Vacuum Advance Unit, Checking For Leakage

Distributor vacuum unit, leak checking

Work sequence

- connect vacuum tester between intake manifold and retard connection on vacuum unit
- plug vacuum hose for retard connection
- set vacuum tester to allow vacuum to pass through
- start engine and run at idle
- disconnect hose from advance connection on vacuum unit
- set vacuum tester so that it holds vacuum on side connected to vacuum unit

Note: Vacuum registered on tester must not drop by more than 10% within 1 minute

- connect vacuum tester between throttle valve housing and advance connection on vacuum unit
- set vacuum tester to allow vacuum to pass through
- increase engine speed until reading on vacuum tester is higher than 240-280 mbar (180-210 mm Hg)
- if no vacuum is registered on tester, check if connection at throttle valve housing is blocked
- set vacuum tester so that it holds vacuum on side connected to vacuum unit

Note: Vacuum registered on tester must not drop by more than 10% within 1 minute