Removing a broken bumper bolt

[Glen C.]

I've got a broken bumper bolt on one of my rear bumpers. There's not enough of the bolt sticking out to get a grip on it. I've used easy outs on smaller bolts but this one is a pretty good size bolt. Are there any tricks I can use to get this out without damaging anything?

[Paul S.]

Re: Removing a broken bumper bolt

Assuming the bumper is off the car, assuming you are rechroming the bumper,,,,,, mig weld a smaller bolt onto the broken bolt. ( that is whats left of the broken bolt ). Then heat the sh*t out the nut that is part of the bumper. Or you can see if the rechromer will do it for you .but.... If you are not rechroming it ,, well good luck

[Edward J.]

Re: Removing a broken bumper bolt

Glen, Most of the bumper re-chromers will remove the broken bolt for you. Other wise it will require drilling and then re-tapping. Start with a 1/8 bit and start drilling and work your way up to about one size smaller that the bolt size, then re-tap hole.

[Gary B.]

Re: Removing a broken bumper bolt

Sounds like a perfect opportunity to try the CRC Freeze-Off stuff that was highly touted a few weeks ago, in conjunction with the use of an Easy-Out screw extractor.

Gary

[Greg H.]

Re: Removing a broken bumper bolt

I just went through this and used Edwards method above. Center punch the bolt, drill it out with increasing bit sizes. If you get close to the center you will be able to drill almost everything except the threads. Then tap it out... Carefully. A broken tap in a hole is a lot harder to get out than a broken bolt. The hardest part is holding the bumper in position for drilling. I tried both my drill press and a hand drill. I went up to a 3/8 drill then tapped with 7/16-14 and it's all cleaned out. I tried heating and using an easy out but no luck with that method. The side bolt on both rear bumpers broke.

[Bill M.]

Re: Removing a broken bumper bolt

The hardest part is holding the bumper in position for drilling.

I drilled and tapped some of the broken-off bolts in my '59 bumpers. I used a Black and Decker Workmate to hold the bumpers.

[John R.]

Re: Removing a broken bumper bolt

Sorry for the big pictures, but here is what I do. The hard part is getting a drill to go down the center, so I gave up on that. This is especially true when the part can't be mounted in a drill press. So I just drill a hole without being concerned with whether or not it's centered.



I usually start with a small bit, then go up to the hole shown above. Then I use cone shaped carbide bur and work around the top of the hole to enlarge and center it.

[Paul J.]

Re: Removing a broken bumper bolt

I just went through this and used Edwards method above. Center punch the bolt, drill it out with increasing bit sizes. If you get close to the center you will be able to drill almost everything except the threads. Then tap it out... Carefully. A broken tap in a hole is a lot harder to get out than a broken bolt. The hardest part is holding the bumper in position for drilling. I tried both my drill press and a hand drill. I went up to a 3/8 drill then tapped with 7/16-14 and it's all cleaned out. I tried heating and using an easy out but no luck with that method. The side bolt on both rear bumpers broke.

Glen, this is the method that I use, although I will sometimes try an easy out in between drilling. Notice that Greg is leaving the original threads and just cleaning them out with the tap, so he can use the correct sized (correct headmark) bolt.

Paul

[William F.]

Re: Removing a broken bumper bolt

I tried that freeze off stuff an rusted screws in BBQ grill and it didn't do squat; didn't even get cold let alone freezing. Mixed up half and half acetone and auto tranny fluid,squirted it on and was able to remove rounded off screws with straight jaw vice grips. Know this is different snce can't get hold on any of screw; just wanted to share my experience with the freeze off ; didn't work for me.

[Edward J.]

Re: Removing a broken bumper bolt

I tried that freeze off stuff an rusted screws in BBQ grill and it didn't do squat; didn't even get cold let alone freezing. Mixed up half and half acetone and auto tranny fluid,squirted it on and was able to remove rounded off screws with straight jaw vice grips. Know this is different snce can't get hold on any of screw; just wanted to share my experience with the freeze off ; didn't work for me.

Bill I have a Auto shop here in the Northeast and rust is always a problem, And through many years truly the best thing is heat, if its possible to grasp onto what is left of a broken bolt or screw. I currently have PB blaster and freeze off that I use every day, and the truth is there are no miracle elixirs. sometimes penetrating oil helps, and sometimes not.

[John R.]

Re: Removing a broken bumper bolt

Made the pictures smaller, but I wanted to post this because it has really worked well for me. The hard part is getting a drill to go down the center, so I gave up on that. This is especially true when the part can't be mounted in a drill press. So I just drill a hole without being concerned with whether or not it's centered.




I usually start with a small bit, then go up to the hole shown above. Then I use cone shaped carbide bur and work around the top of the hole to enlarge and center just the top of it.




Here is the result. You can see that only the close part or top of the hole is centered on the broken bolt, but as you look deeper its off. That's okay because the top of the hole will guide the next larger drill bit.

[John R.]

Re: Removing a broken bumper bolt

Then drill again. You can see the new hole it's pretty well centered. For some reason I can never get it this good unless the part is mounted in a drill press, which is hard sometimes.




From here you can use a larger bit and get very close to the threads. Sometimes they come out at this point, maybe due to the heat generated from the grinding and drilling. In this case, the next size drill bit I used took the remaining bit of the bolt out.




As suggested by others, when you get close enough to the threads you can just run a tap through the hole.



This works great when heat isn't practical, or when the bolt head breaks off, but heat is much faster!

[Terry M.]

Re: Removing a broken bumper bolt

Then drill again. You can see the new hole it's pretty well centered. For some reason I can never get it this good unless the part is mounted in a drill press, which is hard sometimes.




From here you can use a larger bit and get very close to the threads. Sometimes they come out at this point, maybe due to the heat generated from the grinding and drilling. In this case, the next size drill bit I used took the remaining bit of the bolt out.




As suggested by others, when you get close enough to the threads you can just run a tap through the hole.



This works great when heat isn't practical, or when the bolt head breaks off, but heat is much faster!

Nice work John and great pictures. Thanks for posting your solution.

[William F.]

Re: Removing a broken bumper bolt

Are you tapping new threads into the still present remaining periphery of the old frozen bolt rather than getting all of old bolt out first??? Please clarify.

[John R.]

Re: Removing a broken bumper bolt

Not sure if the question is for me, but in the example above I was able to get the old bolt out. Most of the time I can get so close to the threads that there isn't much of the original bolt left, and by messing with it, I can get it out. The tap just cleans things up. Sometimes there is so little material left that I can use a small chisel or ice pick or screwdriver and work the remaining metal out. Hard to explain, but easy to do. If there is a little lip, use a small chisel or something to hit it and push the threads towards the center of the hole. I wish I had pictures of that, but I don't. The worst that can happen if you really mess up is that you accidentally damage the threads. Been there done that, then it's time for a hell-coil or equivalent.