ok havin brake trouble with my 96 f150 reg cab short box. started doing it this mornign no matter what speed im going with even the slightest amount of pressure on the brake pedal the back lock up. i know this an abs problem but were should i start.

 

This just started happening? You haven't done any work on the brake system at all?

Sounds like your ABS valve is clogged up. The quickest, easiest, and best way to fix it is to bypass the valve with a piece of brake line and bleed it out.

 

ok can you give me a step by step on this im a little lost

 

Ok, let me start over then. If you've never worked on brakes before then you really need to pick up a manual or find a buddy that really knows what he's doing.

The first thing you should do is take all four wheels off and do a thorough inspection of all the pads, shoes, calipers, wheel cylinders, and brake lines. If you see any fluid leaking anywhere you need to find the source of the leak and replace that part. When you check the wheel cylinders pry the little rubber bootie off and make sure there is no fluid behind it. If there is you have to replace it. Also check the rear brakes out for broken hardware. Replace anything that needs replacing and adjust the rear brakes. I've posted in here quite a few times what the proper procedure is for adjusting rear brakes.

Do you have any lights on the dash? Like the ABS light? Does the speedometer work OK? If not and you are still having the problem then you are probably going to have to replace the ABS module. Let me know when you get this far and I'll tell you how to replace it. It's a pretty common issue on these trucks, the ABS system is not very good and this valve gets clogged up with rust and other debris pretty easily, leading to problems with the rear shoes locking up or not disengaging.