Truck bounces in rear when brakes applied

Hello, unfortunately it's hard to understand what you are meaning. If you're saying that the rear bounces over bumps more when the brakes are applied -- it may be a normal characteristic of the light rear end in an unloaded pick up, a choppy road, brake application and a more firm suspension. I don't know if you have any modifications, don't know the roads your driving on when it happens, the intensity of the application of brakes. I don't know what kind of load you may be carrying. As a result, I'd highly suggest a shop near you have a look. You could even have a false anti-lock brake system application -- it's so hard to know by a few words! www.repairpal.com/repair-shops