Straightening the front bumper

W

wrndln

Well-known member
I have a front bumper in good replated condition. However, it is bowed in about 1/2" inward. I don't know why the plating company didn't straighten it before replating, but they didn't. I believe bumpers are made of spring steel, so they would tend to return to the original bent inward position when straightening is attempted. Does anyone know a good way to straighten an original replated bumper?
Thank for any suggestions
Rusty Nelson
 
Is the bumper mounted on a car or not? It would need to be anchored to something solid with wood blocks to then be able to push or pull it back into shape. If I were doing it I would strap it down to the deck of my frame machine and use a port-a-power to push up the low spot until it was straight after springing back. However, most people don’t have a frame machine laying around. The deck of a 4 post lift would also work if you had access to one of them. Another option might be to set it up on wood blocks under a vehicle and use a bottle jack to push down on the high point in the bend. As long as you cushion the blocks with towels I would think the chrome would be fine.
 
Right now the bumper is on the car. However, it is easy to take it off. I don't have a frame machine or something like it.

Rusty
 
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If it is mounted to the car I’m wondering if the bow in the bars would come out when it’s unbolted. If the bow is in the center then it could be bent brackets holding tension on the bars. If that is the case you may be able to pull it out on the car. Do you have a hand winch and chain or strap? Ideally a canvas strap around the bumper and then attach the winch to another vehicle with a hitch or tow hook. Put a slight tension on the strap, loosen only one side bracket, increase tension on the strap until the bow is out, then retighten the bracket. If it still springs back then either the bumper needs to come off the car to be straightened or one of the brackets is really bent and will need addressing. Can you post a photo of the bumper bars and brackets? I’m only assuming that the bow is in the center at this point and a picture would help. Either way, the first thing I would do is loosen the bolts way up and see if it relaxes.
 
On potential issue could be that plating is not as flexible as the steel. And, generally not as “attached” as on new steel. The chrome could crack; just 1/2”, maybe not. But those are spring steel and moving it won’t be all that easy. If done on a press would have been much easier….as you know!!
Just words from a normal pessimist!
 
I’m certain it wouldn’t be the first one of these cars that was straightened on a tree. Just kind of embarrassing when your neighbors see you doing it.

The chrome is a concern being that it has been replated but 1/2” bow in a 5 foot length of steel really isn’t much. You’d likely need to bend it several inches past straight to get it to stay but it’s so gradual that I doubt it would hurt quality plating.
 
Thanks for the suggestions, everyone. The car is currently not running, as it is being restored, so the "tree" thing can't be done right now. I was thinking like Thodge stated, maybe the "clamping" to the bumper arms could make the inward bow worse. If I remember correctly, I think there was a slight bow before I mounted the bumper bars to the arms. One of the bumper bars is not bad, but the other one has the 1/2" bow mentioned earlier. I will remove the bumper bars from the arms and check if the bow is as much as when it was mounted.
Rusty
 
A large I-beam or a section of railroad track can be used with a bottle jack or jacks and heavy duty cargo strapping. The jack would likely need a heavy piece of wood to push against in order to spread out the load. I've straightened bent frame members this way. A large press works if a person knows a local fab shop that has one. A local body shop may have a frame machine. The use of chains would require something to pad the chrome.
 
Set it upside down on a couple of blocks.Then jack down on it.You will have to go a few inches beyond,you will do it a half dozen times until you get the feel for what you want to do.You have to get creative,you can jack from under your car,under a truck,trailer,in your cellar under a beam,really anything where the bumper goes downward when you jack,and what you are jacking down from doesn't go up.I have a nice press,but it is set up too close to the wall to get the bumper in it.So instead of digging it out and spinning it around,I took my friends bumper out and jacked it down under a backhoe.
 
Bill is correct. is it worth runing the chrome for 1/2 an inch?


kind of like touchup on a Renoir painting when you shouldnt...........
 
ronn said:
Bill is correct. is it worth runing the chrome for 1/2 an inch?


kind of like touchup on a Renoir painting when you shouldnt...........
Click to expand...


You most likely will do more damage trying to fix it.

I think RONN is saying to leave it alone. That would also be my recommendation.

If it isn’t broken, don’t try to fix it!

Enjoy.
 
It is not right, as is! It looks cheesy. I will try what Keith said. I don't think moving the bar 1/2" forward would damage the chrome.
Rusty
 
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I would take it back to the chrome plater's shop. They should have the equipment. I assume it was bent when you asked them to chrome it and you didn't tell them to straighten it? Off the car I understand why they might have missed it. I doubt anyone would notice it unless they were looking for it or happened to be at the right angle to see it.

Charlie Stephens
 
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My friend had a woman hook into his front bumper and pull it forward.She paid him very well for at,and he bought and installed a new bumper.I have a 35 ton lowbed,and found a spot under it where the blocks,the bumper,and a jack would fit.I really expected the chrome to rear up and peel off in slivers and sheets.It came out good,and is still on my car today.I expect bubbles and such to start,but it's only been on there for 10-12 years.I strongly suspect it is not really adhered to the metal,but is just wrapped around it and holding itself on,kind of like a condom.
 
Rusty, I notice you mention that only one of the bars has the bow in it. Maybe it doesn’t need to be straightened but just preloaded before the bumper clamp is tightened so it matches up with the other bar. Since it’s a spring, if it were preloaded with a slight outward bow it would want to spring back but would lengthen in the process. If the bumper clamps were securing the width, I would think it wouldn’t be able to bow backward. Sure, you’d have to repeat the process every time the bumper was removed but it’s not like you’re taking the bumper off every day.
 
I tried the chaining a Model "A" front bumper to a tree and it bent the bumper support arms instead of fixing the bumper. I think you should bring the bumper to a truck spring shop along with a sketch of what it should look like and the shop reform it.
 
Mount it and tighten it up and see what it looks like then adjust your corrective bend accordingly, You might over correct and have the opposite bend later.
 
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