ABS/brakes and more

[kcarner]

Have a 1999 Chevy Malibu. The brakes are acting up. When coming to a complete stop they will catch, let up and re-catch again. The car feels like it's lurching ahead when it does this. Strangely enough, the ABS light comes on periodically and when it is on the brakes work just fine.
My oil pressure light comes on occasionally only when making a left hand turn....usually a sharper turn. Oil is changed regularly and it is not low.

[Johnny R]

When did you buy this car? Did you buy it used? If yes, do you know its history?

[kcarner]

Yes, I did buy the car used about one year ago from Waugh's Auto in Maquoketa, IA. Unfortunately, I do not have a history report. Waugh's Auto is now closed because he retired his business (got a better close out deal) but his reputation in town was very good.

[Airjer_]

Do you hear the humming of the ABS pump and does the pedal feel different?

If so I think you are experiencing over active ABS. This is a fairly common problem for GM. What happens is for various reasons the signal from one of the ABS sensors will drop out at lower speeds. The ABS interprets this as the wheel being locked up (which it is not) and activates the ABS. If it happens pretty frequently than it will be no problem for a good repair facility to scan for codes and then monitor all four spped sensors on there scan tool. At slower speed stops they will be able to see the signal drop out and confirm the source of the failure (typically a bad speed sensor in your case).

[kcarner]

Thanks. I had it scanned a few weeks ago when the ABS light was going on and off and it didn't read anything. That is before the brakes started acting up like they are so scanning again would probably make sense. I don't hear any humming, just clunking but can feel it in the brake pedal and feels like it's coming from the underbody of the car.

[Airjer_]

So its a steady pulsation that makes the whole car shake when you apply the brake pedal? Its more noticeable at higher speeds and the frequency of the vibration changes with speed as well?

If this is what you are feeling than the rotors are possible warped. When I say possible there are other things that can cause this but the rotors are the likely cause.

The clunking could be a number of things but I think it would be worth you time to have the brakes inspected as well as the front end one more time. The good news is there are a number of shops that do these for little to nothing.

[kcarner]

Thanks for all your recommendations and time and effort....I am positive it's not the rotors.....had plenty of experience with those and other brake shoes/brake pads problems. This is a situation that I have never seen happen with ANY vehicle before. It really is difficult to describe. Had a passenger think it was my transmission once because of the noise. He was quite surprise when I told him it only did it coming to a full stop and would stop when the ABS light came on. Sure enough I was right. There is no actual vibration, just the clunking. When I said I could feel it in the brake pedal I meant the the way it seems to catch, release, and re-catch; not any vibration.
I do plan to get it checked out....had it scanned again today and wouldn't show an error code again! Then the other problem is when the light is on, the brakes don't act up so it's hard for a mechanic to feel what it does.
Will keep working at it though....again thanks!