B- to
facilitate removal of hose connections and adapter. |
|
|
|
Special tools and workshop equipment
required
Vacuum gauge for brake servo -VAS 6721-
...
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 ...
Other materials:
Specified values for wheel alignment, multi-link suspension, Golf
These specifications apply to all engines.
Explanations regarding PR numbers
→ Chapter „Vehicle data sticker“.
Front axle
Basic
running gear
Sports
running gear
Raised
running gear
DCC
running gear
...
Cavity sealing, rear body
Cavity sealing, wheel housing and underbody at rear, 4-Motion
vehicles
Illustration shows left side. The right side is the mirror image.
Note
The indicated areas have been treated with cavity sealant and must
be resealed following repairs.
...
Side view
Fig. 1 Overview of the driver side
Key for :
Roof aerial
Tank flap
Exterior door release lever
Exterior mirrors
Additional turn signal
Surround lighting
Jacking points
...
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Connecting vacuum gauge for brake servo -VAS 6721-
Checking for leaks