Overcharging alternator

[TomsSVX]

My 92 teal is having some weird issues. I get the christmas tree lights like the alternator was going bad, so I checked my voltage at the battery and at the alternator. I am showing 17.9v in both places... Here is where it gets interesting. When I hit the brakes, the lights go off like nothing ever happened but once I hit the gas again and get the rpms up, the lgihts on the dahs come right back up. Well, it doesn't look like I am losing charge, but it is over charging the system.. I figured the voltage regulator is shot and I ordered a new alt from a local pep boys... Anyone else have some insight??

Tom