Long brake saga. Need advice on moving forward.

[Screeling]

Hi guys,

I've been a lurker for a while, but never really posted. Really looking for some advice on my brake situation. I'll try to be brief. This is for a 2012 Ford Edge SEL EcoBoost.

 

A. 2012-2013 - Brake booster goes bad. Replaced under warranty.

B. 2017 November - Brake pedal goes all the way to the floor when driving it. Still have brake power though.

C. 2017 December - Dealer #1 in town says master cylinder is bad and brake booster is not. They want to replace booster anyway (under warranty). Master cylinder not going to be covered. Booster is replaced, problem not resolved; pedal still goes to floor but has stopping power. No more confidence in these guys since they were replacing parts they stated were not defective.

D. 2018 January - Driving home, pedal magically now behaving like normal. Normal engagement, everything feels like I was accustomed to it.

E. 2018 May - Coming down a hill while using brakes. Hit a bump and pedal goes to floor while braking, but still have stopping power (almost crapped my pants too, but that's beside the point).

F. 2018 early June - Take it to a local mom-n-pop shop under recommendation from a buddy who is a wrecker and said they were honest. They say master cylinder is bad. I agree to replace it. They drip brake fluid into the booster at this time and booster has to get replaced. They admit problem doesn't seem to be fixed, and don't charge me for it. They state the only thing they see it could be is the line to the ABS box requires a computer-controlled bleed, which their computer couldn't do. Say I have to take it elsewhere, but haven't charged me anything.

G. 2018 mid June - New problem introduced. Brakes now spongy as all hell, but still go to the floor and still have stopping power. Now having throttle issues where acceleration cuts out on me unless I gun the engine and cruise control will not let me set a speed and actually cruise (though it turns on). I also notice that if I put my foot under the brake pedal and lift, it comes up about 1/4" and cruise will now work properly at that point. Gas mileage gauge also seems to show a 2-4 mpg increase on a slight uphill when I lift the pedal. Every application of the brake requires the lift to use cruise.

H. 2018 late June - Mom-n-pop shop replaces brake switch. Doesn't fix the lift-to-cruise problem. Dude tweaks some stuff at the pedal. Can now use cruise, but all indications seem to be brakes still engaging as mentioned in G.

I. 2018 late June - Car taken to smaller dealer (Dealer #2) in next town over. They bleed the ABS box but no fix. They say the only thing they can see it being is the hydraulic control unit. They replace it. I have normal power brakes again, but pedal travel distance until brake engagement seems inconsistent sometimes. Lift-for-cruise-control problem still present. Subjectively, it also seemed like the car is having to rev harder and it seemed like lifting the pedal would make it sound/feel like what I thought I remembered as normal. Gas mileage gauge also seems to show a 2-4 mpg increase on a slight uphill when I lift the pedal.

J. 2018 early July - Taken back to Dealer #2. They adjust brake switch and fix cruise issue. They also state the right front caliper is locking up. They replace it.

K. Present - I just got it back today. Cruise indeed seems to be fixed. Car doesn't always seem to be revving harder, but sometimes I think it is. I notice I can still lift the pedal that last 1/4" and in one place, it looked like that gave me that small mpg increase mentioned earlier. Only replicated that one time out of a handful though.

 

I'm not sure what to do next. I'm living on student loans and can't keep shelling out money for this. I'm not even sure I remember what normal feels like anymore. I also don't know if that last 1/4" I can lift the pedal was always there or not (does anybody else's do this?). I just know I'm losing a lot of money and don't know what else to do. Thanks for any advice.

 

Edited to add a missing fact.

Edited July 11, 2018 by Screeling

[WWWPerfA_ZN0W]

Umm ... how many miles on it?

 

Dealer def missed the boat by not doing an ABS bleed way back when. Still does not seem to have done. The stoplamp switch is what I assume got replaced, because it is easy to wreck it during brake booster installation.

 

Throttle body issues - if 2011+ and 3.5/3.7 engine, might need replacement. Easy 5 minute swap, relatively inexpensive parts on rockauto.com. 2007-10 TBs are more expensive, but swap again is a nobrainer. Have not seen issues on the 2.0 Ecoboost, but SOME failures of the TB motor on the 3.5 Ecoboost.

 

Although you do not live in the salt belt, regular brake maintenance is key to pad/rotor/caliper life. At a very mininum, caliper slide pins need to be de-rusted and greased with hightemp ceramic brake grease to keep functioning well.

