Thread: need some backhalfing help

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ok im considering a backhalf on my truck (keep in mind im bagging it) and i need to know what would be the best kind of steel to use, and how to weld it to the original frame
and anything else im missing here

http://www.cachassisworks.com/cac_how_to.html

The preformed backhalf framerails you buy are usually made from about 2 x 3 or 2 x 4 rectangular tubing with either a 1/8 or 3/16 thick wall. The most common plan is to cut off your old frame a few feet in front of the axle, then weld a crossmember going from side to side, bridging the cut off ends. This crossmember usually has a hoop welded into the center to let the driveshaft pass through. Then you weld the new rear frame sections to this crossmember, and add gussets to make it strong.

The new rear frame sections arch up and over the axle. You can fab up your own back half kit, but the ones they sell start at about $ 500.00 and a lot of the work is already done for you, and they are done on a jig for straightness.

Trucks are easier than cars most times, because you have all that empty bed to stick the big tires into.


Don

Make sure before you cut anything that the frame is tied down or in some way fastened to a sturdy table or chassis jig... With all the years of stress when you start cutting frame rails and body panels, things start moving around.. Not the type of mod you want to do with the car or truck setting on jackstands.

I've back-halfed more vehicles than I really want to remember........

If you follow some easy steps you will end up with a very neat, safe & fun to drive vehicle.

REMEMBER: Measure twice & cut once.

The following are the procedures I go thru to get my project under way:

1. Get the vehicle as far up into the air, on jackstands, as possible.

2. Level the vehicle - run a level in the door sill area - you can always go to it to make sure nothing has changed.

3. On the floor mark the front/rear axle center lines. This is VERY important as this is your old wheel base. Any adjustments can be made from that.

4. For a p/u truck after 1-3 are done remove the bed from the chassis. You'll be cutting & welding on the bed later.

5. Determine which rear "system" you will be using (4 link or ladder bar). As of late I have gone the 4 link way - much more adjustability + side to side indipendence.

6. Personally I'll cut a p/u 6-18" after the cab - depending on the ground clearence I'm looking for & what drop spindle I'll be utilizing up front.

** ALWAYS check rocker level**

7. After I've got all my needed tubing in hand I can now lay out a plan of attack.

You will need some outboard dims & tire dims to go forward from here.

You will also need to have the rear end you intend on using already cut down & wheels/tires mounted (unless you're real good) to get started.

OK........let me know when you get to this point.........

Plenty of people carry replacement frame rails.....find 1 & get it coming your way.

paco

Be sure to think about "airborne adventures" over railroad crossings and such. A bit of overstrengthening is a good thing.

airborne adventures hahaha
and this backhalf really isnt for racing or anything like that. its to help get my truck as low as possible. and backhalfs look alot beter IMO im considering just welding in a notch for the axle and putting a new frame from the notch back. it would clean it up and i dont like how the frame rails kind of taper in at the back

.....I got a chassis set up from Chris Alston once; frame rails, rear cross member, 4 link set up, shocks, etc & it came with really good directions...... Bill

Mute........

A "C" notch & air bag suspension is a lot easier but will not get the big skins up under the wheel wells.............but can be done at home with much less fab work.

regs