Is it the brakes?

[tkswan]

i hope the explination below means worn brake pads:

When the steering wheel is turned all the way to the left and i apply the brakes(pulling into a parking space), the ABS system is activating.

Opinions?

[shorod]

Are you certain the ABS is activating? Could it be the power steering vibrating? Do you feel a pulsationin only the brake pedal, or in the steering wheel?

Worn brake pads would not cause the ABS to activate. Maybe an improperly positioned tone ring on the rotor, but I'd be more inclined to think it's the power steering pump you're feeling.

-Rod

[tkswan]

Im pretty certian its the ABS system. it happens only when you apply the brake pedal so im sure its the ABS. besides, I have felt what the ABS feels like before on this car. The pulsation is definately in the brake pedal.

The front wheels aren't turned to the left stop. I try to avoid doing that to the front end so the ps pump shouldnt be under any stress should it? If you think its possibly the pump, shouldn't I feel it more evenly in the front end. I did some tests during lunch -- drove around in a left circle in a parking lot. ...looking like a fool. When I [gently] apply the brake pedal the ABS starts ABSing. Its all happening at the front right wheel when the steering is turned all the way to the left.

Is the tone ring another term for the speed sensor?

[shorod]

Ahh, that kind of detail helps. Your first post said " When the steering wheel is turned all the way to the left" which I interpreted to be "at a stop."

The tone ring is the toothed ring on the hub (I believe it's on the rotor, but will have to take a look). The speed sensor is a hall effect sensor that picks up the teeth on the tone ring.

If you happen to have access to scan tool that can access the ABS system with a datastream mode, then monitor the wheel speed during one of these operations and see if it happens to read 0 mph when the pulsation in the brake pedal occurs.

There are clips to hold the ABS sensor wires to the brake hoses in the front. Maybe someone left the wires unclipped and they got stressed. When you turn the wheel almost fully in one direction, the wires bend in just such a way that you get a momentary open condition, causing the ABS to kick in. You are at such low speeds when turning this sharply that the ABS doesn't pick this up as a faulty wheel speed sensor.

-Rod

[tkswan]

well i dont have access to the scan tool you are mentioning. I [did] take the wheels off and inspected the brakes and suspenson assembly to look for any obvious damage or loose wiring. I found nothing. The brakes still have about 30% of pad left on them. The hub and speed senssor has a protective cover over them and i couldnt see how to dis assemble it to get access. but from a quick view they seem to look ok. The cover is clean and dry and has no dents or hard nicks on it.

This problem [may] be getting worse. Recently, i made a run to catch a stale green light. ...pushed it to about 50 then slowed quickly before i entered the intersection. Once in the intersection I needed to make a left (close to 90 degree) turn. I took the turn quick and in control. While slowing AND turning left the ABS activated again. I would say the front wheels were turned left about 45 percent. The car is braking fine but i should'nt feel the ABS in these situations. When this happens its sounding like brake pad rivets grinding against rotors. This is why my first thought was the brakes.

[tkswan]

Wow. No opinions on this issue either.

[shorod]

The sound of brake pad rivets grinding against rotors is not what I would consider the ABS similar to.

Since one of your other posts implies you have the V8, do you also have the AdvanceTrac rather than just traction control? If so, you should have an indicator in the instrument cluster that comes on if the ABS kicks in. Does that indicator come on when you suspect the ABS is active? Find a loose road and do some tests there to see what the indication, if any, is when you would expect the ABS to engage.

-Rod

[tkswan]

good point, I [do] have the traction control and the abs indicator in the instrument panel but i never noticed whether or not its flashing when this is happening. ill take a look next time it happens.

Thanks

[tkswan]

Rod,

I got a chance to check it out today. Thisgrinding like noise is coming from the right front wheel (i think) and is happening whenever the wheels are left and the brake is applied. Even when left turn pulling into a parking space. The ABS light is not coming on but I feel ABS like pulses in the brake pedal. I grabbed the wheel from the top and pushed it in and out to see if its loose or if the bearings may be shot. Nothing. it feels nice and firm.

[shorod]

How about pulling the ABS fuse and trying the same experiment. If with the ABS fuse pulled you still get the same sensation, then you'll want to focus on something mechanical such as wheel bearings or tires (rotate front to rear).

If the pulsation goes away with the ABS fuse pulled, then you need to focus on a wiring issue or tone ring crack/placement issue. That would probably be most easily detected with the use of a scan tool that can access the ABS computer and display individual wheel speed readings in datastream mode.

-Rod

[tkswan]

i spoke with the service rep at lincoln today, im trying to figure out exactly what scan tool i need to get, who has it, can i rent it or do i have to buy it, exactly what is the tool called. scan tool? i also explained the symptoms and the grinding sound. he said the sound i am hearing is what they call "abs pump growl". ...he said that sound was normal when the abs activates.

[shorod]

The tool I have is an OTC Genisys scan tool, it allows access into the ABS computer as well as many other computers on the car. I believe the Snap-On MT-2500 also has the capability if loaded with the appropriate software. The dealerships should also have the capabilty to access the ABS system, and their diagnostic fee will probably be less than the cost of these tools.

Actron also has a new consumer-grade ABS scan tool, but I'm not sure if it has the datastream capabilities.

-Rod

[tkswan]

Hey Rod,

I paid Lincolon $99 for diagnostic and the ghost wouldnt show itself. So I let it be for awhile and the ghost is back came back. THIS time the first indication was on the instrument panel. The computer toned me and the ABS light and the traction control lights are on. Wierd becasue once i park for awhile and come back to the car, the traction control light is off but the abs light stays on until I tap the brake pedal. This behavior has happened twice.

So I rotate my wheels last weekend and decided to pull the sensors and inspect and clean them. I stuck a wd40 soaked q-tip in the front sensor ports and spun the wheel to clean off that ring. Lots of black muck on the q-tip but they eventually cleaned off. I got it all put back together. Cleaned off alll the sensors and wala! the problem is gone. Not so fast, after about 5 days the ghost has returned. Is there a way to do a continuity test on each sensor to see exactly which one has the short in it?

[shorod]

The best method would be to use an oscilloscope to monitor the sensor as each wheel is rotated. That way you could compare levels as well as see if there is a missing tooth or gap between pulses (indicating a cracked tone ring).

Also, since the ABS light was recently on, there should be a stored code in the ABS system. Maybe the dealer would scan for free since you already paid them for a "diagnostic" and they didn't give you one. Reading codes in my mind does not consist of diagnosing anything.

-Rod

[tkswan]

ok. Once the abs light goes off will the code still be in the abs computer? Also, couldnt i rule out a cracked or broken tone ring since its not a constant problem? I fugure if something was cracked or broken the problem would always be happening. I drive a minimum of 50 miles daily during the work week. The problem didnt show up for about 250 miles.