'Grabby' brakes

Just say'in its worth a check.... cost zero

I went through three boosters with the same issue...I though the same as you guys booster, ....turned out...worn drums and undercut rotors out of spec, and shoes on the rear that were old and getting close. Push the brake and GRAB, instant lock-up. A measure is cheap..easy and why not. I could be wrong...but that's my opinion , never say never, especially if someone's been there.