Okay, may be my FEH 2005 different but I did front brake's pads examination by removing them when right front wheel bearing changing, no battery was disconnected or fuse removed. Key was in position to allowing steering wheel to be rotated. So why system was not pressurized?

 

Ok, here is what it says verbatum in my '06 Mercury Mariner HYBRID (can't believe you'd actually think I was so stupid as to not consider that) manual.

Pg. 295

"Brake pad replacement information

The Regenerative Braking System checks the integrity of the brake system at times when the vehicle is parked. This is done by developing brake pressure for short periods of time. In order to change the brake pads, it is necessary to enter the Pad Service Mode. This will prevent brake pressure from being applied.

To enter the Pad Service Mode, perform the following with the vehicle stationary:
1. Place the vehicle in Park and turn the ignition to the ON position.
2. Apply the brake pedal.
3. Turn the ignition OFF, then ON three times and then release the brake pedal. The total time elapsed for the three ignition cycles and brake release must be less than 3 seconds.

The brake warning lamp will:
- flash as stored hydraulic pressure is released.
- remain illuminated once the pressure is completely released.
- flash if the brake is applied.

To exit the Pad Service Mode:

1. Apply the brake pedal and turn the ignition OFF then ON. This will cause brake pressure to be developed within the brake system. Once the brake pressure is developed, the brake warning light will turn off.
2. The Pad Service Mode will also be exited if the gear shift leer is moved from the (P) Park position, the vehicle is moved (wheels rotate) or the ignition is turned OFF.

NOTE: The brake system on this vehicle can only be bled at a authorize dealer."


Ok, now that's straight from the: "Mercury Mariner Hybrid Owner's Guide"

 

All that said, when I did the rear brakes, I placed a screw driver handle between the brake pads while I dressed the brake disk just in case so it wouldn't blow out the piston should I have screwed something up and the system pressurized anyway.

 

FWIW, this same information exist in the 2008 FEH/MMH owners guide as well on Page 283.

 

It should be in all the FEH/MMH Owners Manuals because it's in mine also. I didn't think to look for brake pad replacement there and certainly don't expect the dealers would follow that procedure if it's not in the Workshop Manual. It may be that because of liability the dealer remove the calipers to inspect and change the seals or may have to replace the calipers which would call for bleeding and replacing the brake fluid.

The other thing that concerns me is leaving the Key in the On position for long periods of time. Normally with the key On the HV battery continues to drain into the 12V system. If it was a matter of quickly changing just the pads without turning the rotors I guess that would be the way to go. I've never had a good experience going that route myself because of the rotors always have groves which cause more brake problems after the pad change. For that reason I would spend the extra money and just replace the rotors with new ones and address the calipers when and if they go bad.

GaryG

 

Wouldn't waiting the 12 minutes then pulling fuses 24(50A) and 31(50A) located in battery junction box suffice in servicing the brakes?. I wouldn't think I would want to leave the key in the ignition period that's breaking one of the most important safety rules there is!!

 

I guess you can be as cautious as you feel necessary. I didn't feel it was necessary to do anything more than just do the service mode procedure. I changed the pads before they were completely worn. Sure the rotors weren't compltely smooth, but they were in plenty good enough shape to me. Just as a precaution, I always hit them with some sand paper to knock the gloss off of them. I believe it helps the new pads seat against the less than perfectly smooth rotors. Still, doesn't take all that long. I didn't worry about running down the 12V battery. I was sure to turn off any other power drain such as radio or climate control fan. Made sure doors were closed so no interior lights were on either.

 

I agree, I want all power Off and that includes pulling the orange plug on the HV battery. I want the SoC levels in the 12V and HV battery the same as when I started the Job myself. If I run into trouble and need to change other parts, I know I have time to order and get them while the batteries are sleeping. The real fact is I always stop with regen braking and driving without brakes (DWB) and expect my original brake pads and drums to last as long as I own the FEHs. I will also know right away if I have rust or anything causing any wheel drag because of the way I monitor mileage and neutral coasting.

GaryG

 

It would be interesting to know if the service mode procedure ending with the Key ON shuts power from the HV battery and other 12V systems. For instance, normally with the Key ON 12V power is supplied to the TBCM, TCM and the electronic coolant pump (MECP) etc. To test if the MECP is working properly, you normally turn the Key ON and feel the pump with the engine Off. This should be easy to check but what about the other systems?

GaryG

 

I have enjoyed my 2006 FEH and have 60k miles. I've followed all recommended maintenance etc. Two weeks ago the brake warning light started coming on occasionally. I checked the emergency brake..no problem, the car would brake as it normally would, I checked the brake fluid levels..no problem..but the light and alarm would still come on especially when hitting a bump or turning. I thought maybe a sensor and electric problem with the dash. Took it to the dealer who said they couldn't get the light to come on when they drove it..I explained I wasn't imagining it. They took down more info..I became wary of if they knew what they were doing. I was in shock ( to say it mildly) when they said they hooked it up to a diagnostic machine and what I needed was a new master cylinder ($1800.) If the brake light still continued "Ford" recommended a new ABS system ($4500.) Even after they would do this work they couldn't "guarantee" the problem would be solved. I asked why there wouldn't be some other physical evidence that the brakes were bad, ie fluid leak, squeaking, spongy breaks..and was told they didn't know but they had to advise me that this was the "repair" that Ford recommended. I haven't done anything as I want to get a 2nd opinion. After reading what alot of you have said I'm really stumped! Any advice? I too am afraid to drive it!

I've made copy of this from Ford Escape Hybrid Maintenance & Repair forum, hope nobody have had same problem here.