Vacuum Pump (Diesel)
WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 2004 Ford RV Cutaway, 2004 Ford Econoline, 2004 Ford E450 Super Duty, 2004 Ford Cutaway, and 2003 Ford RV Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- Turn key off, disconnect vacuum line and connect a vacuum gauge with a "T" fitting to lower part of dash mounted plastic check valve. See Fig 1. Start engine and allow to run at idle until vacuum reaches 17-21 in. Hg.
- Turn ignition off and observe vacuum gauge for one minute. If vacuum drops more than 1 in. Hg, replace power brake booster check valve. If vacuum does not drop more than 1 in. Hg, go to next step.
- Reconnect vacuum gauge in same point as in step 1, but leave rest of system connected. Start engine and allow engine to run at idle until vacuum reaches 17-21 in. Hg. Turn ignition off and observe vacuum gauge for one minute.
- If vacuum drops more than 1 in. Hg, disconnect each component one at a time and repeat test procedures in step 3 until leaking component is found. Plug disconnected vacuum line while performing test procedures. Repair or replace defective component as required. On diesel engine with dash mounted power brake booster, replace power brake booster check valve also. If vacuum does not drop more than one in. Hg, go to next step.
- Start engine and run engine until vacuum reaches 17-21 in. Hg. Turn ignition off and push down on brake pedal for a few seconds and release. If vacuum pressure drops to zero in. Hg, replace power brake booster. If vacuum pressure does not drop to zero in. Hg, system is okay. Remove vacuum gauge and reconnect all vacuum lines.