rebuilt brakes, ABS howl and pull to the left when braking | Page 2 | Ford Explorer Forums - Serious Explorations

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rebuilt brakes, ABS howl and pull to the left when braking

Having air in the ABS pump would not cause this. The ABS only activates if there is a wheel speed imbalance detected. You could have nothing but air in the ABS module and that would not cause ABS to activate when it shouldn't. Since you don't have the ABS light on, in theory the system can see the abs sensor is there, so the question is when is it not providing a good signal.

At this point I would try braking from faster speeds on good/dry pavement, not trying to lockup the wheels at all. If ABS activates while still going over 15MPH, in other words it always comes on when braking, or at least at any speed, you could have a wiring issue or the connector, either at the sensor end or the abs module end.

If ABS does not activate until going slower, this suggests a weak signal. If we can assume that after trying two sensors, one of the two must be good, this leaves distance and reluctor ring contamination, or less likely, a corroded connector or frayed wire (least likely).

Distance, possibly badly worn bearings, or a rust buildup where the ABS sensor mounts so it is sitting too high. You could plug the hole and remove the rust if the sensor gap is too great. Contamination, I don't recall if you mentioned whether you have RWD or 4WD/AWD, that should be in your sig or profile so people can see this! Okay now I see you mentioned replacing the hubs.

With a hub internal reluctor ring, it could be contaminated with grease that has metal particles in it due to the hub bearing failing or that grease gets slung up on the ABS sensor, so you put a new one in and same contaminated grease gets flung on the new one too. I would not rule out the hub even though it is fairly new, rather would check it. How about using a paintbrush down in the sensor hole to try to get as much grease as possible out of the reluctor ring teeth and wipe off the end of the sensor?

If you have the means to get all drive wheels off the ground, you can measure for the AC low voltage signal coming from the ABS sensors as the wheels turn. If you can't spin them fast enough by hand then let the engine do it. A multimeter can do this but a scope would be better to show the waveform from them.
 

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Caught a rainy day, and took the Ex out to see if I could activate the ABS. Tried a dozen times. ABS seems to growl every time I hit the brakes so thinking I did activate it I went back and bled a bunch of fluid through my power bleeder. No luck. Vehicle is now at the shop where they can apparently activate the ABS with their scan tool to bleed it. We'll see.
 






So, per my experience, this plugs in under the hood, and gives access to engine codes, but will it activate the ABS?
 






You're stating "growl" but do you mean you only hear a noise or are you getting brake system modulation, that you should feel through the brake pedal, and that decreases your stopping power?

If ABS is activating, it is not due to air in the lines. You could have nothing but air in the lines and all this does is make it harder to get pressure to lock up a wheel, would have a spongy pedal feel.

The only way to get ABS to activate is if it doesn't sense a wheel rotation signal so it assumes the wheel is locking up. If your ABS module has malfunctioned in some way, perhaps that could cause a noise alone, but then bleeding is futile, have to replace the module.

If the shop's tool can activate the ABS module then it likely can see the wheel speed sensor data and through a test drive, find which speed sensor is dropping out.

As has also probably been mentioned already, the easy way to check whether ABS is activating when it shouldn't is just pull the ABS fuse to see if the condition goes away, but then, I don't know about your '95 but on my '98 I then needed a scan tool to reset the fault code, didn't go away on its own when I put the fuse back in... don't recall if I tried disconnecting the battery first, probably not as using the scan tool I already had out was easier. That's for OBD2 though, don't know on a '95.
 






Having air in the ABS pump would not cause this. The ABS only activates if there is a wheel speed imbalance detected. You could have nothing but air in the ABS module and that would not cause ABS to activate when it shouldn't. Since you don't have the ABS light on, in theory the system can see the abs sensor is there, so the question is when is it not providing a good signal.

At this point I would try braking from faster speeds on good/dry pavement, not trying to lockup the wheels at all. If ABS activates while still going over 15MPH, in other words it always comes on when braking, or at least at any speed, you could have a wiring issue or the connector, either at the sensor end or the abs module end.

If ABS does not activate until going slower, this suggests a weak signal. If we can assume that after trying two sensors, one of the two must be good, this leaves distance and reluctor ring contamination, or less likely, a corroded connector or frayed wire (least likely).

Distance, possibly badly worn bearings, or a rust buildup where the ABS sensor mounts so it is sitting too high. You could plug the hole and remove the rust if the sensor gap is too great. Contamination, I don't recall if you mentioned whether you have RWD or 4WD/AWD, that should be in your sig or profile so people can see this! Okay now I see you mentioned replacing the hubs.

