02 Durango Brake issues

My friends Durango is having strange brake problems. much like in this thread http://www.automotiveforums.com/vbulletin/showthread.php?t=944951

The difference is that if we rev the engine the brakes work fine.

Front pads and rear drums changed recently. rear drums work fine.

When front pads were changed, we did bleed the brakes.

Any help or questions for diagnosis would be greatly appreciated.

Thanks,

KX