BLEEDING AIR FROM POWER
STEERING SYSTEMS
When bleeding air from a power steering system, please follow AGR’s bleeding Instructions
only. AGR has found the following method is the only proper way to bleed a system.
IMPORTANT
Do not start the engine until system is fully bled. If on a Hydro Boost system, follow hydro boost
bleeding procedures after bleeding the power steering system.
Failure to read and follow these instructions will void any warranty and possibly cause severe damage to your power steering and/or hydro boost brake components. If you have any questions please contact your dealer.
CAUTION
When to Bleed
• After any steering component replacement.
• If any part of the power steering system is opened for any reason.
Why Bleed
• To prevent pump damage.
• To ensure proper system operation.
• To stop steering system noise.
Before Bleeding
Carefully inspect the steering system.
• Hoses must not touch any other part of vehicle. Steering system noise could be caused
by the hose touching the frame, body, or engine.
• All hose connections must be tight. Loose connections might not leak but could allow
air into the system. Do not over tighten o-ring hoses as the o-ring might be crushed.
Check flare seat type connections for exact fit.
How to Bleed
IMPORTANT
Step 1
Do not start the engine until the system is fully bled. Doing so may cause damage to the
power steering components. Pump internals are metal on metal. Any air in the system can
cause metal to metal contact and damage.
Step 2
Raise the front wheels off the ground, or remove the pitman arm or tie rod.
Step 3
Turn steering wheel fully to the left.
Step 4
Fill fluid reservoir to “full cold” level. Leave cap off.
Use only clear, name brand, premium, racing or synthetic power steering fluid, such as Royal
Purple or Red Line. Do not use transmission fluid, as transmission fluid does not contain the
same friction inhibitors/additives and tends to breakdown and overheat. Use of transmission
fluid will void the warranty.
Step 5
Whith an assistant checking the fluid level and condition, turn the steering wheel slowly and
smoothly lock to lock until fluid level drops in pump reservoir. If fluid level has not dropped,
no fluid has moved through the system. This normally indicates a large bubble in the
reservoir or pump. Until this bubble passes, no fluid will circulate through the system.
—
On systems with coolers, winches, or Rock Ram assist you may need to cycle in excess
of 40 times.
—
Do not turn the steering wheel fast as this will cause the fluid to overflow the reservoir.
Trapped air may cause fluid to overflow. Thoroughly clean any spilled fluid to allow for
leak check.
Step 6
Check fluid constantly to ensure proper level and that no bubbles exist.
— If you see any signs of bubbles, recheck all connections then repeat the steps above.
— Fluid level should be steady (Rock Ram’s level will vary slightly).
Step 7 Disable engine from starting. (Non Hydro Boost Brake Systems)
—
Crank engine several revolutions. If fluid level drops, there is compressed air trapped in
the system. Repeat above steps until fluid level is stable.
—
If fluid foams while cranking, wait 10 minutes or more until dispersed air has time to
accumulate and purge through the reservoir.
Step 8
Continue above steps until fluid level remains constant and no air bubbles are visible.
Step 9
If you have a hydro boost brake system continue, if not skip to Step 11.
Hydro Boost Systems Only
These Hydro Boost specific instructions must be followed. Failure to follow these procedures can
cause your new high volume pump to become damaged or fail completely. Do not turn the
steering wheel while performing these procedures.
WARNING
—
Discharge the Hydro Boost brake unit by performing three full presses on the brake
pedal.
— Watch power steering reservoir for any bubbling, foaming or burping.
— Once foam clears, crank engine until it just catches and shut off.
— Discharge Hydro Boost unit with three full presses of the brake pedal.
— Repeat these steps until no air or foam is seen in the reservoir.
— If brake pedal feels soft, spongy or funny, system is not fully bled.
— Repeat above steps.
It is recommended on Ford Super Dutys with Hydro Boost Brakes, that the original pressure line from the Hydro Boost Unit to the pump be replaced with the updated line. Also that the Ball Joints be checked for lubrication, stiffness or wear.
If you have excessive metal in the fluid, the hydro boost will not bleed, is noisy or the brake pedal feels funny, call AGR Technical Support.
If you need to replace your hydro boost brake unit, AGR recommends replacing with a ported unit and not an OEM unit.
Step 10 Enable engine to start. With engine idling, maintain fluid level.
Step 11 Reinstall reservoir cap.
Step 12 Return wheels to center.
Step 13 Lower front wheels to ground or reinstall pitman arm or tie rod if removed in Step 2.
Step 14 Run engine for two minutes. Turn steering wheel in both directions.
Step 15 Do not hold steering wheel against the stops.
Step 16 Verify the following conditions:
— Smooth power assist
— Noiseless operation
— Proper fluid level
— No system leaks
— Proper fluid condition
— No bubbles, foam, or discoloration
Step 17 If all conditions are satisfied, the bleeding procedure is complete.
Step 18 If any problem exists, turn off engine and see Special Conditions below.
TIP
NOTE
Special Conditions
If you experience any of the conditions listed below, there is still air in the system.
• Foam or bubbles in fluid (fluid must be completely free of bubbles).
• Power steering fluid should not rise in the reservoir when the engine is turned off. If
this occurs, there is trapped air in the system.
• Be alert to periodic bubbles that could indicate a loose connection, leaky o-ring, or a
bad flare seat in either the pressure or return hose.
• Discolored fluid (milky, opaque, or light tan color).
Eliminating Air in the Power Steering System
Follow the steps below to eliminate air in the power steering system.
Step 1
Turn ignition off. Wait thirty minutes. Recheck hose connections. Repeat start up procedures.
If problem still exists, replace or check for possible causes including:
— Return hose clamps
— Return hose o-ring or flare seat
— Pressure hose o-ring or flare seat
— All other connections
Step 2 Fill system and repeat bleeding procedure for each possible cause.
Eliminating Noise in the Power Steering System
If you hear a whining or groaning noise originating from the pump after all air is out of
the system (if air is not out, see Special Conditions), then do the following:
Step 1 Check belts for slippage.
Step 2 Mark pulley and make sure it is not slipping on the shaft.
Step 3 With the engine running, recheck hoses for possible contact with frame, body, or engine. If no contact is found, cool fluid and repressurize system.
Step 4 After cooling fluid, start engine to come up to operating temperature and recheck.
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