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All four brakes are locking up.

55K views 40 replies 22 participants last post by  Bw4894  
#1 ·
Okay so here's the problem I'm having with my 2002 f250 4x4 diesel. I can drive approximately 4 miles before all 4 of my brakes start locking up to about 50%. I did the Haynes check for the hydro boost before and after the problem (before I drove my truck and after I drove it and made the brakes lock up). And it checked out fine. And when the brakes lock up the pedal gets rock hard.

I just recently got the recall done (the cruise control brake valve or something.) and I called ford and got a typical response saying "that wouldn't cause any of those problems." which I don't believe. And the only other things that change before the problem started was the recal and new power steering pump and gear box.

Please help. I need my truck back up and running tomorrow. Please any help will be good. Thanks in advance.
 
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#2 ·
Really?? Nobody at all has anything? I can hardly believe that this has only happened to me.

Anyways. I have done everything that I can think of except selling the truck. I have new skyjacker extended brake lines for the front since I've narrowed the problem down to the front right wheel. I took the brand new caliper back to AAP and got another new one. I have bled all the brakes 6 times all together. And after I bleed them they work like normal for about a day and a half.

I'm out of ideas. Would someone please help me?
 
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#3 ·
Wow I don't know what to tell you. Um... when it goes tight can you crack the bleeder on the rf wheel and then it goes back to normal?

And btw the recall is only a jumper harness on the cruise deactivation switch on the master cylinder. It has nothing to do with the brakes other than it reads pressure.
 
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#4 ·
Thank you for the reply. Yeah when I get it home and get it jack up the wheel is locked. Crack the bleeder and it spins all day. And about the recall. I wasn't completely listening when I was told what it was for. So I apologize.
 
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#5 ·
If you are cracking the bleeder and it goes away than that says to me that you have a restriction in a line or a hose. You need to get it to lock up again and crack the line at the top of the hose and work your way back to the abs module and then to the master cylinder. When you find the spot where it releases on one end but not on the other then you know where the restriction is. If you pump the brakes does that wheel stay locked up after you release the pedal?
 
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#7 ·
It's not that quick to lock up. I can drive about 6-10 miles before it'll lock up after it sits at night. I haven't tried that line cracking method yet I'll try it in the morning.
 
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#9 ·
I had a brake pushrod that was too long for the master cyl cause a similar problem on a jeep, it would not fully release the brakes when hot and pressure would build until they draged. a slight grind on the brake pushrod cured it on the jeep, maybe aproblem with the hydroboost mster cyl compatability? We diagnosed it by loosening the master cyl bolts to let the brakes release fully.
 
#10 ·
The brakes all worked great before I changed everything on the brakes (except the rotors were shot and same with the pads. The slide pins were even seized up and they worked flawlessly.) so I don't think it'd be the push rod. And I even flushed the PS system thinking that it was something in the hydroboost. It didn't help any. Do you think a brake fluid flush would be a benefit? How much is one? Can I do it my self or is special tools necessary? And if you noticed I'm clueless about the braking system. It's my kryptonite.
 
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#11 ·
So just a little update. I drove my truck into town last night (17 miles) and the brakes started grabbing as I got there. And as I was heading back they were still grabbing but then released after a few miles and I made it the rest of the way home without them grabbing again.
 
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#12 ·
I'd have to agree with the pedal travel, see if you can hook the brake pedal back up when its dragging, maybe its binding, check against the upper stop to see if there's a harness or bundle that's keeping the pedal from returning. When the brake rod is fully extended from the MC, the drain holes open up and all residual pressure comes back up from the pistons, else you'd not be able to squeeze them down to put on new pads. its possible the return hole in the master cyl is plugged with some debris.
 
#13 ·
i had this same issue on an old Full size bronco i had. i had a new master cylinder put in and after that it was the same issue you're describing. it would drive fine but by teh time i got ot work the brakes were locked up. well after having to towed it turned out the master cylinder could not release the pressure. it was totally out of adjustmetn. pull your master cylinder and replace it. i'd never heard of anyone having this issue but me. i ended up researching it and there is screw that sets the pressure in the master cylinder. (I'm an idiot and dont know any of the right terms,) but if the screw is in too far, it can't release the pressure when you take your foot off the brake pedal. if you're in stop and go traffic the pressure will build much quicker. let me know if that makes sense. I'll try and find a picture and explanation.
 
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#34 ·
told ya so! haha, just kidding. i'm glad you got it fixed finally!
 
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#14 ·
Too much fluid ?

ref:Why would your brakes pedal get really hard and the brakes lock up after driving 4 miles

Any time a brake friction component comes into contact with a braking surface, heat is generated. If the shoe or pad generating that heat is not removed from contact with the drum or rotor for an adequate period of time between applications, heat is built up to an excessive level. This creates both a glaze upon the contact surfaces and a boiling condition of the fluid within the brake cylinder or caliper. This boiling increases the pressure exerted upon the braking surfaces further, leading to brake lockup; and, should the brakes be applied, the glazing which has occurred prevents normal friction action from slowing the vehicle as intended. This condition results in more pressure being applied to the service brake pedal in an effort to control the vehicle, which creates yet more heat, and more pressure inside the system. What is felt at the brake pedal is increased resistance due to these factors. This is the 'hard pedal' associated with the condition of 'brake fade'. If a caliper is sticking on its slides, or a brake shoe is adjusted too tightly, the result will be as depicted above. In addition; should the master cylinder be overfilled, not allowing for the expansion of the brake fluid when hot, this can occur. Brake fluid which has absorbed an excess of water will also cause this, due to the lowering of its boiling point by that water; and, since it is hygroscopic, brake fluid can absorb as much as 3% water by volume in a sealed plastic sales bottle in a year's time just through the pores in the plastic. Taken together, these things make it all too clear what can happen when brake systems are left without maintenance monitoring; and, if your car is "right", the car of the guy coming toward you may be faulty in this regard. Be safe; keep a professional eye on the brakes: A short-cut here is a short-cut nobody should take...
 