With a hub internal reluctor ring, it could be contaminated with grease that has metal particles in it due to the hub bearing failing or that grease gets slung up on the ABS sensor, so you put a new one in and same contaminated grease gets flung on the new one too. I would not rule out the hub even though it is fairly new, rather would check it. How about using a paintbrush down in the sensor hole to try to get as much grease as possible out of the reluctor ring teeth and wipe off the end of the sensor?

If you have the means to get all drive wheels off the ground, you can measure for the AC low voltage signal coming from the ABS sensors as the wheels turn. If you can't spin them fast enough by hand then let the engine do it. A multimeter can do this but a scope would be better to show the waveform from them.
Thanks for this input. yes, 4WD. Not to discount what you are saying, but I have gone back over what led up to this issue, and it all points to removing a brake line and opening the ABS pump to the outside. I had previously replaced both front hubs, but then during the build I replaced rotors and calipers, as well as the flex lines to the calipers. A tech had previously replaced the flex lines with some they said were longer, but weren't. I had some custom made for length, and when I went to replace them I realized the previous guys had cross threaded the passenger side at the hard line. Had to replace that to get it all back together. Oddly, when I got the vehicle back from the guys who did the lift and replaced the flex lines the first time, the ABS light was on, but the brakes worked fine. No pulling, or growling from the ABS pump, nothing but straight solid pedal, braking. This is not to say I cannot be experiencing some coincidental failure or issue. Everything under the front end of this Ex is new or nearly new or rebuilt because I just re-geared it, and replace everything except the hubs and one CV axle(the passenger side). The knuckles are new but proven to hold the abs sensor in the correct position because the ABS worked after they were installed with the lift.
 






You're stating "growl" but do you mean you only hear a noise or are you getting brake system modulation, that you should feel through the brake pedal, and that decreases your stopping power?

If ABS is activating, it is not due to air in the lines. You could have nothing but air in the lines and all this does is make it harder to get pressure to lock up a wheel, would have a spongy pedal feel.

The only way to get ABS to activate is if it doesn't sense a wheel rotation signal so it assumes the wheel is locking up. If your ABS module has malfunctioned in some way, perhaps that could cause a noise alone, but then bleeding is futile, have to replace the module.

If the shop's tool can activate the ABS module then it likely can see the wheel speed sensor data and through a test drive, find which speed sensor is dropping out.

As has also probably been mentioned already, the easy way to check whether ABS is activating when it shouldn't is just pull the ABS fuse to see if the condition goes away, but then, I don't know about your '95 but on my '98 I then needed a scan tool to reset the fault code, didn't go away on its own when I put the fuse back in... don't recall if I tried disconnecting the battery first, probably not as using the scan tool I already had out was easier. That's for OBD2 though, don't know on a '95.
You hear and feel the ABS growling. Pulsing in your foot. Braking power is diminished, and pulls to the left. Condition goes away entirely when the fuses for ABS are pulled. Brakes work perfectly. Perhaps the ABS system has failed. I am assuming the control module is part of the pump, and not separate.
 






You hear and feel the ABS growling. Pulsing in your foot. Braking power is diminished, and pulls to the left. Condition goes away entirely when the fuses for ABS are pulled. Brakes work perfectly. Perhaps the ABS system has failed. I am assuming the control module is part of the pump, and not separate.
I suppose anything is possible with 180K on the clock, but replacing brake hardware doesn't seem like a root cause for this kind of failure. Perhaps coincidental.
 






The control module is not sold separately AFAIK, but I do know that on some Fords it can be replaced seperately, reusing the existing pump assembly.

It seems far less likely to be the fault than the sensor, hub, wiring to it. You can spin the wheel and measure for a low AC voltage at the module connector, examine the wire for abrasion, could be shorting out or frayed. You could even run a new wire from the abs module connector to the ABS sensor connector or put a new connector on. New connectors are about $6 on Rock Auto.
 






The control module is not sold separately AFAIK, but I do know that on some Fords it can be replaced seperately, reusing the existing pump assembly.

It seems far less likely to be the fault than the sensor, hub, wiring to it. You can spin the wheel and measure for a low AC voltage at the module connector, examine the wire for abrasion, could be shorting out or frayed. You could even run a new wire from the abs module connector to the ABS sensor connector or put a new connector on. New connectors are about $6 on Rock Auto.
Tech read the codes, and showed faults for both front sensors. Also had a module fault. Trying to find a module now.
 






Anyone ever heard of Blue Streak Electronics? They sell remanufactured ABS modules at a reasonable price with core.
 






^ Never bought anything from them, appears to be a division of Standard Motor Products.
 






Blue Streak is a good old brand from before the 80's, I've bought their ignition products before.
 






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