A few key points I need to make:

1) No or weak vacuum to the booster will make the pedal HARD to press, the boost will be gone. It doesn't make the pedal go any lower than it usually does.

2) I've never seen a vacuum booster go bad in such a way that the pedal goes down too far except if it wasn't adjusted right during installation, and then it would be all the time. Their job is to boost the power applied to the pedal. There is a definitely mechanical relationship between applying foot pressure, and the pressure applied to the master cylinder, and there's is almost no way the booster can cause the pedal to go down as far as you're describing, and almost definitely NOT intermittently. At least, that's the way vacuum boosters have always worked, unless something "new" has come out in recent years and I'm talking out my butt.

After all the work you've had done, this all sounds like the TYPICAL anti-lock brake valve body leaking internally. I'm not sure about the 2008's, but up until 2004 at least, the Kelsey-Hayes anti-lock braking system used valves that would open and dump pressure into "accumulators" when you need anti-lock activation.

The typical failure of the valve body is that the pressure-release valves (that are actuated electronically) leak into the accumulators. Usually because of crud in the system.

What happens is - every time you start the vehicle, the system resets itself - it activates all the valves, and runs the pump. If there is a leaky valve because of a piece of crud, it may leak intermittently, which is why every time you start it, it may or may NOT act as you describe.

What I would do is take the truck to a dirt lot or somewhere else with low traction. Work the ABS unit a bit by getting some speed and slamming on the brakes. See if it clears up or even gets worse. If it does get better, do NOT rely on that - get the system flushed.

The Ford dealer should be able to bleed the system fairly easily - they can hook up the diagnostics computer, and exercise the system, turning on the ABS pump, and opening each valve one by one, and opening the bleed nipples and flush the entire system.

On top of that, there is a faily easy way to diagnose leaky valves in the Kelsey-Hayes system, but it's a bit tough to get to on the F-series - it's up on top of the chassis rail on the driver's side in front of the plastic wheel well.


Again, I know the Kelsey-Hayes system was used up until at least 2004 when I stopped paying attention to the systems in the newer trucks. I can't imagine that even if they went with a whole different system that it doesn't act the same way.

 

This also is a good point.

 

Thanks for the reply guys... here is something I found from wagner that sounds very close to what I am experiencing. Maybe i should give this to the service techs at the garage... hahha.. What do you guys think?

http://aftermarket.federalmogul.com/...ng%20Pedal.pdf

Thanks for the additional information.

Jim

 

I believe this is exactly what Krewat was talking about. You may be on to something.

 

Update: Imagine that, now the dealer says the hydraulic control unit (I assume ABS, because he never totally told me) is bad. another 900 bucks plus labor. I love this truck, and quite honestly, if I didn't it would be gone. This is the first ford truck I have owned (3 Silverado's in the past) and never had these issues at 25,000 miles. I wouldn't have minded spending 900 bucks on a HCU if they would have determined that was the problem from the get go instead of throwing everything under the sun on the truck praying something would have fixed the issue. They aren't working with me even though they screwed the pooch with the diagnosis. I specifically told the service manager that if brakes, rotors, calipers would fix the problem then do it because it had to be done (I could have done it myself but it was already there). And I still cant get over the fact that they inspected it in January and I bought it in February and they found all these brake issues.... I gather they were not spending any money on the truck before resale. What a joke. Im done with this ******* dealership.


I would like to thank everyone for the advise and please don't take this post in any other fashion than I am extremely pissed right now.


Thank You,


Jim

 

Jim, I really feel for you man.. Sorry that we weren't able to zero in on the problem, but braking systems these days are extremely complex as you've found..

If I were you, I would call or PM Crystal user ID= FordService. She has helped a LOT of people here...

Here is more info from her biography page:

Biography
Social Media Team for Ford Motor Company’s Customer Care division - our primary goal is to help community members find the solutions they are looking for. Phone: 800.392.FORD (800.392.3673)

 

Bigfoot: I have contacted Crystal and she has put light on the subject. You guys were a great help and through the whole process I have learned a lot about the brake system on my truck. There just aren't things I can get around through this whole thing. I made it perfectly clear from the get go that this was an issue that occurred after the ABS violently kicked in going down a wet surface that had some potholes. The work they performed with the brake pads, rotors, calipers etc was sacrificial to the real problem and I told the service manager that if he could guarantee me that fixing those things (that I could have done myself and would have preferred to BTW) would fix the problem, then do it because its already there. Why would they put the factory master cylinder back on after I put the Raybestos master cylinder back on? (Am I not competent enough to bench bleed a master cylinder and vacuum the lines?). Why did they tell me the problem was corrected, I go to the dealership and pay my bill, and when I leave the parking lot the brakes were the same as previously described? Why didn't they call me to give me an update? I had to call them every day. And when I called today and then they told me the hydraulic unit was bad why did they tell me that they replaced another caliper??? They said they looked at all of the calipers and so forth when they changed the brake lining. Why when they inspected the truck in January (and I bought it in February) weren't these brake/caliper/rotor issues identified? Because they didn't want to spend any money before resale. Not only that, these are things that could have compromised my family's well being. Last but not least, why didn't they positively identify the issue before stooping to the level of a junkyard mechanic (swap parts till we find the issue) mentality? I work in the service industry (cable as a matter of fact) and troubleshooting and divide and conquer is the first thing I teach a new or experienced employee in training. Math is the other thing. If numbers or levels go up and down people understand how signal in this case (or fluid, or pressure, or vacuum) increase or decrease because of active or passive devices in the circuit. If my technicians were to troubleshoot in this fashion they would be corrected once and if it happened again they would be gone because they are affecting the integrity of my company not the bottom line. Oh, another thing I just thought of? An ABS control unit going bad at 25,000??? seriously??? I know Im ranting on and on and on but this is positively the worst experience I have ever had in a vehicle purchase. And its great to know that you guys know how im feeling and sympathize but also understand the importance of trust in the people working on your vehicle. Once again thank you all for your concern and advise and I appreciate it all.


