Brake pedal problems

[gwhamilton@gmail.com]

I’m looking for help with my brake issue on a 2013 Edge. This might be lengthy bit I want to put out everything I know. My initial problem was a soft pedal. It would go down smoothly and easily almost to the floor. I didn’t have much braking until I almost went full stroke. Seemed like a master cylinder. I had no external leaks. Talked to a few friends and got a consensus so I replaced the master cylinder with a Motorcraft part from rock auto. I bench bled the cylinder and installed. I vacuumed bled the brakes. Now I have a pedal that gives me slight deceleration as soon as I press the pedal and as I increase the pressure it becomes pretty firm without much more deceleration. It then takes a good bit of pressure to break through that firmness and I get more breaking. With the car off, a pump or 2 and the pedal is rock hard about half way down. I looked around online and read something about needing to actuate through emergency brake during rear brake bleeding. Is that a thing? Could that be my current problem? Any other ideas? TIA. 
greg

[Haz]

Beginning with your question on parking brake involvement during brake system bleeding, from the 2013 Edge Workshop Manual's...

 

Brake System Bleeding - General Procedures - 2013 Edge Workshop Manual.pdf (download link)

 

Vehicles with rear integral parking brake calipers

1. NOTE: Due to the complexity of the fluid path within the rear integral parking brake calipers, it is necessary to press and release the parking brake during the bleed procedure.

   Apply and release the parking brake 5 times. Loosen the rear bleeder screw. Leave open until clear, bubble-free brake fluid flows, then tighten the rear bleeder screw.
   • Repeat until clear, bubble-free fluid comes out.

 

 

With that said, the description of your Edge's initial problem is comparable to a failing/failed brake booster diaphram, for which Customer Satisfaction Program 13N02 was established to extend warranty coverage for brake booster replacement on certain 2010-2013 Edge/MKX models, based upon the vehicle build date.

 

13N02 - Brake Booster Warranty Extension - 2010 thru 2013 Edge and MKX.pdf (download link)

 

To determine if your Edge is eligible for this extended warranty coverage, input your Edge's VIN into this Ford website.

 

If the 13N02 program shows under 'Outstanding Field Actions', and your subsequent brake bleeding after actuating the parking brake per the Workshop Manual procedure does not improve your Edge's braking, it may be worth having your dealer evaluate the brake booster under the 13N02 Customer Satisfaction Program.

 

Good luck! 

 

Edited August 31, 2022 by Haz

[gwhamilton@gmail.com]

I finally was able to bleed the brake with parking brake cycling. The flow was bubble free but the problem still exists . I am over the miles for the booster replacement by Ford.

It seems like the pedal is easier to push while in park vs in drive. Does that sound normal, I guess I never noticed. I am wondering about the booster line check calve. This is also buried but I'll take the battery out for more access. I am wondering if that line goes somewhere else other than the booster. I got this image from Ford. I was able to remove one end and blow in it, it sounded like air was coming out somewhere. Should the check valve prevent this? I'd appreciate any ideas and I'll post my results. Thanks

 

[1004ron]

54 minutes ago, gwhamilton@gmail.com said:

I finally was able to bleed the brake with parking brake cycling. The flow was bubble free but the problem still exists . I am over the miles for the booster replacement by Ford.

It seems like the pedal is easier to push while in park vs in drive. Does that sound normal, I guess I never noticed. I am wondering about the booster line check calve. This is also buried but I'll take the battery out for more access. I am wondering if that line goes somewhere else other than the booster. I got this image from Ford. I was able to remove one end and blow in it, it sounded like air was coming out somewhere. Should the check valve prevent this? I'd appreciate any ideas and I'll post my results. Thanks

 

 

There will  be a little more manifold vacuum available to the brake booster when selected to Park, so that might be the reason why the pedal feels easier to push.

 

Most often the line from the manifold with its check-valve are exclusively used for the brake booster.

 

I would test the brake booster to see if it holds vacuum - it should hold vacuum for days if there no leaks - also check the vacuum hose and its check-valve.

 

 

[gwhamilton@gmail.com]

I was able to get the booster vacuum line off. Item 11 on the pic above is accurate. From the plenum it goes to the booster. I wasn't able to get the valve off the booster but plugged open end. When blowing on the end of the tube, I didn't detect any leakage so I think the line and check valve are good.

What is odd is while driving, I can press down slightly and get a little braking. If I increase pressure, I can "push through" the firm pedal and the brakes will grab.  I can modulate pressure and slow the car. It is workable but I want to fix this.

 

I have done the booster "depress pedal" test. With the engine off, I don't feel any power assist, the pedal is rock hard. When I start the car it doesn't really move. 

 

Is their a way to apply vacuum directly to the booster to actually test the booster? 

Edited September 8, 2022 by gwhamilton@gmail.com

[gwhamilton@gmail.com]

So tonight I tried apply about 17in of vacuum to the booster vacuum line looking to see if I could generate any brake assist. II measured the vacuum with my vacuum pump gage. I know there wasn't any flow but wanted to start low. I  didn't see any change in pedal feel so I increased the vacuum with without a any pedal difference. I took all of that off and started the car. I put my finger over the hole in the intake air duct. I couldn't feel any vacuum. Since that's where the vacuum for the booster comes from, shouldn't i be able to feel some kind of suction? I will go after the booster if I can be sure that's the problem. Any ideas?

[1004ron]

Yes, you should most certainly have vacuum at the source/intake manifold.

 

You should be able the test the effect of the brake booster with an alternate vacuum  source - if you use a vacuum pump you should be able to draw vacuum on the booster and it should hold for hours.

 

The vacuum booster is very good at holding vacuum - eg. if you get in the car many hours after it last ran, and press the brake without starting the engine, you can do that 3 to 4 times before the pedal gets hard, which is when the vacuum stored in the booster is depleted.

[gwhamilton@gmail.com]

So today I get aP2196 and P2197. The car was stumbling at a stop light every 30 seconds or so. It stalled once. I was able to run the ABS bleed test with a bi-directional scan tool. No help there. The pedal did go to the floor during the test which I don’t think is normal. I did hear a squeal when pushing the pedal about half way down. 
 

Anyway, I looked up the codes happening together and the first thing o read was a torn booster diaphragm. I don’t want to throw parts at it. Am I on firm ground replacing the booster? 

[1004ron]

The tests I described would confirm the condition of the boosters diaphragm - if you don't have a vacuum pump you could even do a rough assessment with a tube and your mouth.