1966 Brake Light Switch-Help!

I have recently replaced the master cyclinder on my 66.  However when trying to reconnect the brake light switch, I cannot get the brake lights to light up when pushing on the pedal.  The only way I can get a brake light(drivers side) to come on is by pushing the brake light switch either up or down instead of it being level like it should be.  I have replaced the switch and it still does not work.  They worked before I disconneted everything to replace the master cyclinder. The wiring is fine and the bulbs are not burned out.  What am I doing wrong?  Thanks!  

you might have broken a wire going to the switch.
my question is why did you disconnect the brake light switch to begin with when all you were doing is replacing the master cylinder.  

All wires look good.  You have to disconnect the switch in order to get the master cyclinder off.  The push rod runs through the switch.  At the time of removal, I didn't realize you could take the switch off without disconnecting the plug with the wires.  Plus I didn't realize it would be so difficult to get the brake lights working again.  Any other ideas?  

Could you have bent one of the connector pins in the plug, or could the plug not be completely seated into the switch?  You didn't pull any wires and break a connection up the wire or disconnect a ground?  

The only way I can get a brake light(drivers side) to come on is by pushing the brake light switch either up or down instead of it being level like it should be.

This is exactly the same problem I had long ago. Had to push up or down to get it to work and then it would stop. I had to get another switch, sometimes you get a bad one. I hate the way these switches are designed, the rod having to have enough give on its pin to press on the switch enough to close it. Use a test light or voltmeter to test for 12v and sw operation. Check fuses.  

I had the same problem after installing a Trans Am Racing power booster set-up and M/C in my 1966 a few years back. Just as Cushman350 said, the problem was the need for the pushrod at the pedal to have enough movement to depress the switch before it starts pushing the M/C rod in. Apparantly the tolerance changed when I made the swap to the Trans Am Racing setup. I needed to make the switch close quicker. So, I cut some 1/4" by 1" strips from a piece of thin sheet metal to use as shims. I then put 1 or 2 of the shims over the push/contact spot on the switch and bent them around the sides of the switch to keep them in place. The switch then worked fine since I had closed the gap just enough to allow the switch to close before the pedal started pushing the rod into the M/C.

This "temporary fix" lasted for 2 years before I was under the dash for something else and then decided to just replace the switch. I went to my local Mustang vendor down the street and picked up 3 or 4 different switches (different years, manual versus A/T, etc.). They each had different travel distances and spring tensions. The first one I swapped in worked without the need to add the homemade shims back in.  

I had the same problem after converting my '66 single resvoir master cylinder to the safer '67 dual resevoir master cylinder. There wasn't enough movement in the pedal with the new parts to activate the stop light switch. I had to get an adjustable pedal to m/c rod and build a little play into the system for it to work right again. Been fine ever since.