Thank You,


Jim

 

Update: Garage order new Hydraulic Contol Unit, installed it, brakes still didnt work. Said the motor in the hydraulic control unit was bad. This is a total nightmare.

Jim

 

Jim, there is NO FREAKING WAY they can expect you to pay for all the parts they are SHOT-GUNNING at this truck... These guys haven't a clue what they are doing! Crystal - Please help Jim!!!!

 

I just had the same problem...Frozen wheel caliper, but that should have been one of the FIRST thinks checked, but I didn't see that in this thread...Did I miss it?

Sorry...I should have read closer,,,,

 

Bigfoot: I wish someone or Ford would step up. Ultimately the service department at the dealership screwed the pooch. If it were properly diagnosed I wouldnt even have had a 700.00 bill for parts/labor that werent the cause of the issue. With that being said, who has ever heard of a ABS unit going bad at 25,000? Well, I guess its more often than I think because the one they ordered the other day came in and it was shot right from the get go. Either way, if they didnt do all the unnecessary work (brakes, rotors etc) that they did first, a bill of 1000 for the ABS unit and labor wouldnt be that big of a deal. I thought i got a pretty good deal on the truck (2008 F250 super duty crew cab thats was immaculately maintained, garage kept and locally owned) for 25,700. Now I will have stuck 2000.00 into this thing within the first 3500 miles of owning it. Not to mention that, tonight is 2 solid weeks at the dealership with no results. If i didnt have a company vehicle i would have been screwed. The company i work for has a fleet of roughly 65 F550 Super Duty Bucket Trucks and probably 100 Ford Fleet Vans. Our leases are coming to end so im just sayin.... Unfortunately the chances of me owning another ford are slim and none because my wife (who is a teacher and very rarely gets upset) said we arent ever buying a ford again unless someone makes good for all the nonsense that was done. And the salesman at the dealership (friend of mine that i graduated and played sports with) said he would have the GM call me because he doesnt like unhappy customers. That was like Tuesday or Wednesday last week. Still didnt hear anything. We'll see where this goes, but my guess is nowhere. I may, depending on what happens, notify the local papers and TV stations of the event and how I was treated. If anything, maybe just maybe it will inspire the dealership to properly train their technicians.

Thanks for all of the help guys!

Jim

 

I know it's frustrating that even the dealership can't figure this out, but take a minute and consider the possibilities before completely throwing the dealer under the bus.

A nearly 7 year old truck with only 18,000 miles means it was sitting around a lot. Sitting is worse for many things than getting used. This is probably why the caliper pins were frozen. That may not have fixed the problem at hand, but nonetheless it was something that needed to be fixed.

Perhaps the previous owner did something that allowed air, moisture and/or other contaminants to enter the brake system. This can screw a lot of things up, especially in a complex ABS system. If the truck did a lot of sitting around after getting moisture in the system, this would make things even worse because you would have parts inside the brake system starting to rust. Who knows, maybe he thought the brake fluid needed topping off and used a bottle of fluid that's been sitting open in his garage for 20 years, or maybe he mistakenly put in something other than brake fluid. Maybe he left the cap off the MC and didn't notice it for a year. Something like this happens, and you could have all kinds of stuff that needs to be replaced, but the dealer can only fix one thing at a time.

Maybe the dealer is a complete failure, or maybe you have a very complex situation and they're just doing the best they can.

Sent from my HTC ONE using IB AutoGroup

 

I dont really know how to respond to the last post. The facts are the facts. I haven't thrown the dealer under the bus, they threw themselves under the bus. I merely stated the facts. And they're pretty simple. I took a truck (regardless of the little miles it had) to the dealer for service on the brake system because one time you had PERFECT brakes, the next time NO brakes (pedal right to the floor without any resistance). Brakes, rotors, calipers, air in the system would not cause that scenario. And as I said previously, if they would have diagnosed it properly the first day it was there, they would have known it was the hydraulic control unit. SIMPLE. Instead they threw parts at it with no success. Why exactly did they remove the master cylinder i installed and put the old one back on? Some of these things just dont make sense. If i had the time, and i wanted to throw the dealer under the bus, i could give you another current example of their incompetency with a brand new vehicle and brake issues. And if they were that concerned with how I feel about the subject, why hasn't the GM called me as the salesman said he would?

 

Heres another update: Service manager called me today and said they switched the ABS Unit (Hydraulic Control Unit???) and said that he left the lot and had perfect brakes and when he came back to the shop there were no brakes.... Go figure.. still no results. 17 days without this vehicle now.

 

These braking systems aren't rocket-science. If they did a complete bleed, including the ABS system, then there wouldn't be moisture or crud in the system anymore.

The "hydraulic control unit" is the valve system I was talking about earlier. If it's still the Kelsey-Hayes system, diagnosing them is not difficult. The "brake module" might be the electronics that bolts onto the hydraulic control module.

I really don't know what to tell you at this point, calling Ford's customer service 800 number might be the way to go at this point.