I purchased this truck last November used. It had been well maintained and had all of the maintenance records. 110,000 miles when I bought it. at the time of purchase I was towing a small 28 ft travel trailer and noticed that the brakes did not seem up to par. I just purchased a 5th wheel trailer that weighs 9000 lbs loaded. I took the truck in to have the brakes looked at and the ford dealership turned all 4 rotors and installed heavy duty commercial brake pads. after picking up the truck and on the way home I noticed when making a quick stop that the pedal went almost all of the way to the floor and I had to pump the brakes to get full pedal. I took the truck back the next day and told the service writer that there was still something wrong with the brakes. He had me pump the brakes and put pressure on them to see if there was leaking fluid. There was none. I had him get in the truck and press on the brakes pedal and when he did it went almost to the floor. within 1 inch. He said that he heard a noise coming from the brake booster and that it may have a air leak. He said that it would take 35 40 minutes to check it out. 45 minutes later he came and said that it needs a new brake booster unit. I just spent over $450 for a brake job and now they tell me that I need a brake booster for another almost $500. This truck is only 7 years old and only has 118,000 miles on it. They claimed to have done a road test and complete brake inspection when the turned the rotor and installed new pads. Today I bleed the brakes and changed brake fluid and I now have almost full pedal. I am starting to have reservations about them changing the brake booster. on the other hand I will be leaving for home 850 miles at the end of the month towing my 5th wheel. Any thoughts or advise would be appreciated.
Mel

 

drive it HARD (braking).... to test brakes a few more times..

a closed system... seals and one speck of dirt at the master cylinder.. temporary failure/leak of pressure.. intermittent booster issue...

See.. a part of the system (repair shop)... you drive it all the time.. a mechanic might get to drive it for 2 miles..
also.... if they just PUSHED the calipers back in... dirt is pushed up to master cylinder...
I push the caliper piston back in with the bleed valve open.. so NO old fluid is pushed UP.. it goes out the bleed...
and then after the brakes are finished.. I fill up the master cylinder

my opinion, retired mechanic ( not Ford )

 

They haven't bled the system correctly. they got air in the system somehow. Let the truck sit for a day, that will let the air rise to the top of the caliper. then just press on the peddle with the bleeder screw open. Don't pump them up first. You don't want to mix the air back into the fluid. Just press on the brake with the valve open till the fluid comes out. If peddle goes all the way to the floor and no fluid comes out than close valve and do it again. Make sure you don't run the reservoir dry. If master cylinder is bad than peddle will slowly go to the floor once the brakes are applied. You will get a hard peddle then it will slowly bleed off pressure and peddle will go to the floor.

 

How about the trailer brakes on the first travel trailer? Were they adjusted properly and the brake controller set properly?

 

Yes the trailer brakes were properly adjusted before I went on a trip. the Travel Trailer was a 2017 and I put 900 miles on it. The trailer brakes were not the problem. Driving the truck without the trailer produced the same problems with braking. I will not drive a vehicle towing any trailer unless the brake system is working properly... This is the reason I took the truck to a Ford Dealerships service dept. I figured they should know what they were doing to restore the brakes on my truck to like new condition. I am starting to have my doubts.
Mel

 

Here is the symptoms and what has been done so far to resolve the brake problem. When driving along and doing a normal stop I notice the pedal goes almost to the floor before the brakes grab hold. I have to pump the brakes to get a firm pedal. some times when pressing on the brake pedal it will pulse like a bad pad or rotor. when doing a panic stop, the pedal went almost all of the way to the floor within one inch no time to pump the pedal. I barely got stopped in time to keep from rear ending another truck who did a panic stop in the middle of the road. I took the truck to the Ford garage and told them to fix the brakes. I also told them I wanted new heavy duty brake pads and the rotors turned. this is what has been done so far. The brake pads were replaced with Wagner Commercial Severe pads.
all 4 rotors were turned.
I changed brake fluid and bled the brakes twice since getting it from ford. Since bleeding the brakes I have more pedal, but still not like it should be and I can pump up the brakes to get more pedal. When bleeding the brakes only one caliper had air in it and that was the right front. That was how I got more pedal. Correct me if I am wrong. Since the brakes are 4 wheel Disc there is no adjustment. That leaves Brake booster, master cylinder, and possibly Caliper. I figure it can't be master cylinder because with steady pressure the pedal does not bleed down. That leaves the Brake Booster or maybe a Caliper. It is hard for me to believe that it is a brake booster on a truck 7 years old and 118,000 miles. The brakes are working much better since the pads and rotors were done and I bled the brakes. My only concern is having to pump up the brakes which ford says is the brake booster. Guess I am a doubting thomas. Please any Ideas or comments. If it needs a new brake booster then I will have them do it. I just don't want to spend for something if it is not needed. to many of the Garages here in Yuma AZ are crooked and take advantage OF SENIOR CITIZENS. Thanks for your time and comments. I have to leave for home almost 900 miles pulling my 5th wheel trailer and want to have good brakes on the truck. The trailer brakes and controller have been inspected and ARE IN GOOD SHAPE.
Mel
Mel

 

There is another possibility. That right front caliper might have a cracked hard line or torn flexuble line.

 

needing to pump the brakes.. and the pedal does go up and holds.... that is Air in the line.... period... it is trapped... in a bend...

may need to do vacuum or high pressure bleed....

I prefer a vacuum bleed system...

I also Bleed.. with the Front of the vehicle lower then the rear... to help air bubble to go to rear...
as the LONG Lines from front to rear are more likely to get a trapped air bubble.

 

 

If that was the case then it should leak Brake fluid when pressure is applied. It does not leak brake fluid anywhere. The master cylinder stays full unless bleeding the brakes.
Mel

 

Yes the bleeders are on the top.
Mel

 

My question for everyone who has commented and replied, Could it be the Brake booster Given all of the symptoms that I have described? I lean toward air in the line,but could the brake booster cause the same problem as described?
Mel

 

No, the booster could not cause the symptoms. It sounds like the MC is the issue.

 

If it was the master cylinder would not the pedal sink when holding it with pressure after pumping the pedal? I did a little test today. I took a long drive and pressed the brake pedal like you would do normally. The pedal went down to about 3 inches from the floor and it was solid did not go down any further. at that point the breaks would bring me to a full stop. I did the same thing at different speeds and pedal pressure. the brakes work and stop the truck but the pedal goes down to within 3 inches of the floor before any breaking occurs. I can get a little more pedal by pumping the breaks but not much. it appears like the booster is not working correctly. The brakes are not spongy. I am at a loss. no way for me to check the brake booster. I have made up my mind that I will drive the truck home almost 900 miles and do any work myself including a brake booster. I can buy a booster for $69 and install it myself which is better than $500 to the ford garage. I don't trust them after they said they did a complete road test and inspection. I have a Garage that has all of the tools and Equipment to do any job at home.
Mel

 

You most likely need a new master cylinder. You could try adjusting the pushrod from the booster to the master cylinder a LITTLE bit at a time, just pull the nuts off of the mounting studs and pull the cylinder ahead, adjust the rod maybe a half turn remembering where you started, and put it back together and test drive it, if it is better you could adjust a little more but if you go too far the brakes will start to drag and not release, if that happens just back off the adjustment a quarter turn at a time. If adjusting the push rod doesn't help return to the starting point and replace the master cylinder. The booster can not give you a low pedal, just a hard pedal from lack of power boost. One possibility is that over time crud built up behind the piston, in the process of bleeding you loosened some crud in the master cylinder and now the piston is not returning all the way to the at rest position