Fixing the rear frame while maintaining deproach angle... (1 Viewer)

[ridgerunner]

The PO of my truck did something rather inovative with this 55; he cut the rear frame rails and "Z'd" them up for a better departure angle. Compared to my other pig which dragged ass all the time, I love the 1.5" or so of the gained deproach. However, there's a few things I'd like to do with the rear end here in a few months when I have the chance to work on it:

1) I'd like to straighten the rails. Currently they're a little / or \ ever so slightly, and the repressed perfectionist in me would like them straight. Plus it would give me a chance to clean up some of the welds.

2) I'd like to box the rails all the way to the bumper. This should add significant strength (watching the spare tire bounce around is rather disconcerting) while not adding much more weight.

For the amount of work required though, and since I plan to be replacing the body with a non cut truck I currently have, is it more worth while to cut some frame rails off another pig and replace them or to use these? I'm not a fan of the butt welded rails, and am worried about strength; think boxing would cure that?

Thanks, and I apologize for any confusion!

 

[usmcruiser]

you should take a look at what dieselcruiserhead did with his 80 frame in his "Biodiesel Piggie #2 Buildup (was Sad Sad day...)" thread. He now has a very strong frame after splicing it. You could do somthing simmilar.

 

[LC_Hamma]

Sounds like a great idea to me: https://forum.ih8mud.com/showthread.php?t=76835&page=2

 

[ridgerunner]

you should take a look at what dieselcruiserhead did with his 80 frame in his "Biodiesel Piggie #2 Buildup (was Sad Sad day...)" thread. He now has a very strong frame after splicing it. You could do somthing simmilar.

I saw Andre's work on his pig, and am impatiently awaiting the next installment. I'd like to keep the weight down as well though, which is why I'd like to do something other than butt weld the frame together.

Chuck- how much clearance did the "sectioning" net you? I like this idea, however I'd have to do something different for spring mounts and I'm not sure my gas tank would be too happy (at 35 gallons, I'm don't want to go searching for a new one).

 

[Gumby]

Andre's joint was built to support the truck, and well done. To support the body back of the wheel wells you could just fish plate the frame and do fine.

If you want to tow off of the rear bumper, however...

 

[ridgerunner]

If you want to tow off of the rear bumper, however...

Exactly.

Edit: I was looking and Jack Rice's truggy build as well, and he ended up sleeving the frame all around not unlike Andre's setup.

The question now remains as to keep the Z design or to move the frame section up like Chuck's so the frame is still relatively straight.

 

[usmcruiser]

Are you hell bent on keeping the Z design? What you could do is just angle the frame up like Chuck did. With the departue angle as bad as it is on a pig I wouldn't think that the extra 4 inches horizontally you gain would help that much. Plus with a gradual slope to the rear it could provide a better "ramp" to have the ass end slide off with. And another benifit is that you have one less weld on your frame thus there is less worry about every weld being 100% at every joint.

 

[LC_Hamma]

I'm kinda anal about how close to perfect I can modify my rigs. How outta whack is the rear frame? Only the PO knows if he got adequate penetration of those buttwelds. Fishmouthing the ends & plating over is the *proper way to adjoin those rear sections. I would source a decent rear frame from another PIG & start over. Also the stresses in those joints will fatigue more easily than a continuous bend (like I did on mine). I don't see why you'd have to source a new tank unless you bobbed it like I did. Lastly, I think I gained ~5" from the frame mod. It doesn't seem like much, but I had to add a 2" body lift to get the body leveled out @ the rear.

 

[KliersLC]

FWIW, Forest autoparts in Lewiston has several junk pigs.....

Stop by if you need any help.

Dan

 

[ridgerunner]

At this point, I'm not sure what I'm going to do. I would simply add a whole length of frame from another 55 to extend to the back bumper, but there's no section on a 55 frame that actually extends as far enough (since the middle of the frame is 5" as opposed to the ends of the frame only being 4") to the rear bumper.

I went back out and looked at the frame; the left is fine, whereas the right is tweeked maybe 1-2mm off (not as bad as I thought). I had a second idea: after making sure the welds fully penetrated the outside of the rails, take some 1x1/4" strap and weld some stringers inside the frame in an X pattern across the cut areas. Then box the inside of the frame rails, and plate the outside.

The reinforcement stringers (for a lack of a better word) are in red. (and yeah, I mastered MS Paint! Alright!)