Checking Pressure Accumulator Check Valve

5000 MODELS

1. With engine off, depress brake pedal approximately 20 times to reduce brake system pressure.
2. Disconnect electrical connector at and remove warning light switch.
3. Attach suitable pressure gauge with hollow bolt and copper washers to brake servo unit. Attach thick copper washer between brake servo unit and banjo fitting and the thin copper washer between hollow bolt and banjo fitting.
4. Start engine and idle until pressure gauge reads approximately 2030 psi, then turn ignition off.
5. Pump brake pedal until pressure drops to 1957 psi.
6. If pressure drops below 1885 psi within 5 minutes, replace pressure accumulator.