too much frame and body flex

[vortec]

i've seen some of these older trucks pop the body to frame mounts by flexing too much. what is a reasonable amount for the body to flex in relation to the frame, without being concerned about this (pics, maybe)? i was thinking about beefing up the mounting points. i've seen some posts on here that touched on this, but weren't specifically about how much is acceptable.

 

[Boondocks]

I just saw a blurb in the current 4-wheeler mag, that shows a setup where the underside of the body mount point on the frame had a piece of overload coil installed over a piece of pipe (guide). This allows the body mount to seperate from the chassis under spring tension and hence more chassis flex without the body flex.

Comment was that this prevented flex related body cracks. It didn't mention any additional artriculation.

 

[dyeager535]

Beefing up the mounting points won't work IMO.

The body is not rigid enough to hold the frame solid, and the frame isn't solid enough to hold the body straight.

Boxing the frame, or full cage, and additional/better crossmembers would greatly reduce the problem.

If you strengthen ONLY the body mount points, you will induce failure where the strengthening ends, such as the sheet metal that the mounts are welded to, or the frame, likely between the mounts.

I experienced this when switching from rubber to poly body mounts. Poly seemed to make the problem no better, if not worse, which if the body was rigid enough to keep the frame from flexing, would not have been the case. If anything, rubber lets the body move a bit more which allows the body to stay a hair more intact when flexing, while the frame takes more of the abuse.

 

[nickdubrule41]

i also read that article on the yellow burb. it seems like it would be exactly what you are looking for. it was cool how he made that up with a piece of a helper spring exhaust pipe and a custom plate welded over the old body mount bracket.i have the mag in my living room if you want more info on it just ask.

 

[drofdar]

Body Mount

Anybody know what torque should be used on the mounts, and could a two tight mount be part of the problem?

 

[Russell]

My book calls for 85 foot pounds for the body mounts.

 

[jrpeebles]

The desert crowd eliminates all frame and body flex by building bumper to bumper cages, using solid body mounts, and then by welding the body to the rollcage with metal plating. Obviously their goals are a little different than most people on this board, but it might be a reasonable option. I am going this route in my fullsize longbed because I am getting tired of the cab tring to tear itself apart while wheeling.

 

[vortec]

hmm. some good ideas here. maybe i'll try some after my engine actually runs again. i think a rod broke, but digging into my 23 year old engine to be sure has proven to be a real PITA. off topic there.