They guy my truck has started making a rattling sound when I apply the brakes n go over any kind of bump in the road, it does not make this sound when off the brakes. Wat could be causing this

 

where's the rattle coming from? Front or Rear?

 

Sounds like its from the front but alignment shop says everything is good

 

Shakes and rattles can telegraph and sound like they are coming for one area, when if fact it could be the opposite end of the truck.

Assuming it's not brake related, then I would get the truck up on jack stands and get underneath it looking for anything that needs to be tightened up.

When I was in the autobody trade a squeek and rattle man was worth his weight in gold.

 

Can you describe the "rattle" a little better? Does it sound like a marble in a tin can, or kind of like two light pieces of metal contacting each other? Perhaps you are metal on metal at one or more of your brakes? This happens a fair deal in Jeeps, especially when they get dirty a lot. When's the last time you checked your pads? Just because they aren't squealing doesn't mean they might not be in need of replacement.

 

Front r new I'll have to check the back