How do you bleed a Ford Hydro-Boost brake booster?

Deplete the accumulator by pressing the brake pedal ten times with the engine off, apply 81-98 kPa (24-29 in-hg) vacuum to the power steering pump reservoir with Vacuum Pump D83L-7059-A or equivalent for three minutes, loosen the bleeder screw on top of the booster housing to extract air from the booster cavity, top off fluid, turn the steering wheel lock-to-lock (engine off, then running), and repeat the vacuum and bleeder-screw steps.

What fluid does the Hydro-Boost system use?

Motorcraft Mercon ATF or equivalent meeting Ford specification XT2-QDX, added to the power steering pump reservoir to bring the level to the full mark.

Where is the Hydro-Boost bleeder screw located?

On top of the booster housing, between the dash panel (01610) and the accumulator.

Why does the fluid level in the reservoir change during the procedure?

The power steering fluid level in the auxiliary reservoir rises and falls as the accumulator is charged and discharged; the document says to fill to the MAX line when the accumulator is discharged.

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Ford Hydro-Boost Brake Booster Bleeding Procedure - Service Instructions

Ford Hydro-Boost unit bleeding procedure power steering vacuum extraction steps

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Service procedure for bleeding a Hydro-Boost brake unit: deplete accumulator, apply 81-98 kPa (24-29 in-Hg) vacuum to the power steering reservoir, and bleed via the booster screw.

AI caption January 2012 · Photo 28 of 29

This document is a Ford service procedure for bleeding a Hydro-Boost brake booster unit. It begins with a note explaining that the power steering fluid level in the auxiliary reservoir rises and falls as the accumulator charges and discharges, and instructs filling to the MAX line when the accumulator is discharged. The ten-step procedure covers: depleting the accumulator by pumping the brake pedal ten times with the engine off; using Vacuum Pump D83L-7059-A (or equivalent) to apply 81-98 kPa (24-29 in-hg) of vacuum to the power steering pump reservoir (3E764) for three minutes; loosening the bleeder screw on top of the booster housing between the dash panel (01610) and accumulator to extract air from the booster cavity; adding Motorcraft Mercon ATF or equivalent meeting Ford specification XT2-QDX; turning the steering wheel lock-to-lock with the engine off and again with it running; and repeating the vacuum-extraction and bleeder-screw steps. An illustration (H10117-A) shows the hydro-boost unit and master cylinder oriented relative to the front of the engine. The final step (checking fluid level with engine running) is cut off at the page bottom. The document is undated and does not state a specific model or year application.

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Frequently asked questions

How do you bleed a Ford Hydro-Boost brake booster?: Deplete the accumulator by pressing the brake pedal ten times with the engine off, apply 81-98 kPa (24-29 in-hg) vacuum to the power steering pump reservoir with Vacuum Pump D83L-7059-A or equivalent for three minutes, loosen the bleeder screw on top of the booster housing to extract air from the booster cavity, top off fluid, turn the steering wheel lock-to-lock (engine off, then running), and repeat the vacuum and bleeder-screw steps.
What fluid does the Hydro-Boost system use?: Motorcraft Mercon ATF or equivalent meeting Ford specification XT2-QDX, added to the power steering pump reservoir to bring the level to the full mark.
Where is the Hydro-Boost bleeder screw located?: On top of the booster housing, between the dash panel (01610) and the accumulator.
How much vacuum is applied to the power steering reservoir during bleeding?: 81-98 kPa (24-29 in-hg) of vacuum, applied to the power steering pump reservoir (3E764) for three minutes using Vacuum Pump D83L-7059-A or equivalent.
Why does the fluid level in the reservoir change during the procedure?: The power steering fluid level in the auxiliary reservoir rises and falls as the accumulator is charged and discharged; the document says to fill to the MAX line when the accumulator is discharged.