Dealing with Rounded Nuts

Broken bolts and rounded  nuts are probably the most common issues with working on a car over 20 years old. In fact, I’d say it’s one of the most common issues for any kind of mechanical work. Now that I’m finishing up the tear down on the donor for my all wheel drive Spyder project, I want to share some of the ways I’ve managed to remove rounded nuts. From low tech, high effort methods to specialty tools that cost more but make life easier, I’ll go over a number of ways to tackle the issue of a rounded nut. Later, I’ll follow up with an article and or video on broken bolts too, but for now, we’ll stick to nuts.

Each method has advantages and disadvantages. What you’ll find among the cheaper methods is that cost is often the only advantage.

Heat

Often times, I find that if a nut is stuck and starts to round, I can still get it off by adding a little heat and then coming back while there’s still something of an edge on the nut. Using a torch to heat up the bolt and letting it cool often helps break the nut loose due to the expansion and contraction creating and heating and cooling. Sometimes heating it up slowly with a torch and cooling it quickly with a lubricant can help as well. Just be careful not to start a fire.

  • Advantage:
    • Cheap
    • Easy
  • Disadvantages:
    • Only useful if you catch the issue soon enough or when combined with other methods below which is why I listed it first.
  • Links to buy:

Switch from a 12 point socket to a 6

I don’t actually have many 12 point sockets anymore. Once in a while, I’ll find a spot too tight to be able to turn enough for a 6 point, so I keep a few around. However, I find that 12 point sockets round nuts off more often than 6 points because they make less surface contact with 6 point nuts. In those cases, switching from a 12 point socket to a 6 point socket can let the socket grab onto part of the nut that isn’t rounded yet. Sometimes, I get lucky and that’s enough. Other times, it just rounds more.

  • Advantages: It’s easy
  • Disadvantages
    • It’s only cheap if you already have multiple socket sets
    • There’s only a slim chance it will work
  • Link to buy

Vice Grips

This is the first method I learned. Grab a good set of vice grips, clamp down on the rounded nut, and turn. What it has in simplicity and low cost, is often caught up to it by it’s overall ineffectiveness. Vice Grips take up a lot of space and often chew up the nut more to a point that they can no longer clamp hard enough to grip. I’ve had some limited success using vice grips over the years. About as often as it works, I end up with a nut that’s still at least halfway stuck and some pretty sore hands. I also found during the donor tear down that longer bolts had a tendancy to bend on me when using a vice grip. If you can’t replace the bolts, this can create more problems than it solves.

  • Advantages:
    • Cheap (to buy individually)
    • Easy
  • Disadvantage:
    • Requires a lot of space
    • Can make the problem worse
    • Constantly adding clamping force eventually leads to sore hands
    • Slipping on and off can get dangerous depending on the work space
  • Links to buy:

Screw Driver and a hammer

This method almost never works, but it did pull me out of a bind with a rounded exhaust manifold nut when I swapped to a forced performance manifold last year, so I wanted to mention it. You take a screw diver and put it on the edge of a nut and hit the end of the screw driver with a hammer. In a perfect world, the nut taps in the direction of the hammer swing. Most of the time, the screw driver just slips off the nut. Best case scenario when it slips, you get nowhere. Worst case, you whack or cut your hand or the screwdriver slips and cuts you. However, in the case of the manifold, I was able to wedge the screwdriver against the manifold runnier and hit in just the right spot to turn the bolt. It took me hours, but it came off. There wasn’t enough room for the other methods in this list beside the specialty sockets, which I didn’t have or know about at the time.

  • Advantages: cheap
  • Disadvantages:
    • Difficult
    • Slow
    • Ineffective
    • Slightly dangerous – You could slip with the hammer, or cut yourself when the screwdriver slips
  • Links to buy:

Cutoff wheel/hacksaw/dremel

The scorched earth approach. If you can’t get it off, destroy it. I almost never use this method. It’s only good if the bolt can also be removed afterward, because it almost always mangles or destroys the bolt too. I tend to use this method when the bolt and nut are cross threaded and both have to be replaced anyway.

  • Advantages: relatively easy
  • Disadvantages:
    • Expensive in the case of power tools
    • overly destructive
    • Can be somewhat dangerous either with debris or if you slip
  • Links to buy:

Nut Splitter

Like the saw or cutoff wheel, this method destroys the nut. However, it only destroys the nut, which is mangle beyond reuse anyway. I find this tool more practical than a saw or a cut off wheel for that reason. As you’ll see in the video below, the nut splitter is basically a clamp with a cutter that presses into the nut. Eventually, the cutter digs into the actual nut splitting it open, releiving tension between the nut and the bolt. Sometimes, it splits the nut enough for it to come out on it’s own, but often you end up using the splitter

  1. Advantages:
    1. Cheap
    2. Easy
    3. Effective
    4. Doesn’t destroy the bolt underneath.
    5. Much safer than a using cutoff wheel or a screwdriver and hammer
  2. Disadvantages:
    1. Limited usability – requires space and the nut cannot be receded into any surface or you won’t be able to get the clamp ring over it
  3. Links to buy:
    1. Nut Splitter Set

Sockets designed for rounded nuts

These are the latest tools I’ve added to my collection, and as soon as I got them, I knew I’d be writing this article and making the video below. Now that I’ve had a few opportunities to use them, I haven’t been disappointed at all. They slip right over the rounded nut like any other socket, but instead of a 12 or 6 point bolt pattern, they have a heliocentric shape that works like teeth to dig into the nut all the way around it, providing a uniform surface to grip. As the nut turns, it digs more and more in, tightening it’s grip. These tools aren’t cheap, but they work incredibly well. Unlike the nut splitter, they are the same size as a standard socket and can be used anywhere a regular socket can. Mine can be used directly with a ratchet, or you can slip a larger socket or wrench over the end, making them more usable in tight spaces.  They can also be used on either Metric or Standard (SAE) sockets, so you only need one full set.

  • Advantages:
    • Easy
    • Effective
    • Useful in tight work spaces
    • Works with most recessed nuts
    • Can be used with a breaker bar, impact wrench, or standard wrench/socket
    • Much safer than a using cutoff wheel or a screwdriver and hammer
  • Disadvantages:
    • Cost: A full set runs around $60, so it’s much more expensive than other methods. However, I ordered mine in two half set packs for $30 each, so you can spread the cost over time a little.
  • Links to buy:

The video below shows me using them to remove the rounded nut on the exhaust hanger bracket of our AWD donor, which was blocking access to the last few spot welds I needed to cut through to pull off the carrier bearing hangers. The tool I’m using in the video is a #7 socket, which is actually a size too small for the 14mm bolt I was removing. I didn’t realize at the time that I needed to order a second set to fill in the whole case, so I didn’t have the #8 socket. I got around this by tapping it on with a hammer, but you don’t actually have to do that with the correct sized socket. Once I got the right size socket, I was able to pull off the rest of the rounded nuts like I was using any other socket.

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