128. Vacuum Modulator Inspection

- Tools Required
- J 23738-A Hand Vacuum Pump (or equivalent)
- J 36619 Modulator Checking Tool





1. Inspect the modulator components for the follow conditions:
- A damaged modulator valve (34)
- A damaged modulator assembly (32)
- A damaged modulator O-ring seal (33)
- A damaged modulator retainer (31)

2. Install J23738-A or equivalent onto the vacuum pipe nipple of the modulator assembly.
3. Apply 15 kPa of vacuum to the modulator assembly (32) under the following criteria:
- Hold the vacuum for 30 seconds
- Confirm that the plunger retracts into the modulator assembly

4. Remove J23738-A from the modulator assembly.





5. Use a modulator assembly that is known to be good.
6. Install J 36619 between the good modulator and the modulator to be checked.
7. Push the modulators towards each other.
8. Note the indicator on J 36619,
- If the indicator line (1) is visible, the modulator is OK
- If the indicator line moves out of view, replace the modulator