frame reinforcement on A3 4x4 project

Adding frame reinforcement that will be 3" below the existing plate for using m105 spring and mount. It's 10' so will go to just behind the cab and tie into ROPS/top/winch mount frame. New piece laps to top of frame and is 11x3x1/4"x10'.

During a torsion load on the frame (eg. twisting while off-road) won't that concentrate stress at the ends where the stronger part joins the existing frame?

Also, if you're putting that much more weight on the back of the truck, wouldn't a set of deuce front springs be a better choice than 1.5 ton M105 springs?

Pictures of the deuce front spring and the m105. They are the same width and leaf thickness. The 105 has same number of leafs plus the overloads.

I want the extra width on the frame mount to axle of the 105 too.

If I were into extreme twisting, it may indeed transfer enough stress to crack the weakest point. I'm not building it for that use, however. My 73 boomtruck has the same frame reinforcement and no signs of cracking at all.

Note in the above photo, the steel L will be added to the side and be 3" lower than the present frame, it will not be mounted where it is in the photo on top.

Removed the bumperette and making a new, lower, rear bumper from 2 x 6 x 3/8". It will bolt on the frame and weld to the reinforcement plate at the back that you can see in the photo. Will make the bumper assembly and set it aside so axles can come out, not have a rear bumper in the way.

edit. Added photo with mount for pipe crane jib attachment points and bumper position.

Cleaning off the sides of the frame. I had a big rust pocket under the left trunnion reinforcement plate that cleaned up with some grinding. Next off the tank and trunnion.

Looks good. I was planning to bob mine, but went full on now, with a crew cab under construction. The 105 springs will do fine, they have more capacity than the front with overload. I am sure you've seen the xm381 bob links online. I was just following that until my wife found a crew cab pic and that was it for mine.

Hi jkcondrey. Yes I followed several and made some comments about my planning for this project(s) on a couple threads. I'm making a trailer from the cargo bed, so have post on what I did to my trailer also.

Post up a ink to your crew cab build, if you have one. That is a big change to make + 4x4.

I concluded I wanted full frame length and went back and forth on the bed, coming back to the M105 for a 4x4. What I build in the space from the cab back to the bed can be (length) adjusted.

Decision now is fitting the 105 bed, which I don't have yet, exactly in the right position that matches my; 1 frame and; 2 tail gate when lowered vs. pintle hitch and; 3 axle is centered on the wheel well.

My M105 drawing shows an inside length of 110". I need to confirm every inside and outside dimension to make the location. I want the rear gate to go down, fully vertical and just touch the pintle. Hopefully someone with M105 detail pictures will post up a few and take a few measurements. I specifically need a profile where the gate is fully down.

Since my pintle is fixed, the back of the bed has to be even with the end of the pintle. That then determines where the wheel well is located and thus the center of the axle and placement of spring mounts.