ABS or Hydro Boost problem?

[Guitar Jones]

Maybe some one here that has experience with the GM trucks may have come across this before. I have a 2002 GMC 2500HD 4wd. When lightly braking just before the vehicle comes to a stop it feels like the ABS is working, doesn't do it all the time but it's worse when it's cold.

I'm not sure if it's actually the ABS or the Hydra Boost though. I don't want to waste a bunch of money guessing as to what this is because I'm sure neither the ABS unit or the Hydra Boost unit are cheap. Truck stops fine though, with no other issues.

Any help would be greatly appreciated.

 

[NioMarvin83]

This is a common issue on older GM trucks like yours. It is likely the ABS. When the truck is almost stopped, the ABS may turn on by mistake. This often happens because of rust or dirt at the front wheel speed sensors, especially if the truck is used in wet or salty areas.

The sensor gives a bad reading, and the ABS thinks the wheel is locking up, so it turns on.

You can try this:

Take off the front wheels.

Find the wheel speed sensors on the hubs.

Clean where the sensor mounts. Rust can lift the sensor and cause bad readings.

Make sure the sensor is not damaged.

If cleaning does not help, the sensor or hub may need to be replaced.

It’s probably not the Hydra Boost if the brakes feel strong and there’s no hard pedal or noise. Start with the sensors. It’s cheap to try and fixes the problem for many people.