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Frame broke AGAIN around the steering box

zcarczar

zcarczar

1/2 ton status
Joined
Feb 10, 2002
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Location
Apple Valley California
I had broken my frame about 6 months ago and added the weld in brace to fix it, all has been fine till I went and ran Clawhammer, truck started making wierd noises when turning and steering had more slop that usual. Sooo I looked at it today and the freaking frame broke AGAIN! My frame had some made flex going on too, so I added a cross member and it seemed to have helped it some and I welded up the cracks as best I could because I only had 45 minutes to fix it.

I outlined hte cracks with the black lines, those were the only ones I could see, so Im sure there is more.

acv.jpg


Here is the crossmember I made.

acu.jpg
 
/forums/images/graemlins/yikes.gif /forums/images/graemlins/eek.gif ouch must really be flexin up there. Do you have hydro-assist?
 
Did you stop drill the previous cracks before you welded them up? I only ask because it sort of looks like the one crack picks up where the weld has stopped. I think you can buy some magnaflux and a blacklight and look for hard to find cracks. You may have missed a hairline crack before.
 
Ouch /forums/images/graemlins/weld.gif Nice looking crossmember, looks stout enough.

That looks like mine right now. I am getting ready to add a custom crossmember to mine and weld up my broken frame too. Shane74 and T-roy are nice enough to lend their design and welding skills and fix me up /forums/images/graemlins/woot.gif I'll of course show pics when its all done.
 
That sucks. /forums/images/graemlins/yikes.gif I guess it's time to get to work on boxing the other frame and do a swap.
 
No bolt on brace, I have the factory oil cooler so the lines are right in the way of were the brace needs to go.

The cracks were on the outside face of the frame before these cracks started, so I doubt they are from teh same one.

The crossmember I made is just a piece of 2x2x.120 welded in, its attatched to both sides of the frame and pushed as far down as possible and welded to the bottom of the frame. It stopped a lot of frame flex but the frame still flex's waaayyy too much for my liking. I will be fixing that on the new frame im gonna be building
 
I don't know that's such a good idea. All that stiffness is the reason it cracked again. You can keep trying to make it stiffer, but it is engineered to flex, and without flex, it will continue to crack.
 
I understand that, but when something flex's too much it also fatiques the steel and will cause it to crack. Look at a rollcage that isnt designed right and flex's, eventually it will crack and fail when it is stressed. Same Idea with the frame. If you eliminate 99% of frame flex your not going to have the problem of cracking frames like everyone else does. Look at the new trucks, most of hte new truck are running fully boxed frames, Hence the reason why my new frame will also be fully boxed. /forums/images/graemlins/thinking.gif
 
Could it have been caused by the 52's up front? /forums/images/graemlins/thinking.gif
 
[ QUOTE ]
I understand that, but when something flex's too much it also fatiques the steel and will cause it to crack. Look at a rollcage that isnt designed right and flex's, eventually it will crack and fail when it is stressed. Same Idea with the frame. If you eliminate 99% of frame flex your not going to have the problem of cracking frames like everyone else does. Look at the new trucks, most of hte new truck are running fully boxed frames, Hence the reason why my new frame will also be fully boxed. /forums/images/graemlins/thinking.gif

[/ QUOTE ]

No matter what you do, you're not going to eliminate 99% of the frame flex anyway. I'd bet you can cut it by 60-70% or more, but if you could nearly eliminate it by simply boxing your frame, the OEM wouldn't be spending the big dollars on things like hydroformed rails.

Boxing it completely seems like a good idea to me, but it's not going to be the end-all to your problems like you seem to think (at least I don't think so).

To completely eliminate or seriously reduce frame flex you're going to have to do something in more than two dimensions (like tie a cage into the frame at a number of points) and that opens up a whole new can of worms.

I'm going to let my frame flex until the seams of the body come apart. It seems to stay together just fine that way.
 
I don't believe the 52's are at fault here. I would think a stiffer spring would put more of a impact on the mounting set then a softer spring. It's a combo of parts. chevy's steering box mounting design, crossover steering, tire size. If you can tone down the leverage the box as on the frame thats the key. best way it to capture the two bolts cdloser to the firwall and brace them into the frame rail and/or the front crossmember.
 
You can use the bolt in brace with the factory oil cooler line. Many here have. /forums/images/graemlins/thumb.gif
 
[ QUOTE ]
I understand that, but when something flex's too much it also fatiques the steel and will cause it to crack. Look at a rollcage that isnt designed right and flex's, eventually it will crack and fail when it is stressed. Same Idea with the frame. If you eliminate 99% of frame flex your not going to have the problem of cracking frames like everyone else does. Look at the new trucks, most of hte new truck are running fully boxed frames, Hence the reason why my new frame will also be fully boxed. /forums/images/graemlins/thinking.gif

[/ QUOTE ]

My opinions on frame stiffening are well known, so I won't go into that again here. However, the fatigue cracks you mention are due to localized flex and resulting stress. When the frame can flex along it's length, there is no problem. But when a flexy part of the frame meets a rigid part, it will crack. It’s not a question of if it will crack, but rather when it will crack. That's exactly why the frames crack around the steering box as it is. The steering box works against the frame with a stress riser right around the rigid area formed by the bolt pattern on the structurally rigid steering box casting. The frame tries to twist one way, but the rigid cast steering box wants to go another. The bridge braces help by reducing the steering box ability to move independently, restrained only by the frame rail vertical wall. It's basically using leverage to make the steering box move *more* with the frame. Still not perfect, but it does increase longevity by a considerable margin.
 
Well my frame is flexing enough to cause my front fenders to rip out the spot welds and the body is beginning to basically fall apart. Also my buddy who was in TTC 2k3 destroyed a stock frame like I am beginning to. So he took a stock frame and fully boxed it and added a roll cage. He hasnt had ANY frame problems what so ever, and when he flexes the truck up the springs do all of the work, not the frame.

Baddog, Ive seen your thoughts on a fully boxed frame. If I wasnt going to fully box it I wouldnt even entertain the idea of boxing it partially because then it does create a giant stress riser in the frame if not done properly.
 
Good plan, sounds like we are in complete agreement. I have no problem or concerns with fully boxing the frame (other than thinking it's more work than it's worth). It's those half done or partially boxed attempts along with "tie the cage in to make it rigid" or "weld on some random pieces of plate" that worry me...

As for breaking the body, that can be dealt with other than fully boxing the frame. I’ve seen some center mount (pivots) work very successfully in that regard.

In any case, good luck.
 
chev frames are simply total junk
other manufacturers have the same steering box rigidity but manage to keep the box on the frame
the Dodge is practically a carbon copy of a Chev
do they have a thousands threads on steering box falling off the frame?

on boxing the frame, this may work for you desert dwellers but every vehicle with a boxed frame fails to survive for long in our climate
you cannot buy a toyota 4x4 here that doesnt have the frame rotted out from under it
same with EB, scouts etc
once the silt/salt/mud gets trapped in the box the gig is up
so be sure to allow voids for debris to be cleaned out if you plan on trying boxing
 
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