There's a school of thought on the Internet that a scan tool is needed to properly bleed the brakes to remove air from the lines and the anti-lock HCU. This is not entirely correct.

On a vehicle equipped with anti-lock brakes, "This procedure only needs to be performed if the 4-wheel anti-lock brake (4WABS) hydraulic control unit (HCU) has been replaced or if air is suspected in the HCU."

That's straight from the Ford factory technician database website.

Regular brake bleeding procedures won't hurt the ABS pump either, because the proper procedure is to bleed the system first, then connect the tool via the OBD II port, then repeat the system bleed.

Here are the directions from the Ford website:

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Four Wheel Anti-Lock Brake System (4WABS) Hydraulic Control Unit (HCU)
NOTE: This procedure only needs to be performed if the 4-wheel anti-lock brake (4WABS) hydraulic control unit (HCU) has been replaced or if air is suspected in the HCU.

1. Clean all dirt from and remove the brake master cylinder filler cap, and fill the brake master cylinder reservoir with the specified brake fluid.

1. Connect a clear waste line to the RH rear bleeder screw and the other end in a container partially filled with recommended brake fluid.

1. With the RH rear bleeder screw open, cycle the brake pedal until no more air is seen in the waste line.

1. Tighten the RH rear bleeder screw, and disconnect the waste line.

1. Repeat Steps 2, 3 and 4 for the LH rear bleeder screw, the RH front disc brake caliper bleeder screw, and the LH front disc brake caliper bleeder screw, in that order.

The procedure below only needs to be performed if the 4-wheel anti-lock brake (4WABS) hydraulic control unit (HCU) has been replaced or if air is suspected in the HCU.

1. Connect the scan tool DCL cable adapter into the vehicle data link connector (DLC) under the dash, and follow the scan tool instructions.

1. Repeat the system bleed procedure as outlined in Steps 1 through 5.

Caliper

1. NOTE: It is not necessary to do a complete brake system bleed if only the disc brake caliper was disconnected.

Place a box end wrench on the disc brake caliper bleeder screw. Attach a rubber drain tube to the disc brake caliper bleeder screw, and submerge the free end of the tube in a container partially filled with clean brake fluid.

Have an assistant pump the brake pedal (BP) (2B222) and then hold firm pressure on the brake pedal.

Loosen the disc brake caliper bleeder screw until a stream of brake fluid comes out. While the assistant maintains pressure on the brake pedal, tighten the disc brake caliper bleeder screw.

Repeat until clear, bubble-free fluid comes out.

Refill the brake master cylinder reservoir as necessary.

Tighten the disc brake caliper bleeder screw. Refer to Specifications.

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As you can see, no mention of a damaged ABS pump is mentioned if a procedure isn't followed while bleeding the system. It's not addressed because it's safe to do so.

So unless a person has replaced their Four Wheel Anti-Lock Brake System (4WABS) Hydraulic Control Unit (HCU), which the OP didn't do, or the HCU has malfunctioned or is damaged somehow, allowing air to enter the system, activating the ABS system to bleed it is unnecessary.

Stewart

 

Above post cut from the tech folder and moved, creating it's own thread so it can be linked back to the new format of the tech folder being finalized.

Stewart

 

As always good info from you. Thanks I too clip and pasted onto my hard drive as the internet is not always there for me.

 

I bled and bled and bled and bled the brakes again trying to get a pedal. I figured there was NO way Ford would let the EX go out with a pedal that went that close to the floor. Had to be air. Scan tool, hose off the bleeder in the fluid, pump up open close pump up open close, short rapid strokes, long slow strokes, flush with fresh fluid, gravity bleed, etc. etc. etc.

Then I read the mod about extending the plunger rod. Seemed like a patch for a bigger problem but BINGO. Like a whole different truck now. Thanks FTE.

 

HELLO WOTW2E; STEWART H.
I HAVE THE SAME PROBLEM AS ABOVE. I JUST REPLACED THE MASTER CYLINDER AND HYDRABOOST. THE BRAKE PEDAL GOES ALL THE WAY DOWN WITHOUT RESISTANCE. PLEASE HELP, HOW DID YOU EXTEND THE PLUNGER? THANKS A LOT!

 

First, did you do the brake bleeding procedure described above, EXACTLY as it instructs?

Second, please take the caps lock off before typing a post.

Caps lock is like yelling.



Thanks.

Stewart

 

sorry about the caps. caps at office work all day.
I understand about your bleeding procedure but it feels like something else. There's no pressure at all. Is it because I didn't do the bench bleeding of the master cylinder before install? There was another thread about adjusting the hydraboost rod?

 

Bleed your brakes first. You won't know if it's something else until you've properly bled your brakes.

Stewart

 

Ok. I will bleed tomorrow as you instructed.

Would you know about the mod for the hydraboost rod? Maybe its too short? It is mentioned on the thread that you were also.

Interestingly, before all of this. Out of the blue, my brake pedal would just sink down and loose about 50% of it's power. But I noticed that when I put the transmission on parking the pressure would return and then when I engage it on Drive, the pedal would sink again. (no leakage anywhere). Would that be the HCU?

Just brainstorming...frustrated...

Appreciate you help Stewart!

 

Mr. Stewart. Your recommendation worked! Priceless! Thank you. I"m subscribing to all your threads!

 

It's all good.

It's very difficult to diagnose problems described on the internet. Most times it's just a process of elimination, and the best place to start is at the beginning. That meant doing a proper bleed procedure on the brakes to eliminate that as the possible problem.

Stewart

 

He "works" harder for "free" on FTE than a lot of folks do at certain jobs! His moderator duties are also very appreciated. We also have a bunch of wonder techs and diyers who share their experiences..

 

"Connect a clear waste line to the RH rear bleeder screw and the other end in a container partially filled with recommended brake fluid.

With the RH rear bleeder screw open, cycle the brake pedal until no more air is seen in the waste line.
Tighten the RH rear bleeder screw, and disconnect the waste line.

Repeat Steps 2, 3 and 4 for the LH rear bleeder screw, the RH front disc brake caliper bleeder screw, and the LH front disc brake caliper bleeder screw, in that order."


Can the above procedure be done with a vacuum pump instead of having an assistant pump the brake pedal?

Curt

 

You mean like with a Motive brake bleeder? If so, then yes.

Stewart

 

I'm not sure what a Motive bleeder is, but I was planning on using a Mity Vac pump. Same type of thing I guess?

Thanks,

Curt