Look for wetness (brakefluid) between the master cylinder and the vacuum booster. If wet, replace master cylinder. If not, rear drum brakes out of adjustment or leaking cylinders. Also, if it seems to grab when stopping, you might have the rears looked at. Drums could be out of round as well. or a bad hose ballooning could do this and be ready to burst. Make sure to look inside dust cover on wheel cylinders, for, they may look dry but be trapping fluid under covers. If leaking, or low shoe lining, replace hydrolics, shoes, Hardware, resurface drums or replace, adjust properly and bleed system properly. If 4 wheel disc, I would suggest having a shop look at the brakes. Also, there could be air trapped in the system,
Hope some of this helps.

Answered by aacplus
2 questions asked