When you raise the rear with the air bags you are now telling the truck that it does not need the extra braking force to the rear for the added weight.
This is what I did on two, Toyota Tundra’s. On the rear of most Toyota's is a diagonal bar from a valve to the rear diff. The bar allows the rear brakes to get more brake bias (force) to adjust for the load you put on the back. You add weight the bar moves, so then a valve opens more. Since you pump up the air bags the truck levels off and the so the valve closes as with no load. The system would not know it needs more rear braking force to stop. That's right the front brakes do more of the work.
I made an extension bracket that will extend the height where the diagonal bar attaches to the rear diff. Just a piece of flat stock steel works. Not too thick so you can use the same bolts. How much you need depends on your load and spring condition.
To find the spacer length needed: without the load (camper) on the back measure the height difference from the bar at the valve (near the frame) and the center of the round pivot at the differential. That will be you’re no load height and the brakes will work fine. Now add the load (camper) and average running weight to it. Now measure again the two reference locations. If you have air bags already you can flatten the air bags and drive around the block to settle the spring’s then measure.
You will notice the bar became flatter some. Let’s say you had a drop of two (2) inches. When you pump up your air bags to level the truck, you will want to make a spacer that you can raise the bar two (2) inches at the differential. All we are doing is keeping the bar at the same angle as before raising the rear with the bags.
This bracket works well if you have the camper on and off a lot. I can’t speak for other truck manufactures how they handle theirs; I’m just a Toyota guy.
Too much braking force on the rear with out the load will cause the rears to lock up on an icy road
. The Dealer or a trusted mechanic should have pressure gauges that they can measure your brake bias and set it properly. I take no responsibility for improper brake adjustments. You should decide if you need to take action and make proper adjustments.
