ABS Issue

[TripleC321]

Seeking some guidance on an ABS issue on my 1988. 
 

I had one front sensor go bad due to age and cracking, triggering the ABS light. 
 

I replaced both front sensors with recovered ones done by Jim Finn. When replacing the drivers front, I accidentally broke the sensor mount, so replaced it. 
 

after replacing the sensors, the ABS light goes away, but now the ABS seems to trigger randomly. I’ll be slowing down at a stop light, and the ABS will trigger while I’m slowing down, which almost causes me to rear end the vehicle in front of me since it wouldn’t let me apply brake power. 
 

I’ve tested the sensors front sensors using the how to guide and they come back correct. 
 

I did notice that my ABS tone right on driver side has a Nick all the way around. It appears the replacement mount I got makes contact with the ABS tone ring, despite it being a mount that came off another Reatta. And they didn’t make contact before. 
 

is the Nick on the tone ring causing this? Is something else at play?

[DAVES89]

I think you have two things going on here. The ABS does not cause a loss of braking power however it will come on [and so should the red light] when you don't have enough brake pressure to allow the brakes to work as designed. The loss of braking power is usually due to a failing accumulator ball. 

The barrel of the sensor lead should not touch the ring. It comes close but shouldn't touch. 

[Ronnie]

I agree with Dave. The yellow ABS light being on shouldn't cause a loss of power brakes.

 

Is the red brake warning light come on when you lose power brakes?  If the red light comes on it automatically triggers the yellow light to come on even if the ABS system is in good working order.

 

 

[TripleC321]

I guess I should clarify that it isn’t a loss of braking power. The ABS activating prematurely forces feedback and resistance on the pedal that makes it hard to physically depress the pedal, as ABS is designed to do. 
 

the accumulator has been replaced, and if I unplug a wheel sensor, disabling ABS, normal brake functions work normally 100% of the time without issue. I do not have the red brake light appear at all. 

[TripleC321]

3 hours ago, DAVES89 said:

I think you have two things going on here. The ABS does not cause a loss of braking power however it will come on [and so should the red light] when you don't have enough brake pressure to allow the brakes to work as designed. The loss of braking power is usually due to a failing accumulator ball. 

The barrel of the sensor lead should not touch the ring. It comes close but shouldn't touch. 

The barrel of the sensor does not make contact with the ring. However, the replacement sensor mount (cause it’s an 88) does. And no amount of adjusting seems to make it not make contact. On each boat hole theirs a flat spot to accommodate the axle, that flat spot is making contact with the tone ring. 
 

it’s weird cause the old mount, which was the exact same part, did not make contact. 

[Ronnie]

Can you remove the sensor and slide a washer like spacer over the barrel to give more clearance between the sensor and the tone ring? Also if the tone ring teeth have nicks on it you can file them down. I had to do that when I replaced my axle. The axle had been bumped and it had several nicks on it. It hasn't given any problems.

[TripleC321]

27 minutes ago, Ronnie said:

Can you remove the sensor and slide a washer like spacer over the barrel to give more clearance between the sensor and the tone ring? Also if the tone ring teeth have nicks on it you can file them down. I had to do that when I replaced my axle. The axle had been bumped and it had several nicks on it. It hasn't given any problems.

I can certainly add a washer, but to clarify it’s the mount that makes contact with the axle. (Or used to before it carved a grove). The sensor does have space between it and the axle. The sensor itself is not making contact. Just the mount. 

[Ronnie]

I changed my front axle not long ago. I didn't look at the sensor too closely but I don't remember a wheel sensor mount. I thought it bolted directly to the knuckle. Anyway, if the mount is hitting can't you grind off the portion that is hitting? Photos would help us understand the problem.

[TripleC321]

57 minutes ago, Ronnie said:

I changed my front axle not long ago. I didn't look at the sensor too closely but I don't remember a wheel sensor mount. I thought it bolted directly to the knuckle. Anyway, if the mount is hitting can't you grind off the portion that is hitting? Photos would help us understand the problem.

Only the 1988 has the sensor mount. 1989-1991 bolts into the knuckle. 

[Ronnie]

I've got an '88. Didn't know there was a difference. I'll take a look the next time I have a front wheel off. Something else I can add to my " '88 only list" I guess.

[TripleC321]

I’ll get a picture of the area next time I have it off the ground. Should be a few days. Hard to get a view with it on the ground.