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Checking for leaks > < Connecting vacuum gauge for brake servoVAS 6721

A1

Checking vacuum generation
Checking vacuum generation
  Note
t  The mean atmospheric pressure at sea level is 1013 mbar and decreases rapidly with increasing altitude (approx. 100 mbar per 1,000 m of altitude). Fluctuations at different locations and times also influence vacuum generation.
t  A cold engine, an active air-conditioning system as well as engine idling have an adverse influence on vacuum generation.
–  Before starting work, check all vacuum hoses for damage (e.g. cracks or animal bites) and make sure they are correctly and securely attached.
–  Connect vacuum gauge for brake servo -VAS 6721- → Chapter.
–  Open shut-off valve -A-.
   
–  Close shut-off valves -B+C-.
–  Start warm engine (>60° C), press accelerator briefly (engine speed greater than 2000/min).
–  Read indicated value.
Under normal conditions (see notes), the generated vacuum should be between 600 and 950 mbar (depending on engine version).
If the specified value is not obtained even though the test conditions (see notes) have been met, the vacuum system must first be checked for leaks.
–  For comparison purposes, generate the vacuum with the hand vacuum pump -VAS 6213- → Chapter.
Open shut-off valve -B- to facilitate removal of hose connections and adapter.
  N47-10210

Checking for leaks > < Connecting vacuum gauge for brake servoVAS 6721