When I hit the brakes on my 1997 Impreza outback Sport, it feels like the ABS brakes are coming on and it pulls hard to the right. It feels like the car wont stop, so I have to let off the pedal, then press it again, and sometimes it will stop doing it. It's doing this on clean dry roads, whether I'm going fast or slow. Sometimes it does it and sometimes it doesnt. Could it be a sensor on one of the wheels, or could the ABS module be going bad? I disconnected the ABS module and the brakes are working normally.

One of the wheel sensors may be going bad, or could have metal shavings stuck on the end, or the tone ring for that sensor is damaged or corroded so the sensor is sending a false signal.

 

If it pulls to the right I would suspect a problem with a sensor on the left side.

I have a sensor issue on mine but can't fix at the moment and have been putting it off. Normally, the ABS light will be on. A couple times when raining, the light has gone out. The last time the light went out, the car was doing the exact same thing as yours. If doing 40 mph, hitting brakes for about 5 seconds, all was normal. Once at nearly a stop, it did the same thing. Pedal went crazy, ABS pump was making a racket, braking effect worsened as the pedal pulsated, let off brake and pressed again and it stop for a second or 2. Kinda surprised it wasn't throwing a code for it and light was staying out.

 

Anyhow, after car sat and dried, it cleared the issue after a later restart and ABS light came back on, and brakes at least worked w/o the ABS pump going crazy. I believe you can pull the ABS fuse and at least get normal braking, but avoid hard stops as the wheels will likely lock up and cause skidding. But that's at least safer than the pedal pulsating and causing the car to NOT stop safely, and you'll be able to diagnose if sensors are dirtied up or have failed.

does the ABS light ever come on?  if so - read the codes.  it's really easy - ground one pin found under the dash - just above the gas pedal.  plug in pin to the right connector and the ABS light will flash the code ont he dash.  search for directions online if you ever get an ABS light on the intsrument cluster.

 

certain years around mid-1990's have an issue with the ABS hydraulic unit relay i think it is.  they usually buzz while the car is off and drain the battery. i'm not sure this applies to 97 impreza's but  i wonder if they can also freak out while driving?

Thanks for the info. I'll have to reconnect the power to the unit and see if I can get a code.