94 Explorer - anti lock brakes pulsing when parking

Hello all -

For the past few months, my anti-lock brakes will activate when pulling into a parking space. It can be a shock sometimes when you feel like your brakes aren't working. Brakes are fine at all other times - only happens when the front wheels are cranked sharply.

Could this be some kind of sensor issue?

Thanks,

Randy

Reply to
Randy Johnson
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There is a sensor at each wheel which makes a pulse each time the teeth mounted to the hub line up with it. The ABS computer compares the time between pulses at each wheel to see if one is skidding and shifts the braking power to the other wheels. If you can tell which wheel is NOT braking, that's the one to look at first. A couple of possibilities come to mind-

  • the wire going to one of the sensors may be bad, so that when you stretch it by turning sharply the ABS computer thinks that wheel is not turning and activates the ABS.
  • your front wheel bearings may be bad, making them loose so they don't keep the teeth properly lined up with the sensor.

You should get this fixed ASAP or disable the ABS. It could cause real problems if it malfunctions at a critical time.

-Paul

Reply to
carbide

Just wanted to offer my experience here as well

I had a similar problem (that I initially attributed to ABS -which was 'incorrect' in a sense) that only existed when I was braking while executing a left turn at very low speeds. [EG: coming to a stop while turning left into a parking space.]

The previous owner obviously was financially limited, or VERY negligent...At any rate, I had already replaced the brakes. Also replaced the wheel bearings, and the brake line on the left front that was cracked (thinking that maybe the was a "pressure bulge" in the line that would exist only when the brakes were applied, but not enough to burst the actual line. < as suggested by a mechanic.)

I had done the calipers since the left side in particular was TOTALLY crispy. (-the piston had turned pink and white from such extreme heat, and actually cracked in half.) This should have been a clue in itself... but I overlooked this in the diagmosing process since I had SO much going with this truck at that point. Oi. Hindsight's 20/20.

At any rate, the truck would stop fine when driving forward (straight) and also be fine while braking and making a right...but try and make a left turn into a parking spot, or coming to any stop while the wheels were turned to the left = pulsing. But only once in awhile...(which got more frequent eventually, allowing more accurate troubleshooting, finally.)

All of the above was done at the same time (brake pads, calipers, bearings, brake line), but the 'pusling' still existed. I started to head into the ABS system but then thought further about it...and realized that I completely overlooked the rotor. No I didn't have them turned, even though the piston was "cooked" on the left side, oddly enough, there was no scarring/wear evidenced on either the right or left sides. Obviously this was an error in judgement. *sigh*

All of my other vehicles, I've had always showed "obvious" wear, and it was easy to tell that they needed to be turned... so the *one time* I assume they didn't need to be turned, bit me in the ass. -go figure. LOL

The fix (for me)?? Replace the rotor on the left (driver's side). Seems the extreme heat from the bad caliper had warped it (duh). lol

Moral of the story for me? If you're replacing brakes, ALWAYS have the rotors turned -> no matter HOW GOOD they look. At least it would have saved me a week's worth of "hunting" for the answer that had already slapped me in the face as plain as day.

GL with yours, and let us know how it turns out :)

Reply to
yarrrrrgh

Just wanted to also mention that, my original reply might only apply IF it's one side "pulsing" (since I posted to that effect) and didn't gleen from your post if it's only one side, or both...

At any rate though, hope you get it sorted quickly, as it is definately an unsettling feeling (as well as HIGHLY unsafe) when they do that...as I can relate a bit too well. ;)

Reply to
yarrrrrgh

Thanks for the help -

In my case it is either direction. I have had warping problems in the past and do know the feeling when that happens.

When the anti-lock brakes kick in you can hear the "groning" noise from in front of the driver. It is not where the brakes go out, they just work a little bit slower than normal. It only happens when the wheels are turned sharply. I have not found any signs of damage or wear on the wiring yet. I do need to pull the rotors to see if anything is messing with the sensor fins on the rotor.

The calipers were replaced two years ago - still the original hoses.

Hopefully I will find the answer soon,

Randyj

Reply to
Randy Johnson

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