The two main reasons for this is a sticky, or malfunctioning brake caliper on disc brakes, or piston on rear drum brakes. on the front disc brakes you can tell if your caliper is not releasing by driving slowly on a straight and level road, then let go of steering wheel and apply brakes (only go about 15 MPH). if it pulls suddenly to one side, chances are that caliper is sticking closed and upon inspection of that wheel , you will notice a less thickness of brake padding than the other side. Another reason is that the pads are down to the metal, and when you apply brakes, you have metal (from the worn pads) on metal (from the rotors). you should have been hearing a loud squealing noise prior to this. now you must change pads, and rotors. Or in rear, shoes and drum. Rotors or drums are most likely to have deep groves in them, sometimes you can just get them machined cut, less expensive.
warped brake discs can cause your brakes to grab in reverse. Hope this helps.
Centric brakes are brakes which grab the tire in the middle for slowing the vehicle down. Most brakes grab at the side which can lead to swerve on very rare occasions.
Sticking caliber. Flush the brake system and install fresh brake fluid, then bleed the brakes. If that does not help, replace both calibers and brake pads on the axle where the brakes are grabbing.
worn brakes could be the cause or check the A frame bushings
If you grab it like a spoon a lot then it could die
If the brakes on a Mazda 6 are squeaking, it could be indicative of a problem. The brake pads could be incorrectly set.
in VW's when you have the breaks adjusted out too far they tend to grab when reversing. There is an auto adjuster in the rear drum to keep your rear brakes adjusting. If the brakes are worn out they will "hang up" after reverse and cause squeeling.
it is friction and when the water goes on the brakes and tires they bond together
probably the return spring(s) are broken or the brakes are contaminated (gear lube from leaking axle seal) or if it hasent been used in a while they could be rusty.
rubbing from brakes or rubbing from frame