99 Ford Ranger ABS issues...

Hello,

Front brakes were metal to metal. Replaced pads, rotors and cleaned up very nice. Upon test drive, truck acts like ABS wants to engage on slowdown or hard braking, but doesn't. I can feel the pedal pulsate and the ABS engage then disengage. There are no ABS lights on or brake lights on. I scanned with engine diagnostic because that's all I have and figured why not just look and see if anything pops up. I am sure this is ABS related. Anyone have any ideas or hints about how to isolate and identify this issue? I'm thinking maybe brake module or speed sensor etc etc, along those lines, but don't want to needlessly start replacing parts. Everything on front seems tight and good. But if the ABS light is not on then what could be making the ABS system want to engage in front when braking?

Thanks a bunch.

Are you sure there's a problem? I just had the front rotors on my 97 Taurus GL resurfaced and the pads replaced and it took me about seventy miles for the pads to seat themselves properly and another hundred miles or so for the brakes to really start snapping when I step on the pedal.

And yeah, it did and does feel different than what it used to and I've put about three hundred miles on the car since then.

Give the truck a few miles to seat the pads properly UNLESS THERE IS A PROBLEM WITH BRAKE PERFORMANCE after the brake job. If that's the case, don't drive it. Otherwise, see if it improves or a light comes on or something.

If you have no ABS light coming on and no apparent braking problems then it is quite likely your brakes are performing normally. In an emergency stop it is normal for the ABS system to be active and you will feel it to different degrees depending on the nature of your stop. If you don't feel any symptoms ie. pulling, skidding, etc. I would not seek neither diagnosis nor repair. You have just probably became more sensitive to this after you replaced the brake components. My thoughts are that the system is acting as it always did but you are just more likely to notice it now that you are testing it more thouroghly. Let us know if anything strange happens under normal braking conditions.

Mike

Thanks for your replies. Let me clarify a little here. Brake seating and normal ABS operation aside. The ABS is acting differently than it ever has before. It is engaging at low speed slow down. It indicates to me a problem with the ABS system, but no way of pulling codes w/o an ABS scanner. It could be a sensor or something along those lines, but I need to somehow pull the ABS codes, if any. So, anyone know how to pull ABS codes?

I've checked my service information and there is no way to read codes without a scan tool that can communicate with the ABS module. Some of the older Fords used flash codes but not in 99. Your sensor ring is part of the rotor and may have some damage to it or metal shavings adhered to the ring or the sensor. Even loose wheel bearing adjustment can cause a false reading at lower speeds and turning corners. Make sure the ring is not cracked, chipped or dirty. Blow the sensor and ring area off with air, check for wheel bearing play. If you need the codes you may have to find someone close to you with a scan tool. Not all low cost scan tools will do Ford ABS so be careful if you plan to purchase one yourself. Good luck . Keep us posted.

Thanks for the reply Mike.

I checked everything I could as far as dirty ABS plugs etc. The brake job is good. There is no play whatsoever in the front end to indicate a bad wheel bearing or other. Even slowing down normal/easy and that last little bit the pedal travels and then the ABS kicks on. No leaks in the brake system to sway me that way. I do wonder if the master cylinder going bad would cause the pedal to travel and initiate the ABS going on. Brakes are real good and there's no fade in the pedal, just seems like the ABS might be kicking on as a result of something else. As I said before though, no ABS light so I am assuming now that there must not be a code for ABS stored in the system. That would indicate to me a hardware problem somewhere. But what. A good question is....Why would the ABS engage under normal conditions? It seems like something is telling it to engage along the line. But, I will figure it out sooner or later. Just wish it was sooner...lol.

We had a little trouble on Suburbans when I was at a GM dealership that were doing the same thing. Tech assistance had me monitor both front wheel speed sonsors with an AC Voltmeter. A lab scope is nice but a voltmeter will probably work if the problem is sever enough. Each tooth on the ring generates an AC voltage pulse that the controler counts to calculate wheel speed. The faster the ring is spinning the higher the voltage generated. At a low speed a weak sensor can get too low for the controller to read and is interpreted as a wheel that is not turning. The controller kicks in limiting breaking to the opposite side wheel. Try comparing resistance from sensor to sensor. If no great difference then see if you can run a couple of wires securely back into the cab and compare each side AC voltage level at the slow RPM. See if one side is significantly lower than the other.