92 sunbird rear wheels lock up
 

i have a 92 sunbird i have not driven on the road yet ins. starts thursday so i will have a better chance to check it out but with just going back and forth in my driveway the rear wheels seem to lock up easier than i think they should . the car has abs and it appears to be working fine with no error codes or lights. what could cuase the wheels to lock up, the shoes and drums are like new and no leaks anywhere. the self adjusters have been backed off to see if that made a difference but it did not.