96 cavalier with bad brakes?

I have a 96 cavalier with a 2.2L. and I am having problems with the brakes! Every time I try to stop the rear brakes lock up and then the abs kicks in and the abs continues pumping till you stop. Note: It has drum brakes. I have already taken apart the rear brakes and checked them out all hardware is good, shoes are good, wheel cylinders are good, I.E. at least they are not leaking, I can't tell if they are frozen but I don't think so. I have also completely changed the brake fluid in it hoping this might help some how, but no luck.



Does anyone have any ideas of what this could be?

Thanks!!

Please serious answers only. Thanks.96 cavalier with bad brakes?1 ABS and regular brakeing system r 2 differnt things

2 after replaceing 2 wheel sensors at 125 each...I pulled the ABS fuse and put tape on the ABS lite,,,,i learned driving before ABS was invented and think its an added expense to save idiot drivers

3 ABS computer cost a lot 300 to 1200 dollars
96 cavalier with bad brakes?
Ok this is straight out of my brakes class' shop manual.



1. Failed master cylinder.



2. Restricted brake lines preventing fluid to flow to front brakes(check your brake lines).



3. Defective proportioning valve allowing excessive pressure to rear brakes.



4. ABS fault



But again the most likely is a faulty proportioning valve on Drum brakes.
96 cavalier with bad brakes?
I have to go with Whoa D's answer. I'm thinking bad proportioning valve (or possibly another fault) is causing the rear wheels to lock up. When this happens your EBCM (Electronic Brake Control Module) is going to start seeing two different wheel speed signals coming from the wheel speed sensors. The rear wheel speed sensors will show a very low speed due to wheel lockup, and the front wheel speed sensors will still show close to actual vehicle speed. This would indicate to the EBCM that there is a wheel slip condition and trigger the EBCM to initiate an ABS stop and engage the ABS system. Just my .02, anyway.