cant find cause of ABS problem
Asked by bighorn Sep 12, 2010 at 02:44 PM about the 1995 Lincoln Town Car Signature
Question type: Maintenance & Repair
ABS chatters when coming to a stop at slow speed, or reaching the end of a stop. It also activates when on a dirt road that is bumpy. It also activates while going forward on a bumpy road without stepping on the brake at slow speeds. The idiot light does not go on during all this. A mechanic hooked his computer to it and did not receive any problem messages. Any ideas.
10 Answers
That is very unusual. If I understand correctly, your car is braking by itself without you touching the pedal.? Take a look at the front and rear ABS 'sender' rotors, and make sure they are not caked up with metal debris and any oil or dirt. The sensors 'read' the metal fins and the spaces in between to compare the difference with each wheel and apply the brake pressure accordingly. If a rotor valley is packed with metal filings, the sensor may be tricked into thinking that wheel is locking up and actually remove brake pressure from that wheel, making braking distance even farther! Cleaning up these valleys and voids on the rotors will only help the system when the brake is applied by you. This will have NO effect on the vehicle braking on its own. Thats a totally different cat! Could be something to do with the speed sensor located in the transmission.
prior to this problem had to replace right front sensor five times in three years. Finally had a mechanic check the reflectors and found a small piece of a prior sensor that was magnetic. it would flop around and block the wheel sensor now and then. At that time had all the reflectors cleaned. This problem started about a year later. While the car does not actually brake the brake pedal does vibrate and the ABS pump does chatter while going forward at slow speeds. Just afraid the brakes might engage. Sounds like a short somewhere that is sending false info to the computer. Was hoping someone might have had a similar problem. Thx for the reply. B
THEGOLDENHORNET answered 13 years ago
MY 1997 TOWNCAR HAS THE SAME PROBLEM. WHEN I HAD BRAKES PUT ON ALL THE WAY AROUND ABOUT 2 YRS AGO, I HAD TO GO BACK AND PUT NEWSECONDARY BRAKES ON WHICH I WAS UNAWARE OF AND NEVER CHANGED SINCE I HAD THE CAR BRAND NEW. THATS WHEN THE ABS CHATTER STARTED AT SLOW SPEEDS. I READ SOMETHING IN A REPAIR MANUAL THAT SAID SOMETHING ABOUT AJUSTING THE PARK BRAKE CABLE WHEN REPLACING THEM BUT I BELIEVE IT HAS TO DO WITH THOSE SECONDARY REAR BRAKE SHOES. THEY APPARENTLY ENGAGE TO HELP SLOW THE CAR FROM HIGH SPEEDS. I BELIEVE THEY HAVE TO HAVE THE RIGHT PRESSURE WHEN THEY KICK IN AND I THINKTHEY ARE DOING IT AT LOW SPEEDS, THUS CAUSING THE ABS TO CHATTER. OVERALL MAYBE THE ABS NEEDS TO BE RECALIBRATED OR SOMETHING. I'LL FIND OUT AND POST AGAIN.
i think the problem with the abs false cycling has to do with the frt abs sensors. they read in hertz which is a very fine signal which will cause a false cycle but will not kick the abs light on. the fix is replacing the frt sensors & replacing the harness side connector terminals.
I'm having this exact problem. Where are the ABS sensors located in a 1998 lincoln continental?
THEGOLDENHORNET answered 9 years ago
Turns out that the sensor is pointed a ring of grooves on the rotor it calibrated speed based on how fast the grooves past In my cases the repair shop replaced a rear axel which had the wrong grooves on the rotor thus giving a faulty reading
Squirrelyman answered 8 years ago
Same issue, had old parking brake pads that were bonded that broke apart in layers. That put a sizable dent in the ABS ring on rear axel and damaged the sensor as well. Pulled 50 Amp fuse for it rebent the ring to how it should be and getting a replacement abs sensor before winter starts.
WhatsUpDoc answered 5 years ago
1998 Lincoln Town Car Signature Series having same exact issue. Whenever I get to 5 mph my ABS Pump activates whenever my brake pedal is being pushed in to slow down. Its always at 5mph. So I have changed the front brake pads and ALL 4 sensors to no avail. Tomorrow I am going to change the rear secondary disc brakes. BTW the rear disc brakes don't need adjustment of the parking brake if they are disc brakes, only the old drum brakes do you adjust them. I know from experience. If this does not work, I already have a used ABS pump ready to go in, as the previous own already changed out the ABS Module. This Lincoln only has 85,000 miles on it and its in excellent condition, one of those grand dad garage kept vehicles....Will reply tomorrow..
it sounds more like a a electric brake pump i just replaced my fathers rear axle bearings and seals along with the transmission and bushing on the front lower controle arms his abs and trac lights are on after driving for a day i do not think its the abs pump the light would come on if it thought 1 of the wheels were locked up on the other towncars but his a 07 excecutive l factory stretch bout 8 to 10 inches longer then normal
Folks you need to check the tone ring that the abs sensor reads there should not be any chipping missing teeth also if there is any buildup of metal shavings from worn out brakes this should be cleaned up the computer count can be effected by this and give an inaccurate reading causing premature abs actuations