how can you tell if your power steering pump is bad or if your hydroboost is the problem? power steering pump is whining and when you apply the brakes they sort of pulse and go to the floor slowly.

 

Check your fluid level first, it you open the cap and you see foamy looking stuff you are low and getting air. When I changed my power steering fluid (which is ATF) I got air in the system and mine had the whining, pulse and to the floor. Once I got the fluid level correct and turned the wheel and cycled the brakes to get all the air out (does not take long) If the level is good, flush the system by adding fluid while you drain the old stuff. l disconnected the return line just below the cap

 

power steering fluid level is fine, bright red

 

When my hydroboost went out, I had fluid leaking under my brake pedal in cab like when a master cylinder seal leaks and I had a loud groaning when I would turn the steering wheel. Was a messy job to replace it

 

cab is dry, brake fluid fine, did notice when I ran the engine and turned the steering wheel back and forth the power steering fluid did foam, also while engine running pumped brakes the power steering fluid also foamed. the pump whines when turning wheel and or when applying the brakes.

 

You have air in the system, work the steering wheel back and forth and cycle the brakes. As the air bleeds off the fluid level will drop, so keep a eye on the level. These power steering units Ford uses and have used for years are not the best to start off with.

 

Brake Master Cylinder Test:

Disconnect the brake lines at the brake master cylinder.

Plug the outlet ports of the brake master cylinder.

Apply the brakes. If brake pedal height cannot be maintained, the brake master cylinder has an internal leak and must be replaced.

Brake Booster Testing:

With the transmission (7003) in NEUTRAL and the engine (6007) stopped, apply the brakes several times to exhaust the vacuum in the vacuum boost system or the pressure in the Hydro-Boost system.

Hold the brake pedal in the applied position.

Start the engine.

If the power brake system is functioning properly, the brake pedal can be felt to move downward after the engine starts.

With a vacuum type power brake booster, if engine vacuum is available to the power brake booster and no power assist is felt, replace the power brake booster and retest the system.

If power steering pump pressure is available to the Hydro-Boost power brake booster and no power assist is felt, replace the Hydro-Boost power brake booster and retest the system.

If power steering pump pressure is not available at the Hydro-Boost power brake booster, check the power steering pump pressure and flow:

Flow Rate @ 74° - 80° C (165° - 175° F) and Engine Speed Set at Idle 8-9.5 liters/minute (2.1-2.5 gpm)

Pressure @ 74° - 80° C (165° - 175° F) and Engine Speed Set at Idle 1034 kPa (150 psi)

On a Hydro-Max booster system, if power is available at the electric pump and no power assist is felt, replace the Hydro-Max booster assembly and retest the system.

If power is not available at the electric pump, correct the electrical concern and retest the system. 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, replace the Hydro-Boost power brake booster and retest the system.

Air should be removed from the system using a vacuum evacuation tool and adapter.