Redneck Car Bumper Straightening

[xroad]

Hi Folks,

My son's car got rear ended. The car is old, high mileage, still drive-able. I am unemployed and money is REALLY tight and I don't want to sink any money into this project. We'll drive this car to the ground and be done with it. So, I want to just pull the now v-shape bumper back to it's previous shape.

I've seen some hilarious YouTube redneck bumper, chain, tree set up. Tempting but it is not very controlled. Besides, my neighbor may not like a bumper flying through their window.

My original plan was to use a 3/4" threaded rod between the bumper and a 5 feet length of 6"x6" wood timber beam across the bumper. A slow controlled tightening of a nut will draw the bent bumper, plus the trunk lid, and whatever else attached to them, back to their previous locations.

Well, I ran into a problem. The bumper is a box section steel. I enlarged an existing hole to 3/4". I cannot get access to the back side of the hole to put a nut on the threaded rod.

I contemplate drilling another hole straight through the the other side of the box section bumper. Lacking a 3/4" drill bit and a large enough drill .....

Another great plan is to go to a welder and have him weld the nut to the bumper. Will the welded nut to the surface of the bumper be able to withstand the pull load?

Any suggestions would be appreciated.

-Bill

 

[metaleltr]

Yes a welded nut would withstand the pull. In the end you would still have a nut welded to the bumper. What kind of car is it? Can we see some pictures of this damage? What about a tree and a come along?

 

[John Mc]

A properly welded nut will take the strain. The threads should strip out before the weld breaks. Biggest problem is that the weld encircling the nut may shrink and deform the threads, or that the nut may be a leaded free machining steel averse to being welded.

E7018 stick rod or 70S-6 MIG wire has a tensile strength of 70,000psi. If the welder does his job, the filler wire will do the rest.

 

[xroad]

My son have the car (1999 Infinity I30) now. Moving back to his college dorm. I'll get some pictures, soon.

A come along sounds like a good possibility. Not sure if I can get an attachment of anything around the bumper. It is a crushed compressed mangled mess under there.

-Bill

 

[JJThrasher]

Picture would be helpful. If its an old steel bumper, chain and tree. Just drive slow and you can control it just fine.

 

[lilredex]

Here's my method...

I use a small hydraulic press made for a bottle jack (essentially a hoop), an 8 X 8" landscaping timber (longer than the bumper, and some 4 X 4's. Place the landscaping timber through the hoop, 4 X 4's outside the bend and apply hyd. pressure down on the bumper. You can supply controlled pressure to the top side, bottom or edge ...depends upon how you position the bumper.

Something like this, sorry no actual pictures.


green shot screen capture

 

[srmofo]

I Use A Racheting LoadBbinder In My Redneck Body Shop Collision Repairs. Wrap A Chain Around The Bent Parts And Pull It Out slowly

 

[Jere]

I am trying to what this bumper looks like and I can't. Can you just take the metal bumper off and put the plastic back on?

Can you take the bumper off and drill a hole in the opposite side and hammer the dent out with a long rod like some rebar?

 

[xroad]

I have to do it with the bumper still mounted to the car. Otherwise, the straightened bumper will not line up to the mounting points.

 

[koditten]

I've had good luck positioning the car between 2 trees. Anchor front to 1 tree and a comalong to the 2nd tree and the free end of the comalong to the bumper after the nut is wended to the bumper.

 

[Stuart in MN]

A picture of the rear bumper on 1999 Infiniti I30:

One with the bumper cover removed:

I think you're probably going to have to remove the bumper cover to have any luck in straightening it out.

 

[xroad]

The plastic bumper wrap, the bumper, and the sheet metal under it all ..... are like 3 sheets of paper crumpled together. If I peel off the plastic wrap, or the bumper, it will never be able to go back on. I started to take the plastic wrap off at the right side, behind the rear wheel .... once the screws and plastic studs are off ..... Boo-oine ! I cannot get the attachment points to line up anymore I think I'll stop here. If I pull everything together, all the attachment points will stay together, where ever they may end up.

The bent point on the bumper is behind the license plate slightly off to the left. That is where I will weld the nut to the bumper. That spot is not obstructed by the plastic wrap.

Have an appointment tomorrow with a friend to get the nut welded. I will post results.

If the threaded rod pull scheme don't work, I will post the video of the redneck technique. Somehow, that seems to be more fun than the threaded rod ......

 

[xroad]

Met up with my friend, who has a welder. We welder the big 3/4" nut onto the face of the bumper. Put the threaded rod in ..... humm, it is not straight out 90* to the bumper. Well, of course, the bumper is bent inward. The face of the bumper is facing off to one side.

So, I placed the 6x6" wood beam across the bumper, at an angle. I put some blocking one end of the beam to compensate for the angled beam. The tightening of the nut to draw the bumper out was difficult. Luckily, my friend has an adjustable wrench with a 2 feet handle. It was still exhausting. Then we figured out to put some grease on the thread ..... much better.

As the bumper is pulled out, we lessen the blocking at one end of the bumper as the face of the bumper is returning to face backward instead of off to one side. Found out the wood beam is not really pushing against the steel bumper. There is what looks like solid foam blocking between the plastic bumper wrap and the steel bumper. I was amazed that the solid foam did not crush that much.

We continued threading until it was almost totally pulled out to it's original position. Then it got even stiffer to turn. I think it is getting to a point all the sheet metals are stretched to a point where they all add up together to prevent the easier turning of the nut. Then .... I notice the face of the bumper by the nut is splitting. The weld is still holding. The metal is ripping. OK, time to stop.

Then my friend took out a hydraulic jack kit used for car repair. The hydraulic piston is separate from the pump. We did more pushing out of sheet metals from inside the trunk. Finally, tried to straighten the trunk lid and align the lock.

Aside being eaten alive by mosquitoes (nailed me over 60 times on my lower legs, was wearing shorts) the car turned out OK.

 

[bad_idea]

Sounds like a PITA. Glad it turned out decent. I began the thread thinking "get a chain a tree for crying out loud". At the end of the thread, I am thinking I will tuck this idea away for a later time. Hopefully I won't need to straighten a bumper, but the concept may prove handy for a different task.