1997 Dodge Caravan brake booster replace

Impossible or not you need to remove the stop light switch, the master cylinder, some boosters come with a new master paired to it, if this is your situation remove the steel lines, and electrical plugs, then get under the dash and remove the 4 main bolts, slip the eye of the booster rod off the brake arm and pull the booster out. Now what are your symtoms? A hard pedal? Could be the booster, or the check valve, remove the old valve from the booster, try blowing thru it both ways, you should only be able to one way.