# How do I enlarge a bolt hole? Car strut bar question **URL:** \ **Category:** In My Humble Opinion\ **Created:** [April 11, 2018, 10:58pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252 "2018-04-11T22:58:09Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Jennshark](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@Jennshark](https://boards.straightdope.com/u/Jennshark)\ **Post date:** [April 11, 2018, 10:58pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/1 "2018-04-11T22:58:09Z")
The reinforcement tower plates for my strut bar are a tad less than 1/16" short of fitting one of the three bolts. I jacked the car up to see if there would be enough weight off the towers to shift bolts a bit (no go). Is there a tool I could use to enlarge the bolt hole just a teeny bit? Rat tail file? Dremel bit? Anteater snout? Pic of what I’m talking about: [https://goo.gl/images/Yx8hAf](https://goo.gl/images/Yx8hAf) ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [April 11, 2018, 11:11pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/2 "2018-04-11T23:11:31Z")
A [reamer](https://www.amazon.com/Woodstock-D4140-Repairmans-Taper-Reamer/dp/B005W17DFC) is what I would would use, but you could just pick the correct sized drill bit and drill it out. ETA: I got nothing from your photo. Not clear what the problem is. ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [April 11, 2018, 11:14pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/3 "2018-04-11T23:14:52Z")
_ **IF** _ I were going to do that, I’d use a [reamer](https://www.google.com/search?q=reamer&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj99dimrLPaAhXGUt8KHV3wAYAQ_AUICigB&biw=837&bih=429). But, are you sure you want to attempt it? You might negate a warranty or alter the balance just enough to cause havoc. IANAMechanic, just the Voice of Doom. ---
**Author:** ![Jennshark](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@Jennshark](https://boards.straightdope.com/u/Jennshark)\ **Post date:** [April 11, 2018, 11:19pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/4 "2018-04-11T23:19:55Z")
> [@beowulff](#): > > A [reamer](https://www.amazon.com/Woodstock-D4140-Repairmans-Taper-Reamer/dp/B005W17DFC) is what I would would use, but you could just pick the correct sized drill bit and drill it out. > > ETA: I got nothing from your photo. Not clear what the problem is. That’s one that’s installed; there are three bolt holes (there’s a hole under the arm you can’t see). ---
**Author:** ![Jennshark](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@Jennshark](https://boards.straightdope.com/u/Jennshark)\ **Post date:** [April 11, 2018, 11:25pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/5 "2018-04-11T23:25:06Z")
> [@burpo\_the\_wonder\_mutt](#): > > _ **IF** _ I were going to do that, I’d use a [reamer](https://www.google.com/search?q=reamer&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj99dimrLPaAhXGUt8KHV3wAYAQ_AUICigB&biw=837&bih=429). But, are you sure you want to attempt it? You might negate a warranty or alter the balance just enough to cause havoc. IANAMechanic, just the Voice of Doom. It’s for my 2004 BMW, so no warranty, etc. The strut bar for this model is strongly suggested, I’m going to track school on Sat and Sun. I’m going to try the reamer first. The bolt is sooooo close to matching the hole. Grrrr! ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [April 11, 2018, 11:37pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/6 "2018-04-11T23:37:40Z")
Hey, before you do anything, could you use a slightly smaller bolt/nut? ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [April 12, 2018, 12:17am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/7 "2018-04-12T00:17:36Z")
Did you just buy the kit? If so it may be defective so the solution would be to return it for a replacement. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [April 12, 2018, 12:39am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/8 "2018-04-12T00:39:46Z")
> [@burpo\_the\_wonder\_mutt](#): > > Hey, before you do anything, could you use a slightly smaller bolt/nut? Or, is it possible that the hole is sized for a metric/English bolt and you’re trying to use an English/metric one? ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [April 12, 2018, 1:55am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/9 "2018-04-12T01:55:07Z")
Before reaming out the holes, you might want to loosen everything and see if you can take a little bit of play out at each bolt/stud and make things fit. I could be off, but it looks like the bolt holding the two halves of the bracket is off-center to the hole in the top half of the bracket. It’s very likely that you already tried this; never mind if you did. ---
**Author:** ![PoppaSan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/poppasan/32/189_2.png) [@PoppaSan](https://boards.straightdope.com/u/PoppaSan)\ **Post date:** [April 12, 2018, 2:03am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/10 "2018-04-12T02:03:34Z")
A drill sized for the larger hole should be enough. I’d try the wiggle method with loose bolts first. Or get the correct add-on as you shouldn’t need to customize it to get it to fit if it is the proper one. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [April 12, 2018, 2:46am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/11 "2018-04-12T02:46:27Z")
> [@cornflakes](#): > > Before reaming out the holes, you might want to loosen everything and see if you can take a little bit of play out at each bolt/stud and make things fit. I could be off, but it looks like the bolt holding the two halves of the bracket is off-center to the hole in the top half of the bracket. > > It’s very likely that you already tried this; never mind if you did. This. Then use an alignment punch (just a tapered rod) to line things up for the last bolt. Amazon [link](https://www.amazon.com/TEKTON-66172-32-Inch-Alignment-Punch/dp/B00QV2JIO0). ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 12, 2018, 2:55am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/12 "2018-04-12T02:55:25Z")
