EHCU Bleed procedure
 

Had an OEM brake hose part. Given its 8 years in service, no surprise although I'd thought it would go longer.

So, how do you bleed an EHCU when it has air everywhere? The hose parted on the road and didn't figure it out until there was alot of air everywhere.

After much internet searching found a webpage entry speaking to doing it by repetitive brake applications causing engagement of the ABS feature.

Skeptical? Yeah.

But out here where I live I had to at least make it roadable to get to a Ford dealer to get it bled by their computer.

Bought a pressure bleeder and bled the heck out of the calipers and foundation system. Then across two days took it out on backroads (covered with several inches of hardpacked snow) and did the braking thing. Brakes worked but not comfortably. Mostly to ensure I was safe to get to a dealer.

Hm-m-m... came out on day two and had to add about a cup of fluid to the reservoir before going out...

Started up and no ABS light! Hm-m-m...

Took it out and the ABS feature worked just fine and... Still no yellow ABS light. But had the red Brakes light... Came in to park it and bleed the calipers again to ensure no air in the foundation brake system... the red light went out.

Bled each caliper for 5 minutes: no air bubbles.

Back out and to the Post Office on hard surface road. Repetitive brake applications on paved road and it worked fine... no yellow ABS or red brake system lights and no check brake system readout either.

Conclusion: the ABS system has a pressure pump that cycles when you open a door or click the unlock button on your key fob. I believe that this also provides a self purging capability for the ABS. You can't just drive away after system work that opens it up and introduces air. But if you can take a day or two after doing work, along with a safe place to test it, the system can bleed itself with out the software.

My experience, it is only provided for info and discussion and is not a recommendation to do this procedure yourself.

Re: EHCU Bleed procedure
 

You normally use a bi-directional scan tool that can actuate the ABS controller to bleed that system. Once that is complete, the calipers are bled and you will be complete. By repeated braking on surfaces that cause the ABS to activate, you are doing the same basic thing but at a slower rate.

There is also the possibility that the air you force out by braking can migrate back into the ABS controller but if you follow your braking by a conventional bleed fairly soon, it should work just like you experienced.

Re: EHCU Bleed procedure
 

I have the shop manuals and understand the procedure. Haven't chosen to split for the hardware & software. The Ford dealer is 80 miles away and so I needed a method to make it roadable.

What you described is what I observed. I did follow the second road actuation routine by a good long bleed (5 minutes @ caliper) and by just a few minutes from the road. There were no bubbles in this bleed sequence. Curiously what I saw after the initial road actuation routine was that the air migrated back into the brake fluid reservoir (I had to add about a cup of fluid the next morning).

So, what I ended up doing was installing the new hoses & calipers, bleeding each caliper extensively, doing the road routine, adding fluid, doing the road routine again, and then another good bleed on each caliper.

Probably ran a gallon or more of fluid through the system with all of the bleeds. This was intentional as I wanted to give the EHCU plenty of opportunity to surrender every last bubble of air.

What I set out to do was simply make it safely roadable in order to get to a Ford dealer. What I ended up doing, serendipitously, was doing a bleed of the EHCU. As best I can tell it is fully safe right now.

Re: EHCU Bleed procedure
 

I did it as well about 6 months ago [described on site] with gravity and pressure and road driving on gravel, as well. I have had no problems since and did not get the dealer to do it, either!

Re: EHCU Bleed procedure
 

Apologies for digging up an old thread, but is a link for this? I've got to replace the front brake lines to pass state inspection. I'm going to attempt to follow the above advice, but would love to see as much info as possible.