Low Speed ABS Activation?

[HGKx]

I know what you are thinking by the thread title... "It's your ABS sensor my guy..."

But hear me out.

I bought the truck with the ABS light on, then I changed both sensors up front. ABS light went away. Great!

Now, on rare occasions... at low speed... the brake pedal, once depressed, suddenly gives at the bottom and you hear a noise that sounds like (what I assume) is like the ABS activating. Then it goes away and pressure back in the brake pedal.

Any takes on what this may be? Master Cylinder replacement, brake booster replacement, brake bleed?

Thanks!

 

[k1500 97]

I know what you are thinking by the thread title... "It's your ABS sensor my guy..."

But hear me out.

I bought the truck with the ABS light on, then I changed both sensors up front. ABS light went away. Great!

Now, on rare occasions... at low speed... the brake pedal, once depressed, suddenly gives at the bottom and you hear a noise that sounds like (what I assume) is like the ABS activating. Then it goes away and pressure back in the brake pedal.

Any takes on what this may be? Master Cylinder replacement, brake booster replacement, brake bleed?

Thanks!

I have the same problem but I took my abs fuse out, no problems, but it just feels like your driving a truck from the 70s n 80s n if your rear brakes are adjusted closer they will lock up first.

 

[Sean Buick 76]

Yup I had the same issue and after almost crashing because if it I removed the ABS fuse and haven’t had an issue since.

 

[Schurkey]

Connect a scan tool, find out what the ABS wants you to know. Look for "codes", but also verify the wheel speed sensors, especially if you can get it to act-up.

Yeah, the "usual" cause of ABS activation at low speed is low voltage from one or more sensors, and that's usually caused by a too-large gap between the sensor and the tone wheel. Sometimes rust on the mounting surface pushes the sensor away from the tone wheel.

 

[k1500 97]

Yup I had the same issue and after almost crashing because if it I removed the ABS fuse and haven’t had an issue since.

Yup my brakes actually feel better, I took the bulb out the cluster cuz I was tired of looking at it

 

[991500Burb]

I know what you are thinking by the thread title... "It's your ABS sensor my guy..."

But hear me out.

I bought the truck with the ABS light on, then I changed both sensors up front. ABS light went away. Great!

Now, on rare occasions... at low speed... the brake pedal, once depressed, suddenly gives at the bottom and you hear a noise that sounds like (what I assume) is like the ABS activating. Then it goes away and pressure back in the brake pedal.

Any takes on what this may be? Master Cylinder replacement, brake booster replacement, brake bleed?

Thanks!

I had the same issue yesterday. Drove my Burb over 200 miles with no issues. I went to park it and the brake pedal went to the floor! I almost tagged the truck in front of me. Surprised the crap out of me!

 

[evilunclegrimace]

I had the same issue yesterday. Drove my Burb over 200 miles with no issues. I went to park it and the brake pedal went to the floor! I almost tagged the truck in front of me. Surprised the crap out of me!

Your brakes need adjusted. I have the same issue with my '98 suburban. Low speed ABS activation, worse when it is wet. The pedal drops when the ABS kicks in but it never goes to the floor and the truck stops just fine although with a little extra distance traveled. I also have no codes and all of the speeds indicated on the scanner are the same.

 

[KansasOBS]

I'd be sending those ABS units to the scrap yard.

 

[991500Burb]

Your brakes need adjusted. I have the same issue with my '98 suburban. Low speed ABS activation, worse when it is wet. The pedal drops when the ABS kicks in but it never goes to the floor and the truck stops just fine although with a little extra distance traveled. I also have no codes and all of the speeds indicated on the scanner are the same.

Brake adjustment, as in rear drums? I did have an ABS light come on a few days ago, but went off after I drove it about a block. I will have to check if it stored a code.

 

[HGKx]

Connect a scan tool, find out what the ABS wants you to know. Look for "codes", but also verify the wheel speed sensors, especially if you can get it to act-up.

Yeah, the "usual" cause of ABS activation at low speed is low voltage from one or more sensors, and that's usually caused by a too-large gap between the sensor and the tone wheel. Sometimes rust on the mounting surface pushes the sensor away from the tone wheel.

I plugged in my scan tool, but its one of those amazon ones. So I'll likely need a better tool to check more in depth codes.