My rear brakes locked up on my 1997 chevy suburban on 1997 GMC Suburban 1500

What would make the rear brakes lock up on my 1997 chevy suburban?

Asked by for the 1997 GMC Suburban 1500
2 answers
Assuming you have rear drum brakes, you could have wheel cylinder issues, adjuster issues, hardware issues, axle seal oil leaks... A good inspection - soon - is in order.
does it have hub brakes on rear wheel cylinder probley leaking shoes are soaked with fliud replace wheel cylinder and shoes clean every thang with brake cleaner