1998 electric club car golf cart rear brakes locking up

My husband and I purchased a used 1998 electric club car golf cart and when you step on the brake the rear brakes grab real bad. It almost throws you through the windshield. The man we bought it from (very trustworthy friend) said he had just had the brakes replaced not long before we bought it. When this happens with the brakes, it kicks the brake pedal back up. Do we just need to adjust them or could there be something else going on. My husband and the mechanic we always use for our cars are at their wits end.