I currently have a 01 expedition xlt 4.6 and recently I came across the spongy brake issue so i replaced the abs pump with one from the junkyard and bled the brakes, for at least a week it was driving fine i did notice the parking brake was a bit stiff when id push it down. Then one night while driving i tried braking and there was a loud rattling from what felt under the car and then the right rear wheel brake locked up and would not disengage. I tried everything online to disengage the brakes and found out it disengaged when i would put the car in reverse, while in reverse the car brakes and drives fine but when i put it in drive and push on the brake the loud rattling happens and the brake engages (only right rear wheel) . I used FORScan to see if there was a abs code but none came up, Not sure really where to go from here I think it might be the emergency brake engaging but i don't know, any insight would be greatly appreciated, thanks.

Update 6/6/24: I recently replaced the ebrake shoes and even removed them but I still have the same issue. I've been looking online to see what can be the cause but I'm stumped. I'm thinking the next step would be to replace the abs pump but I'm not confident that's the issue due to it not reading me any codes and the fact that the brake pedal feels normal and the car brakes fine in reverse. I'd greatly appreciate any suggestions.

 

The e-brake shoes broke loose and are jamming against the e-brake drum when driving forward.

 

Thanks for the reply I’ll be checking that today.

 

I changed the brake shoes and even completely removed them but it still has not fixed my problem. I've been looking online to see what can be the cause but I'm stumped. I'm thinking the next step would be to replace the abs pump but I'm not confident that's the issue due to it not reading me any codes and the fact that the brake pedal feels normal and the car brakes fine in reverse. I'd greatly appreciate any suggestions.

 

Wow I'm surprised, I'm sorry that didn't fix the problem, I really thought it would. I did have a similar issue on a different vehicle one time many many years ago. A bolt inside the rear differential had come loose and got jammed between the ring gear and the bottom of the case. It was in such a position that when the vehicle was driven forward it would jam the bolt tighter between the ring gear and the case, but when going in reverse it unjammed the bolt. I'm hard-pressed to believe it is the ABS pump. If the pump motor was running I could understand it applying pressure in the brake line and locking up the brake, but that's not what's happening. If you think there's a chance brake pressure is the root cause, you could always try cracking the bleeder screw loose and seeing if the vehicle will drive forward, knowing that there's no pressure in the line. Of course be ready with the e-brake to stop you since the regular brakes will likely not.

 

I appreciate the reply and the help, I doubt it’s the abs pump as well but it’s the only thing I recently changed besides front suspension parts. I’ll be checking the differential and drive shaft. I tried to attach a video of the sound but it’s to big a file. The car in drive drives fine but the second I push the brake pedal the rumbling starts and the wheel locks. I have a lot of love for my expy it is my first car and I’ve been putting lots of work into it and I don’t want to scrap it.

 

Did you purge air from the replacement ABS unit, not just bleeding the brakes? Forscan can manually activate it.

You will probably have to rebleed