signs of a bad abs unit?

[supreme_1]

does anyone know what the signs of a bad abs unit is besides the obvious visible defects.

reason being, i have a 98 q45 that slowly depresses the brakes as i drive ( the car feels like its braking on its own all the time) after i sit the car for about an hr it unlocks its self and drives normal till about 30 minutes of driving. it feels like both my rear wheels are locking up

[supreme_1]

anyone? could it possibly be anything else, maybe master or booster?

[devnull]

It could be the brake booster, or the adjustment on the pushrod between the pedal and the booster. If the brake booster was constantly engaged, it could possibly activate the brakes on it's own.

You could disconnect the ABS unit and then take it for a drive.

[projectRDM]

Disconnecting the ABS unit itself (the control unit) will put in safe mode, better choice is to unplug the ABS actuator directly. Drive it for a bit and see how it reacts.

[270R]

1. water/moisture + heat = expand .
2. moisture + brake fluid = contaminated .
3. driving = heat heheh
4. expand + brake fluid = unwanted braking

lol check ur brake fluid first before buying something u dont need

[supreme_1]

alright i'll try unplug the actuator and drive it for a bit.

i was going to see if my friends scanner had a abs scanner in it. i was also planning on bleeding it when i jacked up the car to see which wheels actually locked up.

[Matej]

You can usually tell if the ABS is going bad when you start crashing into things while trying to brake.

[supreme_1]

why thank you for your helpful advice.

[projectRDM]

The CONSULT can scan the ABS system for problems and do a self test if you know a Nissan tech who'll be nice.

[supreme_1]

i do have a friend that works there so hopefully he has some free time to check it out.

till then, i am going to have to figure things out without the consult scanner.
i unplugged all 4 harnesses attached to the ABS unit and i felt a change in the vehicle. it isnt as sluggish when getting on the gas and my pedal isnt so sensitive when pressing it.

im guessing these are all signs leading to a bad ABS unit? would scanning it show that it is indeed faulty? Or would it only show me if a sensor is bad? could it possibly be just a sensor?

[S14DB]

Unplug the ABS computer not the Actuator and drive.

Could be just a sticky caliper.

[270R]

water expands brake fluid does not ...

[supreme_1]

i've been meaning to bleed the brakes but i havent had a buddy thats been free to help

[supreme_1]

im nearly certain its not the abs at this point. i've been driving it unplugged for about a week now and it still acts up. im going to be bleeding it tomm and checking for signs of uneven wear on my rotors/pads.