Weird, Slight, Almost Unnoticeable Slip/slide (??) When Braking And Getting To About 20mph

[GallopGreg]

As I slow down - let's say from 40MPH - to a complete stop, once I get to about 20MPH or 19MPH I feel a slight slip or slide while braking. This is almost unnoticeable. I know I will need new brake pads in the rear soon. Any ideas what this might be? The car is a 2005 GT and has 67k on it. Please help!!!

 

[SpartaPerformance]

Automatic?

 

[GallopGreg]

Yes. I didn't notice it happening today though...

 

[Bullitt347]

What condition are the tires in? Are they inflated properly?

 

[GallopGreg]

The tires are in fair/good condition. They are low profiles and I keep the back at 42psi with the front at 40psi. I only notice it happening when I have been driving fora little while.