Oh, a _bolt_ hole. nevermind. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [April 12, 2018, 5:55am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/13 "2018-04-12T05:55:07Z")
**Don’t do it!** You’ll be undermining the whole reason for the thing! Try this: Loosen all hardware, both shock towers. Use two jacks, and torque the car by jacking one side or the other till it fits. Then you’re straight! Get it all tizzite, and let her down. That’s what I would do, until I got drunk or frustrated, then I’d bust out the Dead Blow Hammer. ---
**Author:** ![Jennshark](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@Jennshark](https://boards.straightdope.com/u/Jennshark)\ **Post date:** [April 12, 2018, 11:52am UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/14 "2018-04-12T11:52:12Z")
> [@Gatopescado](#): > > **Don’t do it!** You’ll be undermining the whole reason for the thing! > > Try this: Loosen all hardware, both shock towers. Use two jacks, and torque the car by jacking one side or the other till it fits. Then you’re straight! Get it all tizzite, and let her down. > > That’s what I would do, until I got drunk or frustrated, then I’d bust out the Dead Blow Hammer. Hmmm, so I guess I’m going to my mechanic today 🕶 ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [April 12, 2018, 12:20pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/15 "2018-04-12T12:20:28Z")
With the method of “loosen everything, install the bar, then tighten everything up…” Assuming the bar kit is all of 1/16 too short, then the result of this operation would be to pull the top of each strut tower inward by 1/32 of an inch. Translating down to the bottom of the tower, to the wheel, wouldn’t this add a metric gob of positive camber to the system, hopefully evenly distributed between the front wheels? And if it does, can the camber be adjusted to negate that? For that alone I’d be more comfortable reaming the holes on the bar (if not returning it for one that is sized properly). Hard to believe an M3 wouldn’t have a strut bar–don’t they have, like, everything else from the performance wish list? ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [April 12, 2018, 12:23pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/16 "2018-04-12T12:23:58Z")
Aww…hey, um, looking at [the pictures](https://images.google.com/imgres?imgurl=https%3A%2F%2Fc1552172.ssl.cf0.rackcdn.com%2F558749_x800.jpg&imgrefurl=https%3A%2F%2Fwww.ecstuning.com%2Fb-ecs-parts%2Fecs-carbon-fiber-strut-bar-kit-silver%2Fecscf03b03-ace%2F&docid=b-LWFXUokyJe_M&tbnid=VUBN2YGQ_DtkMM%3A&vet=1&w=800&h=600&source=sh%2Fx%2Fim), is it possible the holes on the rod mounts aren’t all 130 degrees apart? Like, is it possible all 3 holes WILL line up if the base is spun & oriented in a particular way? ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [April 12, 2018, 1:53pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/17 "2018-04-12T13:53:38Z")
You need an alignment punch, as suggested earlier. Also try reversing the order that you insert the bolts. Insert the problem bolt first. Sometimes the others will go in. Sometimes you get a new problem bolt. It’s still always worth trying before using the alignment punch. ---
**Author:** ![Morgenstern](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Morgenstern](https://boards.straightdope.com/u/Morgenstern)\ **Post date:** [April 12, 2018, 2:19pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/18 "2018-04-12T14:19:20Z")
> [@Jennshark](#): > > Hmmm, so I guess I’m going to my mechanic today ������ If you’re intent on doing this, go to a processional driving school. A one or two day course, where the pro rides with you. Loose your bad habits (and you have many, everyone does) and just practice driving slow but correctly around a track. Then when you can recognize, analyze and understand things like weight transfer and polar moment, understeer, oversteer, etc. you’re ready for step 2. A day class with a professional driver will save you way more than the class costs. Start there BEFORE modifying your car. Then start with upgrading the brakes. You’ll find why out after 10 minutes on the track. Seriously dude, you’re about to enter an endless game of throwing money into a used car that will never be a track car, and if you get it close to a track car, you’ll hate it on the street. Save your money and buy a used Porsche 911. You’ll never be sorry. I’m speaking from experience. I had a 1987 Mustang interceptor (the one that looked like a cop car) that I dumped about 7,500 bucks in suspension/engine upgrades, and I did _all_ the work, except the welding. It hauled ass but it lost so much drivability for a daily driver it was a PITA to drive. ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [April 12, 2018, 2:23pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/19 "2018-04-12T14:23:37Z")
I concur with **Morgenstern** , having made many of the same mistakes, but starting closer to the edge of streetability already by having a Lotus. And definitely don’t drill out that hole. Unless you finish the job properly, you’ll create stress risers that could lead to cracking and failure of the part. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [April 12, 2018, 3:32pm UTC](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252/20 "2018-04-12T15:32:39Z")
> [@Morgenstern](#): > > Save your money and buy a used Porsche 911. You’ll never be sorry. Check the current prices on these. Then you’ll be sorry. 😃 [Next page](https://boards.straightdope.com/t/how-do-i-enlarge-a-bolt-hole-car-strut-bar-question/812252.md?page=2)