Edited July 12, 2018 by WWWPerfA_ZN0W

[Screeling]

Sorry, I'm at 68k miles right now. Also, for the last 3 years, I've lived in Missouri so I think your salt belt comment was from when I still lived in AZ.

 

As for the throttle body thing, I guess I just don't see problems with throttle, particularly acceleration, when I do the pedal lift.

 

As a follow up to yesterday's post: I reset my average gas mpg gauge for the trip to work today with the intent of not doing pedal lifts to see what I get. Got about 17 mpg, which is pretty unheard of. I'm always above 20. Also, coming down a hill with cruise disabled and coasting, my car was still slowing down. When I decided to do the pedal lift, then coasting has me gaining speed. Also noticed when braking at the bottom of the hill, the pedal engaged the brake immediately with no travel, whereas at other times it engages after depressing a half inch to inch or so. I find it hard to believe multiple calipers are locking up after all this tinkering.

[I'manedgeowner]

I would think the first thing done was replace the brake fluid. Next, pressure test your brake lines. You'd probably be amazed at how big a brake line can get without leaking or blowing out. They can look like balloons.

 

Ford is a bit notorious for the feel of the brake pedal and the pedal going to the floor but the brakes still working. I'm not sure what you mean by "bleed the ABS brake box?" I'm also not familiar with what type of ABS control your car has. Whether your brake proportioning valve is part of your ABS module or separate, it needs to be checked along with the fluid reservoir your system uses. That's the separate ABS reservoir.

 

I would also guess that your throttle problems are from the booster work. Was the booster check valve tested before replacing the booster? Was throttle vacuum tested to make sure it's not getting back to the booster? This could be your throttle problem.

 

Not being familiar with your car I'm just guessing by the symptoms you've described by the brake systems I'm familiar with..

[Screeling]

I would think the first thing done was replace the brake fluid. Next, pressure test your brake lines. You'd probably be amazed at how big a brake line can get without leaking or blowing out. They can look like balloons.

 

Ford is a bit notorious for the feel of the brake pedal and the pedal going to the floor but the brakes still working. I'm not sure what you mean by "bleed the ABS brake box?" I'm also not familiar with what type of ABS control your car has. Whether your brake proportioning valve is part of your ABS module or separate, it needs to be checked along with the fluid reservoir your system uses. That's the separate ABS reservoir.

 

I would also guess that your throttle problems are from the booster work. Was the booster check valve tested before replacing the booster? Was throttle vacuum tested to make sure it's not getting back to the booster? This could be your throttle problem.

 

Not being familiar with your car I'm just guessing by the symptoms you've described by the brake systems I'm familiar with..

 

The lines have been bled multiple times over this whole ordeal, by every shop that touched it above. I didn't mention that, but guess I figured that was assumed, given the master cylinder replacement.

 

As for the throttle problem, I may not be describing it correctly. The extra reving of the engine is usually subtle and it's like trying to drive the same speed while having the brake slightly depressed. The engine is working a little harder to maintain the speed until I lift the pedal up that last 1/4". Then the engine behaves as normal because the brake isn't engaging anymore.

 

I drove it some more today and it seems like when I come to a complete stop, the brake will disengage enough on its own so that it's no longer engaged on the rotor. I can still lift up the pedal, but the brake seems fully open and I'll get normal mileage. If I brake to slow down but don't have to stop (like turning a corner), then it seems like the brake stays engaged. The longer it stays this way, the more stiff the brake pedal feels when I depress it (which I assumed was due to heat from constant engagement). I'm still trying to test this last part out. I'm having trouble figuring out ways to test this so I can characterize the behavior properly.

[I'manedgeowner]

Bleeding and flushing\replacing brake fluid are not the same thing.

[WWWPerfA_ZN0W]

I would service the caliper slide pins first make sure everything is moving freely then go from there w/ regards to the brakes.

 

Instances of a bad brake booster do happen even when relatively new.

[CinnamonEdge]

Push rod needs adjustment on the booster it may be out too much.

[CinnamonEdge]

Brake switch could be bad too

[ldruth61]

The push rod on a 20** edges are not adjustable. 

[David Young]

4 wheel disk brakes are easy to work on. I cant understand how so  many people can't find your problem :(.  Only things I would check or replace would be...….After driving take a temperature gun and find out which caliper or calipers are dragging, the rotor will be hot. When and if found, replace the rubber hose or hoses that connect to the caliper. Air in the lines can cause calipers to drag. If one or several are dragging be sure to grease the pins in the caliper, like others have said.  These are the things I would be doing if I were having a problem like you

Edited March 22, 2020 by David Young