Tailgate bend

reallylongnickname

reallylongnickname

Promoted Users
There was a plate of steel welded on this tail gate from the past. Who everwelded it, warped it by welding too quickly. I placed a crow bar to show how much the bend is.

Anyway, should I bring this to a shop to try and straighten it? Not sure a backyard attempt will work. Would seem a lot of even heat would be needed to attempt to straighten it.


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I’m guessing the steel plate was welded on to it because it was bent. Welding it wouldn’t warp it like that.

I had a body instructor who straightened a bent tailgate like that. He laid it on the ground with the curved side up, put a board over it and jumped on it.
 
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It appears the plate was welded to the side presently facing up in your picture, with the lower weld being along the edge where the paint stops. If this was welded without planishing (near impossible to planish so no doubt what happened) the inner part of the tailgate along the weld would shrink in length and the outer part would remain constant. This would indeed result in the bow that you are showing. Welding speed had nothing to do with it, weld shrinking did.
 
Is that tailgate one big stamped piece, or is it a skin over a frame? I think it's worth saving if it can be done.
 
I have used my front end loader to straighten things like that. Support the ends with the curve up and gently push down with the loader. Sometimes a blanket is used to cushion the part. Depends on the part. That tailgate I would straighten top and bottom separately.

Don
 
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Lizer said:
I’m guessing the steel plate was welded on to it because it was bent. Welding it wouldn’t warp it like that.

I had a body instructor who straightened a bent tailgate like that. He laid it on the ground with the curved side up, put a board over it and jumped on it.
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Youd be guessing wrong. The plate was put over because of camper was added. The camper is the reason the tail gate is perfectly preserved aside from the bend that was created. Standing on it, would strength the metal causing potentially to no fit.
 
reallylongnickname said:
It's very mush worth saving. Other than the bend, it's perfect. One stamped piece. Dodge made good stuff way back when
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the 80s fleetside gates are usually warped too. i havent found a good way to straighten them, but you might that one since its basically a flat sheet.
i wonder if you could rig up a jig in a good size press. not that you need much power but the control would be good. i am betting youll have to go past straight so it springs back straight.
 
The picture illustrates a fundamental welding issue that many people are not aware of. The puddle side of welding will typically be wider and melt more filler/parent metal than the penetration side --that often ends up being a "V" or rounded "U" shape at the bottom in such a lap weld with the plate being thicker than the tailgate material. I cut and etch hundreds of welds a year and look at the cross sections under a 10X comparator. Consequently, initial thermal expansion of the plate heated from welding had no where to go if it was "all tacked up" before welding or skip welding to keep it in place during welding and it grew in length by bowing down. This is separate from the weld shrinkage problem that happened. Weld shrinkage greater on this side where welding was initiated than on the back side. That's why it bows down not up.

If it were me--I'd remove that plate by grinding off the welds first--see if any elastic movement is there--unlikely. If the outside skin is convex--I would take a good heavy piece of steel flat-bar and grease the outside contact points near the trunnion supports to allow the gate to slide on this or a piece of UHMW between the gate and the steel if pressing is attempted. you might have to heat on the concave side by the trunnions to orange heat right before you attempt to press. If that doesn't get it all--oxyacetylene heat to a orange heat spot the very outside skin where the trunnions are and see if that pull in shrink will contract the elongated outside skin back to being flat on the outside. Careful is the word here--how much depends on what's left. I'd try a dime spot first or less alternating sides quickly. Let those cool and see if you can gain anything --if so--heat and cool again and see what more flattens out.
 
I had a tailgate that looked similar to that. I placed a piece of plywood on the driveway big enough to protect the top of the tailgate from contacting the concrete. Laid it on the plywood and then put a 2x6 over the bend and with someone guiding me I drove the front wheel of my truck over the 2x6.

That took most of the bend out, then I added 1/4" thick blocking under each end of the tailgate and repeated the drive over. It came out almost perfectly straight.

Certainly not the best way to go about it but it worked for me.
 
Last old Dodge gate I did I took to a shop that had a press brake and they got the bend out for me. Certainly the added on metal should come off first.
 
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