Car Security Hack




I use a steering wheel lock in my car as a deterrent to thieves. So far (touch wood) it has done its job.

Last weekend, it broke. The key to unlock it would not turn and it took ten minutes of two engineers jiggling the key, the lock and the wheel before it was undone.

A piece of equipment like this absolutely has to be reliable, so I was going to have to replace it. Then I realised that since its primary function is as a visible deterrent, it didn't actually have to function as a lock, it just to look like one.

Step 1: Dismantling the Device

The device works by having an extensible bar which ratchets out between opposite rims of the steering wheel. This extensible bar is retained by a pin.

I could not find a way to remove the extensible bar pin as it seemed to have been installed at manufacture before the covering was applied to the far end of the device.

I broke the pin off by extending the bar to its limit very quickly to apply a transverse shock to the retaining pin. This took a few iterations but eventually the bar slid right out.

Then I went to remove the lock.

The inner barrel of the lock rotates, and there was a small pin visible on the outside of the lock housing. I assumed that this pin was what prevented the outer lock barrel rotating under torsion.

I marked the position of this pin with an ink dot on a piece of tape and then drilled it out with a 4mm (5/32") bit.

The pin was obviously extremely hard as the bit slipped off, but the steel around the pin was obviously very soft as the bit chewed down into it very easily.

Since the pin wasn't going to play, I drilled a hole in the steel either side of it and then used a punch to knock the pin sideways and out.

Step 2: Removing the Lock Barrel

After the pin was removed, the lock barrel was eased out.

The bolt which locked against the ratcheting bar was removed.

The inner and outer barrels were separated, which released the dozen lever and spring sets which formed the match for the key. They can be thrown away.

The lock barrels were reinserted into the steel housing.

The extending bar was slid back into the device.

Provided that the lock is put onto the steering wheel with the drilled holes hidden from view by the centre of the steering wheel, there is no external indication that the lock is not fully functional.

Step 3: What Failed, and What I'll Do Next Time

I tried a number of things which didn't make it to the final hack.

Unless the steering wheel is at the correct angle when the device is applied then the device will fall off, as there is nothing preventing the ratcheting bar from slipping back into the body of the device.

The first attempt tried to add some friction to the movement by jamming a piece of eraser into the housing where it would grip the ratchet. This sort of worked, but moved out of place whenever the ratcheting bar was moved.

The second attempt tried adding padding and friction to the ratcheting bar itself by various layers of tape (both duct and masking). This didn't work at all, as the difference between "no effect" and "jammed" was impossible to find.

The final attempt involved applying and expansion to the ratcheting bar by winding a spring and slipping it into the device before the bar. This was a bit of a Hail Mary and it didn't come. Dumb idea.

Knowing the internals of the device as I now do, a repeat of the hack would be much quicker to implement, more useful and more useable.

  1. Drill a single 4mm hole down beside the lock barrel retaining pin
  2. Punch the pin sideways
  3. Remove the lock
  4. Remove and discard the tumblers from the lock
  5. Reassemble, filling the drilled hole with epoxy or hot glue and painting the surface

This would retain the ratchet mechanism, but mean that anything (including a screwdriver) would open the lock.

You live and learn.



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    10 Discussions


    1 year ago

    I had a mechanic friend that cut off the end of a broomstick, painted it red, and just set it on the steering wheel if a vehicle had to be left on the lot at night. Never had a car stolen (or even broken into).

    Even with the new electronic anti-theft systems built into vehicles, we still "club" ours. I don't need to make them theft-PROOF... just a wee bit harder to steal than the next car over. Plus, in my mind, the club says "if they're overly cautious enough to use that thing, they're probably cautious enough to remove any valuables, so no sense breaking into it and attracting attention."

    4 replies
    Alex in NZallangee

    Reply 1 year ago

    I love the broomhandle idea :-) This one looks a lot more realistic (at least until you rock the car and it falls off).
    Regarding the actual purpose of all security measures, and how to bypass them, see this cartoon :-)
    Edit to add:- linking on this site can be problematic. Try ""


    Reply 1 year ago

    As a volunteer fire fighter, It was a well known method of though looking intimidating, the Club was NOT infallible. One thing to remember with steering wheels, is a thick padding, with a thin steel core, and not much holding the club after... Seen a few Police file photos, where the wheel was cut, and the club simply tossed into the back seat.

    Alex in NZgravityisweak

    Reply 1 year ago

    It worked when I posted it a couple of days ago. Just tried again on Explorer and Firefox and neither worked. The site is still there, so I'm going to blame the link rather than the destination. Thanks for the heads-up. is the site. That appears to have auto-embedded as a link, but pasting the xkcd thru 538 into a browser bar should get you there. Alternatively, google "xkcd" "security" and "wrench." It's a cartoon exploring the extent to which technical solutions can provide security in a world occupied by out-of-the-box thinkers.

    Thanks for the QA :-)


    1 year ago

    I saw in a documentary years ago on how thieves defeat the "club". It took 15 approx. seconds. The thief cut the steering wheel in one spot with a hacksaw and removed the club by pushing the cut steering wheel. Steering wheels typically are made of plastic with a small steel core.

    1 reply
    Alex in NZEurober

    Reply 1 year ago

    If you go to a scrap yard and examine a burned-out car, you'll get a good idea of what metal is actually involved in a steering wheel (and it isn't much).

    I'd guess that criminals (especially those who steal compact cars) tend to be lazy, so these devices (when they actually include a lock) suggest to the thief that they save themselves the trouble of sawing and go to steal another car.

    This project is really about taking a lock which can jam and trap you with an unusable car (since I assume you won't saw through your own steering wheel), and getting something which functions as a purely visual deterrent, not about correcting shortfalls in a commercial product.

    There are other anti-theft devices which cover the entire steering wheel to prevent cutting the rim. So to defeat those, you remove the wheel and drive with a pair of locking pliers on the steering column. Or drill out the device lock in situ. All security measures can be bypassed (see the XKCD cartoon which I linked in the comment below).


    1 year ago

    Two things came to mind reading over your posted project. First, I don't have to worry about any of my vehicles being stolen. Because nobody would want old vehicles that we own. Second, every lock has basically the same type setup with pins, springs and such. If you could remove the lock, it can always be repair to work like new again. Locks are there to make a typical person think twice about becoming a criminal. I real thief can get pass most type locks if they truly want to. JMHO

    Nice idea anyways.

    2 replies
    Alex in NZgm280

    Reply 1 year ago

    Forgot to say in response to "pins and springs so could fix it":- the failure of the lock to open when required was a real problem as I was trying to get somewhere. The failure was in the tiny tumblers, so trying to make new ones of those correctly would have been too slow, and I would still not have trusted the result.

    But thanks for your comment :-)

    Alex in NZgm280

    Reply 1 year ago

    It's often not the car as an item of value which gets stolen, rather it's the transport service. I used to park in a location which was on the route from the local courthouse to <area deleted on legal advice>. Misunderstood scamps (but society is to blame) would walk part-way home, then steal a car for the rest of the journey. A couple of hundred bucks for replacing a broken window isn't fun.

    Though that said, if I were parking in that place now, I would _definitely_ spend the money to buy a working lock.