s5150stang

I have a 2004 XLT SCrew and about two weeks ago I changed the brakes on the front. No problems this time. Two years ago I found one piston on either side cracked and leaking I was not happy.....and of course Ford shoved one in me and made me eat the cost.

Not thier problem!

Any rate I have no problems but know the rears are bad and need changed also. A few days ago I hit the brakes and they go soft and to the floor. I blead everything when I did the fronts and had no problem. So I figure it is definatly time for the rears to get replaced.....

I put the rears on and have blead them five times now! And still the brake pedle is soft one time and nice and firm another...or not... I have changed brakes for many years and never had a problem like this so I dont believe it was how I blead them.

I read about the recall on the 2005's but no 2004's. Ran my VIN at Fords site and no recalls at all?

Good old Bill

Trying to understand what has been said. Irregular brake pedal feel points toward master cylinder. At a stop and holding the brakes on, does the pedal seem to go to the floor and eventually the truck creeps forward. This is a sign of a master cylinder bypassing the fluid pressure.

Dark Stone

My first thought was the master cylinder as well.

Mod (Ret.)

Could be the master cylinder, but before I'd make any other assumptions, I'll assume you are not loosing any brake fluid, correct? I'd first go with air in the system. Whenever the brake system is opened up (I.E. removal of a brake line, removal of a caliper or wheel cylinder), air will enter the system and COMPLETE bleeding is required. The rule of bleeding is that you start with the FURTHEST point from the master cylinder, bleed that point, then move to the next furthest, ending up with the closest point to the master cylinder. On your truck, this would be: 1) passenger side rear 2) drivers side rear 3) Passenger side front 4) Drivers side front. From your post, you stated you bled the system 5 times already. What method did you use to bleed?

If you are bleeding using the "buddy" method (friend pumps brake pedal then holds down brake pedal, you open bleeder valve, pedal sinks to floor, you close bleeder valve, friend pumps pedal again and proccess is repeated until no air/bubbles are seen at that wheel), be aware that this method may take 2 to 3 time to completely remove the air from the brake system. I personally prefer the "mightyvac" tool; it allows this proccess to be a one man operation, and works using vacuum to suck the brake fluid at the valve. You still start at the furthest point and work towards the closest, but the vacuum method is much more efficent. It goes without saying that after each wheel is bled, check and top off the master cylinder resevior with clean brake fluid.

It may be the master cylinder, but when they fail, they usually do not allow you to pump the pedal and get pressure; they simply allow the pedal to sink to the floor each time the brake is applied. Your description sounds like you have an air bubble in the system. Try bleeding once again before you buy or replace the master cylinder.

I assume you have 4 wheel disc brakes? These are easy to work with compared to drum brakes; I dislike replacing the wheel cylinders with the springs, adjusters, and the like. God bless the inventor of disc brakes!

s5150stang

No it will not do this. If I hold it down it stays for the most part and the truck will not move. I was off road a but on sunday and had no problems other than a soft irregular pedal. I dont believe it is the master cylinder.....YET!

I did drive it today after bleeding them again last night. Seems a little bit better but I am not sold. I may just have a ton of air in the lines somehow.

Still love the truck. Had a 98 and had problems with the 4.6. Got this one with 5.4 and love it. Also did not think I would like the 4 doors. My family loves it. Still hauls a ton of sand and then some. Still hauls ***. My buddies at work are all turning to Toyota..... Retards! I will keep my Ford!

Good old Bill

Please don't misunderstand me, I'm on your side. Don't know how to copy the sentence about "hit the brakes, felt soft and went to the floor". As I understand, front brakes done a couple weeks earlier and everything was working fine and then on a stop the soft pedal occured. I am convinced, you and your ability is not the issue. During a routine brake pad or linning change it is impossible to have air enter the system. If the hydraulic portion of the system wasn't touched then it was not compromised. If brake fluid is heated to boiling it will break down and thus we have air in the system. We both know this did not happen. Maybe this book that I have just written will trigger someone to chime in and put me in my place. Or at best, give us some other ideas.

Mod (Ret.)

It's possible the pads got too thin. If the pads were worn down significantly, and the piston/pistons were out further in their bores to compensate for the worn pads, then yes, air could have entered around the flat "O" ring seals of the pistons. Usually a "C" clamp is used to compress the piston back into its bore, and if the piston is cocked slightly, this to could allow air to squeeze past the piston/bore seal.

I do agree with you though that the pads are changed before they get to this extreem point of wear in most cases; I could never convince my son to periododically inspect his pads! He actually got down to the metal rivets (that held the pads on their backing plate) grinding into the rotors. They of course had to be replaced too.

s5150stang

[quote=Bucko;106315]It's possible the pads got too thin. If the pads were worn down significantly.....

I do agree with you though that the pads are changed before they get to this extreme point of wear in most cases.....

OKay! I am guilty of that. I did let both sets go down pretty. The front to the point of grind and the rears pretty close. I knew they where bad and just procrastinated. Then I do not drive the truck everyday to work. I usually only drive it once a week. At $2.55 a gal. here its still hurts at the pump. My wife drives it to take the kids to school a shorter distance away. Aprox. 2mi a day. Do you think that she noticed the hair raising grind in the front brakes???

Anyway drove it today and she was still not consistant. One time nice and firm the second time nearly to the floor. Every time no problems stopping. I did hold it down and pushed hard to see if I could make it bypass the master cylinder or atleast break the damb thing to be sure it was it. She held where she was.

Mod (Ret.)

These symptoms describe air in the system. You have a "bubble" of air.

At this point I'd purchase a "mightvac" tool (cheap; can be bought at any decent auto parts store like Pep Boys), or take the truck to a shop and have them use a power bleed system.

But by all means, don't drive the truck regularly until you get the brakes fixed! God forbid you need to make a panic stop because a kid ran out in front of you.....