Feels like ABS is kicking on...

Zaairman · Dec 23, 2012

My truck has started this new trick where occasionally after starting it up, driving a few hundred feet and making a turn, when I hit the brake pedal, it feels like ABS is kicking in and the pedal is hard to push and the brakes don't kick in like they should. Problem is, my truck does not have 4 wheel ABS. The brakes always end up working after I give them a pump, but there is still that quick second of "oh sh!t" when the brakes don't work right away. Power steering and brake fluid levels are fine, PS fluid is maybe 5000 miles old, brake fluid is 3 years old, no brake work since then. No calipers appear to be dragging. Brakes still work fine usually. Just after a start and get moving, the pedal will do this only once. Any ideas?

jngreen · Dec 23, 2012

My old truck would do that sometimes when it rained. It scares the crap out of you. I would check the wires running to and the connector/sensor in the rear differential housing. My abs light would flicker on and off though when it had these symptoms.

Zaairman · Dec 24, 2012

Which sensor, the speed sensor in the rear end? That's only a few months old, maybe 1000 miles, brand new from FoMoCo. Or is there another sensor? No ABS light... since no ABS. :shrug:

jngreen · Dec 24, 2012

Are you sure you don't at least have rear abs? If you don't have abs, I don't know what might be causing it.

HOOV3R · Dec 24, 2012

Trucks with rear ABS still only have the sensor on the diff. So it has no speed sensors in the front wheel bearings? If not, you might have a wiring issue.

Zmann · Dec 24, 2012

I don't think you can have rear only ABS so that would just be the VSS sender in the diff

I say this because with out the front senders how would the computer know
the rear tires were not at the same speed as the fronts and manipulate the braking ?

OP does your steering wheel loose power at the same time the pedal goes hard?

Zaairman · Dec 24, 2012

Rear ABS was standard back in 2000... ABS was an option. I can take you for a ride and jam on the brakes if you'd like to prove it...

ABS also gets you a discount on your insurance...which I don't get.

This issue happens on dry pavement. I haven't noticed the steering going out, but I haven't noticed since I'm usually focusing on, oh, my brakes not working. LOL I'll see what it does next time I have it out.

jngreen · Dec 24, 2012

My obs, which had rear abs only, had an abs valve on the frame rail that leaked and caused problems. I'm not sure if a 2000 would have to same type valve on the frame rail or not. If it does have the same thing, I replaced mine for cheap.

Zmann · Dec 25, 2012

Zaairman said:
Rear ABS was standard back in 2000... ABS was an option. I can take you for a ride and jam on the brakes if you'd like to prove it... ABS also gets you a discount on your insurance...which I don't get.

This issue happens on dry pavement. I haven't noticed the steering going out, but I haven't noticed since I'm usually focusing on, oh, my brakes not working. LOL I'll see what it does next time I have it out.

Interesting Thanks guys

Twan · Dec 25, 2012

My truck is doing the same thing, I was thinking it was my power steering pump.
Let me know what you find.

Zaairman · Dec 26, 2012

Twan, do 6.0s use the same Hydroboost set-up that the 7.3s do?

jngreen · Dec 26, 2012

Zmann said:
Interesting Thanks guys

They call it rear ABS, but it isn't truly ABS, if that makes any sense. So you are correct, the front wheels don't know what the rear are doing, or the other way around. I think its pretty much just a valve that pulsates the rear brakes in the event of a lockup.

Twan · Dec 26, 2012

Not sure 100% sure, but I think so.
My friends 2000, had a power steering pump going bad, but it felt like abs all the time.

Zaairman · Dec 27, 2012

Are the Cardone PS pumps any good?

Zaairman · Jun 9, 2013

Bumping this one back up, truck is still doing it and seems to be doing it more frequently now. Again, only right after start-up. I can hear something humming as if ABS is kicking in. Truck also pulls to the right when this happens. I mean the steering wheel will turn 90* if you don't hold on to it.

ointlaugh:

But, I think my truck was built on a Friday or Monday or something, cause it just doesn't make sense. It does not have ABS (confirmed via Ford and insurance letter). I can lock up the front tires. Snowy roads? No foot massage when you stab the brakes. Hell, it doesn't even have the ABS light in the dash (there is no bulb holder dealio in the cluster behind it). BUT, the truck has the wiring going to the front hubs for the ABS. And, it also has the #14 60a fuse (ABS module) under the hood.

However, after reading my owners manual, even if it is RABS only, it still should have the ABS light. Something screwy is going on.

ointlaugh: