View Full Version : straighten a bumper

10-29-2009, 05:23 PM
Looking for a way to straighten a bumper... Got an old shoebox rear bumper which has a natural curve to it...I want to put it on another project that has a staright rear pan... Got any clue how to do it right or a shop that does that stuff

10-29-2009, 05:30 PM
I would also like to know if there is an easy way to do this. I have a couple bumpers that need fixing.

10-29-2009, 05:40 PM
Looking for a way to straighten a bumper... Got an old shoebox rear bumper which has a natural curve to it...I want to put it on another project that has a staright rear pan... Got any clue how to do it right or a shop that does that stuff
Barry Back when bumpers were made of steel every large town had at lest one bumper exchange shop that fixed and rechromed bumpers maybe you can still find one that does .i used houston bumper exchange for years.

10-29-2009, 05:49 PM
A tree and a chain

10-29-2009, 05:50 PM
As a former bodyman, I can say that straightening a bumper depends on how it is bent. I the bumper is twisted, straighten by chaining the high point of the bumper to the ground, then jack up the car near the bumper mount. Pulling out a bend at the end of a bumper is done with a lever type tool, bodyshops ordinarily have the tool.
Try a local bodyshop for their opinion. As Texasred mentioned, most larger towns have bumper repair companys that primarily service bodyshops. The term for a bumper shop is usually "Rechromer" as they will fix a bent bumper then rechrome it. Its surprising how much damage can be repaired by a bumper shop.

10-29-2009, 05:52 PM
Any more finding a bumper shop that can straighten and re chrome yours is like finding a "real sheet metal man" they are out there somewhere its just hooking up with them.

10-29-2009, 05:57 PM
Ah guys thanks... actually maybe I didn't make it clear... a rear shoebox bumper has a curve or maybe you'd call it an arc.. I said bend but it's a curve... and I'd like to get it straight to fit the pan I got...

10-29-2009, 05:59 PM
There is a place in Grand Rapids, MI called Keystone Automotive that still straightens and rechromes steel bumpers. 90% of there business is plating new bumpers, so the wait on custom work will be multiple months, but their plating quality is second to none. We have used them to straighten some really tweaked bumpers before. We usually do our own straightening though so it has been a few years.

BTW, flattening out a naturally curved bumper will require a lot of careful force, like a hydraulic press. Some relief cuts will likely be in order to prevent folding/wrinkling/creasing. Sounds like a lot of work. Not something I would want to tackle. nor do I know of any place that would. I would check out some high end fabricators and ask what they think.

10-29-2009, 06:21 PM
Fill it in and make it straight.

10-29-2009, 06:53 PM
A tree and a chain

Ha ha that's what I used when a UPS truck hit the back of my F-150 !!

10-29-2009, 09:05 PM
I guess the easiest way to take the curve out of the bumper is to stretch the rear upper and lower edges. I would have the bumper stripped of chrome first so it doesn't crack and fly off. Chrome can be as sharp as razor blades, so get it down to bare metal.

Then to stretch it you have two ways to go at it. If you have a stretcher go along the edge and slowly stretch the edge. The bumpers heavy stuff so you'll get little reaction from the stretcher. the other way is to heat the edge. A little at a time and see what it does. The heat should cause the edge to expand, this will straighten out the bumper also. Your going to have to control the heat and watch the way it reacts. It may scare you as the bumper may want to twist as your heating it. But if you work back and forth between the top and bottom edges you should be able to keep it straight. Another idea came to me, it you know someone with a power hammer he should be able to stretch the edge and have alot better control.

Hope this helps: The Old Tinbasher

10-29-2009, 09:57 PM
Hmnnn, so tell your bumper guy it used to be straight, but you tried to sneak down a narrow alley and bent it in an arc when it caught on both sides. He'll be glad to take your money either way.

10-29-2009, 10:10 PM
Because I have to cut a section out to narrow the bumper some I'm thinking someone with a bid ass press might be able to straighten it, that and a bit of heat to soften it up a bit maybe... what ya think?

10-29-2009, 10:12 PM
So you want to change the original shape of the bumper, not fix damage on it. I have a feeling that would be extra difficult to do. Would it look wrong to make a new pan to match the curve of the bumper instead of making the bumper fit the flatness of the pan?

10-29-2009, 10:14 PM
No the pan is already made lights cut out and pan welded in....

10-29-2009, 10:40 PM
Not an option to remake the pan?

Streching the upper and lower edges as Tinbasher described. Heat will cause it to shrink though, not stretch. (Ok it will expand with the heat on it, but will return to a shrunken state on cooling)
Using heat to soften and aid in stretching may be you only option though on something that thick, unless you have access to a power hammer or e-wheel ( and then you still need the be able to fit the bumper in the machine)
Setting up a post dolly/anvil and hammering with a sledge would probably work, but you'd want to work carefully and be prepared to sweat a little.....

10-29-2009, 11:01 PM
I think it would be easier to start with a new peice of 11 gage. Make a template of the profile you want and take it to a shop with a press brake.

10-30-2009, 03:13 AM
I've seen some old bumper straighteners perform miracles on bent bumpers, but they're hard to find now. Literally a a dying art. Got a buddy with a H frame press? I've moved a lot of metal with this unit a buddy built 30 years ago. Set it up like this & watch all the crazy things the edges will do when you apply pressure. Work end to end slowly pushing a little at a time. You'll have to hammer on the back side, hopefully you have a heavy steel table. Knock down the highs, beat up the lows. The ends will stick out & might need heating to bend them around or maybe wedge cut & weld depending on what angle you need to fit & look good. Might cut & narrow in the middle. Use the biggest angle grinder you can find with minimum 6' disc, 36 or 50 grit. It's going to look worse before it looks better, just keep working it. If you have a local chrome shop they should be able to strip the chrome by soaking in hydrochloric acid, but there will still be nickel on it which takes special chemicals to strip & are expensive. Just grind all the plating off, use a good dust mask. Have fun & tell us how it turns out. I have a picture of my press, but it's not loading.........I'll try later

10-30-2009, 03:27 AM
Here it is

10-30-2009, 03:39 AM
We did the bumpers for this woody. The body shop did all the fab & welding. Narrowed & smoothed the bolt holes. They were not the best welders & we had a lot of pits & low spots to fill. Lots of copper plating & hours of hand blocking. Lots of money.

10-30-2009, 08:02 AM
Try Knox Custom Chrome. My friend and neighbor has worked there for twenty years, and his specialty is straightening bumpers.

Click here: Bumper Repair | Plating | Classic Car Repair | Custom Chrome | Antique Bumpers | Re-Chrome Bumpers | Knoxville, TN (

10-30-2009, 08:21 AM
Shoebox bumpers have a lot of curve and they are hell for strong. I think you'll kink it trying to take the curve out.

I'd be looking for another rear bumper, a straight one that fits your pan. '52-'54 Mercury might be a player. (

One of the methods used in the "old days" was to use the center of one bumper and the ends from another. Took a lot of time, but not nearly as much as straightening the curve out of a shoebox my humble opinion.

Just my $.02