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Frame Flex...how much is too much?

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PhilS10HO

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It seems a lot of my flex is from the frame. 87 1/2 pick up. It's got 10+ year old 4" springs in the front. Stockers in the rear on blocks. Seeing the front bumper and body lines so out offline is an odd feeling. I'm not overly concerned just want to know what's normal for these trucks. Thanks
Phil
 
PhilS10HO said:
It seems a lot of my flex is from the frame. 87 1/2 pick up. It's got 10+ year old 4" springs in the front. Stockers in the rear on blocks. Seeing the front bumper and body lines so out offline is an odd feeling. I'm not overly concerned just want to know what's normal for these trucks. Thanks
Phil
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check your body mounts, i get the same thing, and a bad front/right mount is the cause:crazy:
 
PhilS10HO said:
Is there a chance of any kind of damage running it that way?
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i dont think so....nothing wrong with a little flex in the body...
 
over time the stress will cause cracks in the frame. A riveted frame is designed to flex, but only to a certain extent. The reason people have their steering box rip off is because the frame flexes in that area. that is only one example of a failure that can happen. I have seen frames crack through the front shackle mount.

You want your suspension to do the flexing. make sure all your body mounts are tight. the longer a frame the more visible the flex. so if you have a long bed then it will look more out of whack then a blazer. the one piece bodies of blazers and suburban's fight flex slightly more then trucks.
 
my front body mounts used to be loose. the body would lift up off the frame every time it flexed. it would allow the frame to flex enough to do funny things to my shifting linkage. after it caused the transmission to kick into reverse and shoot me backwards down a hill I was trying to climb I decided to fix it. replaced body mounts and the metal plates and cups and it made all the difference in the world.
 
Okay,

Not trying to hi-jack the thread, but how do you know if you have flex issues. This being my first Chevy, there is no body lift, just suspension and not an ounce of rust anywhere on the frame. The rig is Texas born, Texas bred, Texas lived and Texas will die. Anyway, as a precautionary, I've been thinking of having all the body mounts welded over and of course, the frame strengthened at the steering box for my conversion to cross over. So, to parallel my friends post, is that enough, or are there other areas to consider to tighten up a 24 year old frame.

Thanks!

Manny
 
gmc4cw said:
so if you have a long bed then it will look more out of whack then a blazer. the one piece bodies of blazers and suburban's fight flex slightly more then trucks.
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Yes I have a reg cab long bed.
 
What about boxing the frame? Would the pro's outweigh the con's doing that? I have a LOT of chassis flex also but good body mounts. My bed put a softball sized dent in the back of my cab trying to get out of a bad hole on Pritchet @BB this year. I hammered on it harder than ever when the cab dent happened. Not trying to hijack just sounds like the same problem. I am willing to box it if its worth it.
 
JpEater said:
What about boxing the frame? Would the pro's outweigh the con's doing that? I have a LOT of chassis flex also but good body mounts. My bed put a softball sized dent in the back of my cab trying to get out of a bad hole on Pritchet @BB this year. I hammered on it harder than ever when the cab dent happened. Not trying to hijack just sounds like the same problem. I am willing to box it if its worth it.
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Id say the pros would outweigh the cons. Would there be any other mentionable cons aside from the cost, some added weight, and work involved? The work involved isn't a big factor IMO...most of us are more than willing to put hr after hr into our trucks...

Trey, do you have sliders on that truck? those obvously would help SOME...Adding crossmembers would help too. I know our trucks lack those a lot. You will never be able to eliminate all the frame flex, but its not hard to eliminate a good chunk of it relatively cheap and easy...
 
Its a lot of work but Ive heard that removing all the rivets in the frame and replacing them with bolts and washers will reduce frame flex.
 
In general, i'd say if you were to box the frame, do all or nothing. Some will fight me on this, but if you stregnthen one part, it will just break(or flex) at the next weakest link.

This wouldn't apply to a small area like around the steering box, i just mean don't box just the front or just the back.
 
There is a difference in the frame flex on a Blazer and on a Truck. I don't think that adding a crossmember would do a lot of good because it would cause a new stress point. I don't want to add rock sliders because I have so much frame flex that It would break the mounts or the frame at the mounting points, and I think that they would contact the bed or cab at full articulation. Thats why I am asking those that have done it is it worth the work to box it front to back?
 
Boxing the frame at the steering box is worth the effort. If you do it you should sleeve the mounting holes for the box. if you just run a bolt through then the forces on the box can collapse the boxing and loosen the bolts.

adding a crossmember does add a stress point. you are thinking about it wrong though. If you have 5 crossmembers now, then the flex is shared over 5 points. if you add a crossmember then the stress is shared over six ponts.

If you want to build a stiff chassis then use tubular crossmembers and a boxed frame. look at the difference between a wood ladder and an aluminum one. the wood ones are similar to our frames. the steps are flat like our crossmembers.

some of the things you need to work around when boxing the frame are. moving the brake and fuel lines. modifying the crossmember mounts. changing the front shackle mount.
 
I got rid of my frame flex by getting a 12 point roll cage installed and tied to the frame or suspension points.

Cage57.jpg


Cage59.jpg

Cage54.jpg

Cage55.jpg

Cage56.jpg

Wheeling9-30-06007.jpg

Wheeling9-30-06018.jpg
 
that is sweet! what does the rear center point tie into under the body? did you taper the cage in at the back for a future body taper job? how much weight did that add?
 
I also have a cross member that ties my sliders together. They are mounted to the frame and the crossmember is mounted to them. I
 
gmc4cw said:
that is sweet! what does the rear center point tie into under the body? did you taper the cage in at the back for a future body taper job? how much weight did that add?
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The very rear cage point ties to my DIY4x4 shackle flip bracket. We intentionally did not taper the cage for future body work, but turned out to where it will happen in the future. As for the weight, I have no clue. We used somewhere around 300' of 1 3/4" .120 wall DOM tubing. Don't think I really added to much extra weight, with me losing the top, half cab, doors, tailgate, and factory seats everything should have equaled back out.
 
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