2001 F-250 Crew cab, 7.3, Automatic with cruise control. 118k, automatic

Hello,

It all started when my front drivers side caliper froze up. I've replaced about every wheel caliper at least once. Problem is I don't drive it enough. Only 3k a year.

It's the last 1/8 of the caliper cylinder that rusts due to air/salt exposure, expands, and locks the piston.

So, I replaced the caliper. Then, I was bleeding the brakes and the pedal would not hold... Found that a brake line was cracked in the rear. Replaced that. Bled the brakes again. The pedal would still not hold.

Today I replaced the master cylinder. Probably due for a new one, but it did not resolve the problem. Pedal still goes toward the floor. If I pump it up it will rise, and hold while under pressure. But, if I let up and drive a minute or so and hit the pedal again, down toward the floor.

Am I missing something about the brake system on this F250?

Tomorrow I will push another quart of brake fluid through the system trying to find some air.

Any ideas welcome.

Regards,

redbug

 

Did you follow procedures for filling the master cylinder or install it right out of the box. When bleeding I always start with the rear passenger tire as it’s the farthest from the MC then rear driver front passenger front drivers. The dot3/4 synthetic fluid is pretty cheap as it seems like additional bleeding is needed. Worst case a vacuum bleed should finish it up. I just had to use that my self on the hydro boost as it sat open for about 6 days and pumping gallons of trans fluid through the system wouldn't get all the air out. Hit it with the vacuum a few times (should have been once but the mighty vac kit doesn’t have the best seals straight out of the box. My brakes were only affected slightly by the bleed and only on the initial one which was the weakest vaccum as I hadn’t upgraded my new tool yet. However there are several adapters for brakes that come in the kit and one for the M/C.
Are the brakes working at all or not doing anything when you say all the way to the floor?

 

I also just did 3 calipers 2 less than 10,000 one at about 35,000 the 4th seems original go figure all had lockup issues from sitting for 3 weeks. Next time I’m going back to morotcraft there just wasn’t time rock auto has the motor craft calipers loaded with pads for 99 if these go out again

 

Just finished up about a month ago, with same symptom in friends' truck(01cclb 4wd)...3 masters, 2 hydroboost, clean slide pins and 1 psp.... Brakes worked great unless at a stop light/sign. Pedal would go to the floor. Ended up being, that it needed a new ABS module

 

Yup if you aint got the tool capable opening the valves on the ABS your never going to have functioning brakes, this happend to me with my Wifes Excursion from when I swapped the 4.30 diff had to take it to an auto shop as my AE doesnt havw this feature or I didnt know how to use it lol..

 

The brakes are working but first time in pedal is close to the floor. A new ABS module....?

Are the ABS sensors light sensitive? I treated the rust near the sensor, I wonder if paint got on it? I attempted to steer clear of the sensor. That might explain it. Can the ABS system be switch off to test?





This all started with a stuck caliper, now everything is failing at once...

 

an abs sensor won't cause a spongy pedal. It sounds like there is still air in the system. Put some brake fluid in a water bottle or glass jar (fill it about 1/4 of the way) put a hose on the bleeder valve and open the bleeder with the hose submerged. Pump the brakes repeatedly. You will see air bubbles, but you can't suck air back in with the hose submerged. Do them in the order suggested above.

if the master cylinder wasn't bled good enough, you very well may have air in the abs module, which requires a computer to cycle the valves to get the air out.

this is how I did the brakes on my excursion when I had it and I replaced everything at once. With as much stuff as you replaced, there was lots of opportunity for air.

 

IIRC, you should be able to control the abs module with forscan

 

Redbug..

https://www.ford-trucks.com/forums/1...onclusion.html

 

I dare you to buy the ABS module then introduce more air into the system then have the pedal stay the same you already said you don’t have the software to have the ABS pump Pulse.... bleed the damn system with the vacuum (35-40 little more for a craftsman brand) start cheap then increase your cash blessings for the truck. As I did not see the ABS light is indicating on the dash reported. You have a simple physics problem here air is compressible hydraulic fluid does not and leaks in the system have been repaired.

 

Going to side with those saying you have a leak or air in your brake system. Bleed the system by the book... tube into a bottle of fluid... until no more air bubbles come through.

 

Buddy had no ABS light on, either 😉

 

Hooked up my code computer to the truck. It did not have a bleed maintenance menu option but when I analyzed the brakes I could hear a grumbling under the hood. So, I gathered that was the ABS cycling. Got under the truck again and a bunch of air blurted out of the rear calipers.

So, yes, there was still air in the system. Did the computer bring it out? I'm not sure but I think it did.

Brakes are back where they should be.

Thanks to everyone for their help.

Regards,

Redbug