#15 ·
Not saying that you don't know what you're talking about Johnny. But I just wanna get some more verification about the master cylinder. Cuz I'm unemployed right now and money is really tight and I can't be throwing money at it hoping it'll work. But I personally thought it was something in the MC and the guys at the aps all told me that it couldn't be. So it makes me feel better that someone else agrees.
 
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#16 ·
When was the last time your brake fluid was changed? I had a similar problem that drove me nuts, any time i had to brake hard, my passenger front brakes would start dragging, it would get progressively worse until I stopped and let them get cool to the touch. I changed the caliper, the pads, the rotor, to no avail. Then someone suggested that I change the brake fluid, because, as mentioned above, it absorbs moisture. So I flushed out the whole system with fresh, clean DOT 4 synthetic, and whala! No more dragging brakes.
 
#17 ·
I've never fully changed all the fluid. Just added more when I was bleeding them. Is there a specific way to flush the system and to bleed them?
 
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#18 ·
Start at the right rear caliper. Put a hose on the bleed screw, the other end in a container. Crack the bleed screw open and pump the brakes until you get clean clear fluid out of the caliper. You'll need to monitor the brake fluid level while doing this... let it get too low and you'll suck in air. Once the RR is done, then do LR, then RF, and finally LF. The last three should take considerably less time than the first one since the distance between the MC and calipers should be less.

If you have access to a vacuum bleeder it makes short work of this job since you won't need to have to pump the pedal, you could suck the new fluid through the system.
 
#19 ·
Cool that's what I thought I just wanted to make sure. I just picked up valvoline dot 3&4 synthetic brake fluid and a vacuum pump. And when my new stainless brake line for the rear get here tomorrow I'll be doing all this. I hope it works. I'll let y'all know what happens.
 
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#20 ·
Probably not what your trouble is but a deteriorating rubber brake hose can allow a swelling in the rubber line when the pedal is pushed. When released it can cause the caliper not to release because of the pressure from the swelling...like a ballon releasing towards the caliper. But it usually only cause a longer than usual grab on the brakes and then will release after a minute or less. Can cause a freaky pull to one side after a stop light but thats just one brake line holding pressure after the pedal is released. It sounds like you are having a similar sort of pressure problem...maybe the proportioning valve is sticking somehow?
 
#21 ·
I'll just throw this out there as a diagnostic step - when the brakes begin to fail to release, are the brakes lights on? If yes, this would be an indicator that the pedal is applying pressure. This could be caused by the brake pedal return spring having broke, has become weak or the pedal pivot is binding. Without reading this entire sting again, you mention you replaced the entire brake system. What was actually replaced? If you only replaced the mechanical components, i.e. not the calipers or master cylinder, I would look closely for the brakes pads binding in the caliper bracket. These areas should be cleaned and lubed during reassembly. Did you closely match component for component when you replaced. Incorrect size brake disc, pads etc can cause all sorts of strange things.

sflippen provided a great explanation of the effects of friction/heat. But you need to find root cause and for that, you need to start with the basics i.e. back at the beginning.

Well that's my 2 cents and 30+ years of wrenching on import cars. And yes, my wife has an 02 F-250 which just turned 50,000 miles. Yes, that was 50k miles. She only uses it to pull her horse trailers.
 
#22 ·
Just want to share this info with you. A few years ago my friend had a Chevy Tahoe that had a hydro-boost system that was doing exactly what you are describing. He brought it to me and what I found was contaminiated brake fluid. I did not have the fluid analyzed in a lab but it looked to me like somebody put anti-freeze in the master cylinder. I had to flush all the steel lines, replace all the rubber lines. Replace the all the calipers and the master cylinder. After doing this all was back to normal. What happened to us was the contaminated fluid broke down the rubber lines and caused a restriction in the calipers. Don't know if that is your problem, but it may be worth having your fluid checked.
 
#23 ·
In the beginning he stated that he replaced the powerstearing pump and stearing box. Did you flush out the lines before re-filling the new pump? The stearing pump also works the Hydroboost. Trash in the line could have gummed up the hydrobooster. I've adapted hydroboost to several non-diesel cars. Never had this kind of a problem. Just my 5 cents worth. I hope I did this right. It's my first time trying to help. If i did it wrong, please let me know. Thanks
 
#24 ·
if you recently had caliper slide pins out did you use anything other than silicone grease to lube them when going back? my '02 had orings on slide pins and i first used white lithium to lube. it wasn't long before they were dragging. pulled 'em out cleaned up and used silicone GREASE - no more problems.
 
#25 ·
All four brakes are locking up

Hello,

Not sure if you have fixed or resolved the brake problem.
I have a 06 F350 SRW Crew 4X4

I had the same problem but first it was the rear and then the front.
I changed out all the rotors and calipers myself. New pads, etc.

Brakes work better than before. Its a drastic measure I know,
but stoppin' these things safely is critical.

Good Luck
 
#26 ·
Okay so I got my new stainless extended brake line for the rear yesterday and put it and then flushed the whole system with the synthetic dot 3&4. And it's still doing it. Should I try the proportioning valve or the MC next?
 
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