Braking issue

1qwik99

1qwik99

Registered User
Hello !

1995 SC AT totally stock car 71K miles.

At a slow speed, like 5-10 mph I get a quick pulsation when I apply the brakes. It is extremely intermittent. Only happens at slow speeds, sometimes. Brake rotors have 20K miles on them look serviceable. Pads maybe 1,000K on them 75% meat left on them. We have vacuum bled the brakes 3 times, no change. No wheel shaking. Replaced both front upper control arms. Car drives straight as an arrow. Recently aligned by Ford, new tires. Nothing jumps out. Someone suggested maybe the ABS module is activating when it shouldn't. Not sure how to test that system. No codes on scan tool. Thoughts ?
 
Thought I would add to the thread. I went ahead and pulled the R/F tire / wheel. Pulled the Wheel speed sensor. It was caked with dirt / grease as was the tone wheel. I cleaned both of them with some brake Cleaner and a wire brush carefully on the sensor. Re-installed and now the ABS light is on. Not sure if that is a normal thing and it will reset after driving a bit, or if I messed up the sensor? Any help would be appreciated.
 
If you cleaned the sensor with a wire brush & lights on now I suspect its done.

A sensor &/or tone ring wont cause a pulsation during braking though. Were you able to narrow the problem down to the R/F, thats why you pulled that one?
 
All the videos I watched on YT showed that a wheel sensor can cause a slow speed ABS activation if the sensor is not functioning properly. I just decided to start with the Right side. It was very difficult to get off and there was some rust. I ordered a new Ford sensor to replace it. Although now the ABS light is on, it wasn't before. So, must have damaged it when I cleaned it. I believe it was an original sensor 30+ years old so I guess I'll eat that one. I plan on installing new hubs to both L/R and new sensors.
 
Were you having this problem, before getting new tires, and an alighnment? You can test the sensors, using a DMM, set on A/C, and spin the wheels. Note the voltage output. Also, check the resistance.
 
This problem has been going on for several years. I don't drive the car that much but it is an intermittent issue and an annoyance. I'm going to replace the two sensors first, (just got 2 NOS FORD ones off eBay $25.00 each) then move to the (FORD) Hubs, then to the rotors and pads. All those parts are 30 years old and still pretty cheap. It takes as much effort to remove and test them as it does to get brand new ones and install them. Thanks for the information though on testing !
 
1qwik99 said:
This problem has been going on for several years. I don't drive the car that much but it is an intermittent issue and an annoyance. I'm going to replace the two sensors first, (just got 2 NOS FORD ones off eBay $25.00 each) then move to the (FORD) Hubs, then to the rotors and pads. All those parts are 30 years old and still pretty cheap. It takes as much effort to remove and test them as it does to get brand new ones and install them. Thanks for the information though on testing !
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The rotors have about 20K miles on them and the pads are only about a year old.
 
Ok, the saga continues. I decided to look for the ABS test connector and I found it. After shorting the two pins, I got the following codes 32,41,42. then I made the required Ohms test while the sensor was still mounted in the wheel and got a steady 1169 ohms at the connector pins. I left the sensor connected to the wheel, changed the DVOM to AC current, spun the hub and got a steady AC current reading that fluctuated up as I spun the hub. I didn't go any higher up the wiring at this point, but it seems that the sensor itself tested good? Even though the code 32 says the sensor is bad (open or short RF sensor, wire harness). I haven't gotten to the left side yet. Any ideas on how to proceed?
 

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1qwik99 said:
Ok, the saga continues. I decided to look for the ABS test connector and I found it. After shorting the two pins, I got the following codes 32,41,42. then I made the required Ohms test while the sensor was still mounted in the wheel and got a steady 1169 ohms at the connector pins. I left the sensor connected to the wheel, changed the DVOM to AC current, spun the hub and got a steady AC current reading that fluctuated up as I spun the hub. I didn't go any higher up the wiring at this point, but it seems that the sensor itself tested good? Even though the code 32 says the sensor is bad (open or short RF sensor, wire harness). I haven't gotten to the left side yet. Any ideas on how to proceed?
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Old codes created while testing? Try clearing & go for a drive, see if they come back.
 
Funny thing is, I never got a light until I pulled the RF sensor to clean it. The codes say that both sides are having issues, which makes sense since this whole thing started because the ABS was activating at slow speed when stopping in parking lots mainly, and it was intermittent. Now that the ABS light is on and the ABS system is non functional, no more ABS slow speed activation. I'd like to fix it, but the car stops just fine as is.
 
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