Brake Booster

WARNING: This page is about a different car, the 2002 Ford RV Cutaway, 2002 Ford Econoline, 2002 Ford E550 Super Duty, 2002 Ford E450 Super Duty, and 2002 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the brake booster for the following:

Excessive corrosion or damage
Vacuum connections for leakage
Vacuum hoses for kinks or leakage
Brake booster check valve for correct operation

Changes in the brake pedal feel or travel are indicators that something could be wrong in the brake system. GO to SYMPTOM CHART for abnormal condition diagnosis.

With the engine OFF, apply the brake pedal several times to deplete the power assist reserve in the brake booster.
Hold the brake pedal in the applied position.
Start the engine.
The brake pedal should drop slightly after the engine starts.
On vacuum brake booster equipped vehicles, if the brake pedal does not drop after the engine is started, check for vacuum at the brake booster.
- With the engine OFF, disconnect the vacuum hose and check valve at the brake booster.
- Vacuum should be heard escaping from the brake booster.
If vacuum is not available at the brake booster, check for vacuum at the source and check the vacuum hose for leaks.
- On vehicles without a vacuum pump, check for vacuum at the engine. For additional information, refer to ENGINE SYSTEM-GENERAL INFORMATION .
- On vacuum pump equipped vehicles, inspect the accessory drive and accessory drive belt. For additional information, refer to SPECIFICATIONS & DRIVE BELT ROUTING .
If vacuum is available at the brake booster and no power assist is felt, install a new brake booster and retest the system. For additional information, refer to DISC & DRUM .
On Hydro-Boost(R) equipped vehicles, if the brake pedal does not drop after the engine is started, check the power steering pump pressure and flow. For additional information, refer to STEERING SYSTEM-GENERAL INFORMATION .
If power steering pump pressure is available to the Hydro-Boost(R) and no power assist is felt, install a new Hydro - Boost(R) brake booster and retest the system. For additional information, refer to DISC & DRUM .
ACCUMULATOR
Start and run the engine.
Stop the engine.
Apply the brakes. The accumulator in the Hydro-Boost power brake booster should retain enough pressure for at least two power-assisted brake operations. If no power assist is felt, install a new Hydro-Boost power brake booster and retest the system.