Twiztedmods
1/2 ton status
Went out wheeling yesterday and I noticed the frame flexed more then I wanted. Is this a huge issue? How do I reduce the frame flex?
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Crazy frame flex! How do I fix this?
- Thread starter Twiztedmods
- Start date
Extra cross members will help make sure the rivets in your current ones aren't loose. Boxing the frame is next. 2 largest improvements I have ever seen have been welded on sliders ( to the frame) acts like a huge outboard crossmember and a cage attached to the frame.
No plan for a cage ? Then adding well thought out crossmembers and boxing is where you need to be going
No plan for a cage ? Then adding well thought out crossmembers and boxing is where you need to be going
Body mounts shot?
Twiztedmods
1/2 ton status
I am in need of some sliders and I do plan to cage it this year. It sure was a challenge wheeling a full size Blazer at Corral Canyon.
dahreno
Registered Member
In my old Willys wagon the frame would flex so much I couldn't open the doors.My new wagon is on a k5 frame and it is much stronger.If I have a flex problem I will box the frame,I will be adding sliders first anyway.
Twiztedmods
1/2 ton status
I definitely like the idea of boxing the frame. I just need room to pull the body off. Are you guys boxing the whole frame?
Fair number of threads on frame flex/solutions. If boxing, you have to do the whole thing or it cracks where you stop. Boxing alone won't do much, more/better crossmembers are needed (which is pretty tough to do well based on the drivetrain layout) but as has already been said, a cage is the ultimate, especially if you are planning to go that route anyway.
Not certain, but I expect with a cage, boxing is far less important, and if planning to cage it, I'd do nothing else unless I absolutely had to for some reason.
I'm not going to run a cage, and don't wheel hard, but want the suspension to do the work, not the frame, so I'll box and modify/add crossmembers as I can.
Not certain, but I expect with a cage, boxing is far less important, and if planning to cage it, I'd do nothing else unless I absolutely had to for some reason.
I'm not going to run a cage, and don't wheel hard, but want the suspension to do the work, not the frame, so I'll box and modify/add crossmembers as I can.
Looks like you have bad body mounts
I would definitely do body mounts. This is what mine looked like before I did mine
Is it really bothering anything?
Martin
Martin
72blazerguy
3/4 ton status
A cage will help a bunch. I used to not be able to open the doors on my 71 when it was barely flexed, added a cage and the problems went away.
Twiztedmods
1/2 ton status
Thanks for all your inputs. Looks like I will be replace my body mounts.
Stomis
Professional Amateur
Not trying to be a jerk but how do you figure the frame will crack if you stop boxing it half way through? Lots of factory frames were weld boxed from the factory including GMT400s and stopped at or just past the fire wall.
All you have to do is not abruptly end the boxing like so:
As already determined though OP it certainly looks like your front mounts are pulling right through the frame bracket.
In the past here I'd seen advice given not to box part way. I don't know as I'd seen actual failures related to partial boxing, then again I don't recall many/any people go that route either...usually it's either none or all.
In my thinking, if an 18' chunk of steel is under enough load to flex, and you reinforce part of it, if there is still substantial load on the unboxed portion(s), the steel will flex up until the reinforcement, which is where problems may occur. Additionally, if you reinforce/add crossmembers, but don't box around those areas (which gets to the point where there would be nowhere left unboxed) then you are probably inducing another stress area. Obviously at either extreme end of the truck, past the leaf spring mounts, boxing probably isn't necessary at all.
I don't have a ton of newer frames to look at, but from what I saw of "selling points" of GM's newer frames, they are rolling a lip into the C-channel to increase rigidity, but still reduce mass. http://lh6.ggpht.com/_jM4_z6E48dY/SncWiGwC_9I/AAAAAAAABR0/VHFVuFLapUs/s800/Picture%20069.jpg Looks to me like the change to IFS, better design, and perhaps increased motor output drives/allows the boxing of the forward portion: http://www.tonkinonlineparts.com/images/parts/gm/fullsize/110718TK07-004.JPG
In the OP's case, "fixing" the body mounts means you are now expecting the body to control all of that flex that it now exhibits. The body is nowhere near strong enough to do what is asked of it with a stock frame, thus broken hard top seams, popping roof panels, and impossible to open doors, even with very mild off-road use.
In my thinking, if an 18' chunk of steel is under enough load to flex, and you reinforce part of it, if there is still substantial load on the unboxed portion(s), the steel will flex up until the reinforcement, which is where problems may occur. Additionally, if you reinforce/add crossmembers, but don't box around those areas (which gets to the point where there would be nowhere left unboxed) then you are probably inducing another stress area. Obviously at either extreme end of the truck, past the leaf spring mounts, boxing probably isn't necessary at all.
I don't have a ton of newer frames to look at, but from what I saw of "selling points" of GM's newer frames, they are rolling a lip into the C-channel to increase rigidity, but still reduce mass. http://lh6.ggpht.com/_jM4_z6E48dY/SncWiGwC_9I/AAAAAAAABR0/VHFVuFLapUs/s800/Picture%20069.jpg Looks to me like the change to IFS, better design, and perhaps increased motor output drives/allows the boxing of the forward portion: http://www.tonkinonlineparts.com/images/parts/gm/fullsize/110718TK07-004.JPG
In the OP's case, "fixing" the body mounts means you are now expecting the body to control all of that flex that it now exhibits. The body is nowhere near strong enough to do what is asked of it with a stock frame, thus broken hard top seams, popping roof panels, and impossible to open doors, even with very mild off-road use.
While the idea of partial boxing leading to frame cracking seems logical it just doesn't play out like that. Mine hasn't broken yet and I know several others done similar to mine that haven't either. That said it makes more sense if your gonna box it do it all the way.
Went out wheeling yesterday and I noticed the frame flexed more then I wanted. Is this a huge issue? How do I reduce the frame flex?
Attached Thumbnails http://coloradok5.com/forums/attachment.php?attachmentid=154767&d=1390154562
Not to get off topic but I spy a scout
And Ill agree that it looks like your body mounts are shot and pulling through the frame. I had one that did that, caused the fan to hit the shroud and my transmission linkage to shift gears for me. Nothing quite like climbing a big hill and suddenly hitting reverse
Boxing the frame and building a cage that attaches to the frame are both good ways to get rid of frame flex but are both involved and a lot of work. If I were you Id start with fixing the body mounts and see how that works out unless you are ready for a big project.
Twiztedmods
1/2 ton status
You are correct, that's my buddies 67 Scout. 
Cage and really squishy suspension.
Wait, the suspension is supposed to do work on these trucks? lol
I like how the bumper is still aligned with the front end.
No roof popping/hard to open doors?
I like how the bumper is still aligned with the front end.
No roof popping/hard to open doors?
Twiztedmods
1/2 ton status
I like it!
