S 350 (140.134) L6-3.5L DSL Turbo (603.971) (1995)
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Vacuum Pump: Testing and Inspection
Double Diaphragm
1. Connect suitable vacuum gauge to vacuum line between brake booster and check valve.
2. Start and operate engine at 750 RPM and note length of time required to obtain 14.8 inches Hg vacuum.
3. Elapsed time should measure 20-19 seconds with brake unit and all vacuum accessories vented and 12-13 seconds with brake unit only vented.
4. If elapsed time is not within specifications or if vacuum drops more than 5.9 inches Hg in 30 seconds, check vacuum system for leaks. If no leaks
are found, repair or replace vacuum pump as necessary.
