Sportruck.com - How to - Belltech 5/8 Drop

At this point a notch, called a C-notch, is usually cut in the rear frame rails to allow axle travel. Plates are then bolted to the frame rails to reinforce the frame where it was notched. The regular C-notch supplied with the Belltech flip kit provides an additional 2 to 3-inches of axle travel. With a 6-inch drop, this amount is adequate, but in order to get down to 8-inches or lower at the rear, a larger notch may be necessary. Even with a 6-inch drop and the C-section, airbags or helper springs are necessary to keep the axle from bottoming out on the frame when towing, especially if you have an extended-cab truck. We elected to go with a Super C-Section, which will allow 8-inches of rear drop to be used without the addition of airbags or helper springs at this time. The Super C-Section will even allow proper axle clearance to set the truck on the ground. Neither the Belltech C-notch nor the Super C-Section require the bed floor to be cut and the drop does not alter the payload capacity of the truck.

Here is a view of the trimmed bed support. Notice the brake support bracket has been removed from the frame rail, leaving two empty holes on the right side of the picture (the bracket is hanging just below the frame rail).

Because we will be welding our reinforcement to the frame, it is important we have a good, clean surface to work with. We have found the best way to do this is by using Brake and Parts Clean, which quickly dissolves the frame undercoating. After applying the cleaner, it only takes a few swipes of a sharp razor blade to completely remove the undercoating from the frame.

Carefully align the position of the notch and trace the outline of the section to be cut. Using a plasma cutter, remove the section of the frame rail.

It is vitally important that the frame is properly supported. Jack stands must be placed on both sides of the frame rail to prevent it from bending while material is being removed.

Here are three views of the Super C-Section we used on our project truck. Because so much of the frame rails will need to be trimmed, the notch will need to support much of the load on the rear frame. Notice the heavy-gauge square beam used, which will be welded to the top of the existing frame rail to supply much of the new strength.