Abs overreacting

[Ella]

Hey everyone! I have a 2006 e-350 ford school bus and every time I break when the bus comes to a complete stop the brake pedal judders and makes a whining sound. I’ve had it to a mechanic who says all the breaks are in good shape and that it’s more likely it’s the abs system that is over reacting. He says it’s fine to drive this way but if it annoys me he can disconnect the abs and the brakes will still work fine.
He also said it is impossible to find a new abs system to replace the old one because of the year of the bus.
Does anyone else have this issue? What are your thoughts on this?
I do trust my mechanic, he’s been working in big diesel trucks and buses a long time, Howe It’s important to me (and the rest of the world;) that the breaks work. So I wanted to get as many opinions on this as possible.

[Booyah45828]

Bad speed sensor giving a weak signal that looks like a locked up wheel to the abs system at low speeds. Using an obd2 scanner with a graphing feature you can slowly accelerate and then slowly come to a stop and see which wheel speed sensor drops in and out compared to the others. I've fixed this on several vehicles.

[cadillackid]

my IH did that.. I had a faulty wheel speed sensor that would indicate one of the wheels was slipping even though it wasnt... more often than not I seem to run into ABS problems as being with the wheel speed sensors either getting metallic brake material on them or the "tone ring" on the rotor gets greasy from an axle leak or such and picks up metallic material from the brake pads as they wear..

[Ella]

Thanks for the reply. Do you know if it is safe to drive the vehicle with this issue? I wonder why my mechanic did not check the wheel sensors? Do all mechanics have an obd2 scanner?

[cadillackid]

all good mechanics these days should have a scanner.. like booyah says they can watch the data live.. on a van chassis it shouldnt be hard for them to do..



on my IH I had to run a special program but still was able to do it.. if you feel like the vehicle is over-reacting often then you can pull the ABS fuse until you get a chance to look at it.. it would operate with the ABS light on and possibky check engine but can be driven.. albeit with no ABS function.

[Booyah45828]

It's safe to drive cautiously. The hydraulic components of the braking system are still intact and solid, it's just your braking ability will be diminished at the end of every stop. So I'd avoid bumper to bumper traffic. You can pull the abs fuse for the time being to eliminate the activation, but I'd only do it temporarily. ABS is a nice feature to have. It is worthless in snow and ice, but panic stopping on the interstate it is super helpful at preventing wheel lock and accidents.

With that said, I don't know what your mechanic saw. Maybe the ecu has failed and is causing your problems. My suggestion was based off of your symptoms and me having experience fixing vehicles with that identical symptom.

Your abs unit has an ecu and intelligent diagnostics, so checking for codes would be step 1 for me. If nothing comes up as wrong, and everything seems to be working correctly, I would then go through and see which speed sensor is weak/dropping out on a test drive.

[Ella]

Thanks so much. This is super helpful❤️

[Mat7783]

I just replaced left rear abs sensor on my 2000 Thomas bus.I have a EC-30 abs controller that shows the led fault status which I found after we measured all sensors and found this one out of tolerance.did you check to see if your abs controller has indicators?