2001 GMC Sierra brake problem

[Isaias R Cedillo]

I have a weird issue with my brakes. Sometimes when I am coming to a stop my brake pedal get hard and makes a grinding noise. Almost like abs is kicking in. I've replaced everything except for the master and booster witch I don't think there the problem. If anyone has an issue like this before any info would be appreciated.

 

[mindless1]

If ABS is kicking in you should feel it in the pedal ?

Which corner is the grinding noise coming from?

Did you replace everything trying to solve this problem, or due to normal wear and the problem only surfaced after the replacement parts were installed?

What is "everything" you replaced? Did you take a wire brush and clean rust out of the pad slider rails and put some brake grease on them? Sometimes they can constrict pad movement even if the stainless guide in them looks good so it needs pulled off to clean that out then the guide put back or a new guide.

Did you lube the slider pins? With lube compatible with what was already there?

You may have to jack it up and examine it again. The longer this goes on the more one wheel's hardware should show a difference from the rest. Is it possible you have a hub bearing going out?

 

[Isaias R Cedillo]

If ABS is kicking in you should feel it in the pedal ?

Which corner is the grinding noise coming from?

Did you replace everything trying to solve this problem, or due to normal wear and the problem only surfaced after the replacement parts were installed?

What is "everything" you replaced? Did you take a wire brush and clean rust out of the pad slider rails and put some brake grease on them? Sometimes they can constrict pad movement even if the stainless guide in them looks good so it needs pulled off to clean that out then the guide put back or a new guide.

Did you lube the slider pins? With lube compatible with what was already there?

You may have to jack it up and examine it again. The longer this goes on the more one wheel's hardware should show a difference from the rest. Is it possible you have a hub bearing going out?

So I replaced everything except the gear that sends the signal for the rear speed Sensor. I then pulled the fuse for abs out and problem is solved temporary. Gonna need to replace that gear but it is in transfer case so I just need to wait for funds.

 

[mindless1]

Okay, before everything was everything except master and booster and now everything is everything except the gear. It would be much better if you don't use the word everything anymore and instead list exactly what you have done. Some people's idea of "everything" is different than others.

For example did you replace the ABS module? That would be sort of an expensive random thing to do unless you were sure it was the problem, yet you necessarily did replace it if you replaced "everything". I'm not suggesting it's the problem, just that you completely ignored my post.

If it is the speed sensor then that should show up on an OBDII scan tool that shows live data.

 

[Isaias R Cedillo]

Okay, before everything was everything except master and booster and now everything is everything except the gear. It would be much better if you don't use the word everything anymore and instead list exactly what you have done. Some people's idea of "everything" is different than others.

For example did you replace the ABS module? That would be sort of an expensive random thing to do unless you were sure it was the problem, yet you necessarily did replace it if you replaced "everything". I'm not suggesting it's the problem, just that you completely ignored my post.

If it is the speed sensor then that should show up on an OBDII scan tool that shows live data.

Ok I'm sorry I said everything I replaced both front hubs, all 4 rotors and pads,front driver side caliper, and rear tire speed sensor(it did come up in scan)but the problem was still there. After I pulled the abs fuse the problem went away but is not fixed.

Okay, before everything was everything except master and booster and now everything is everything except the gear. It would be much better if you don't use the word everything anymore and instead list exactly what you have done. Some people's idea of "everything" is different than others.

For example did you replace the ABS module? That would be sort of an expensive random thing to do unless you were sure it was the problem, yet you necessarily did replace it if you replaced "everything". I'm not suggesting it's the problem, just that you completely ignored my post.

If it is the speed sensor then that should show up on an OBDII scan tool that shows live data.

Sorry I said everything I replaced both front hubs,all 4 rotors and pads,front driver side caliper, and rear tire speed sensor(it did come up in scan) the problem was still there until I pulled the abs fuse. Now the problem is gone but not fixed.

 

[NutBucket]

Did you inspect the front wheel speed sensors to make sure they're not messed up?

 

[Isaias R Cedillo]

They are a part of hub assembly so there new too. I think the problem is the rear magnetic gear. It's ether gunked up or damaged. Unless there is another abs part that I don't know about.

 

[mindless1]

You still haven't mentioned if the parts you replaced were to try to remedy this problem or if it only happened after you did brake work for *normal* maintenance reasons. I wrote the things I did for a reason, and cannot participate in a chaotic topic where there is not systematic elimination of cause.

Remember, only you know the history of the vehicle and the timeline for this problem.

Regardless, get another person involved and determine where the grinding noise is coming from.

 

[NutBucket]

Or worst case it's a busted/corroded connector/wire. That'll be tougher to diagnose.

https://www.scantool.net/scanxl-std/ has a plugin for GM ABS systems. Might be worth looking into to see what exactly is happening.