Vibration in Brake Pedal on 2004 Model

I'm thinking of buying a 2004 Suburban. I test drove 3 last night from a local dealer. I felt a distinct vibration in all 3 when sitting in Drive with my foot on the brake. Does anyone know if this is usual for the Suburbans. I'm heading out to a different dealer later today. Thanks in advance for any assistance.

Are you saying while stopped and in drive with foot on brake or while driving and applying the brake?
Either way I do not have this vibration in my 2004 Suburban.
Check the Leak Thread on thuis forum and if you buy one let me know what happens to yours.

I have an 04 Burb and I too have the vibration. It is quite annoying. I have discovered that it is present only when running the A/C. I have about 100 miles on it and I am hoping that it will just go away : ) If not, I will take it in, but have little hope that it will be resolved with the number of complaints I have heard about it.

Please eloborate on this vibration, what exactly are you doing when you notice the vibration?

Any of you notice the leak in the rear differential?

The details on the vibe are this:
1. AC is on
2. Sitting stopped with foot on brake pedal
3. Funny feeling in foot

Additionally - I have heard my AC make some really strange sounds inside. Almost like a grinding and leaking air compressor... ?

I have not looked at the diff, but I intend to.