In the process of doing the latest of many tire rotations, I cross-threaded one of the lug bolts on my FR wheel. I obtained a replacement lug bolt and nut from the Mitsubishi parts counter (part numbers MB911495 and MR455707) for about $2 and $4, respectively. Here's how to go about replacing the bolt:

(Sorry, no photos for this one as my camera is still packed away in a box somewhere.)

1. You'll be removing the brake rotor and calipers so make sure they're reasonably cool.

2. Jack up the corner of the car that you'll be working on; if it's a rear wheel don't forget to release the parking brake. Use chocks to prevent the car from rolling around.

3. The service manual specifies removal of the brake dust shield, but I found this to be unnecessary, as there's a big gap in the dust shield where the brake caliper sits; you can rotate the wheel until the bolt you want to replace lines up with that gap. This is easier to do by turning the tire since you can apply more torque to the axle than if you were just tugging on the wheel hub.

4. Undo lug nuts and remove the wheel/tire.

5. Front wheel only: turn the key to the "ON" position (just before ignition; do not start the car) to enable power steering, and turn the steering wheel so the front wheel you're working on points outwards as much as possible. This will make it much easier to reach things.

6. Remove the brake caliper assembly. It's held on by two bolts that are fairly easy to break loose. I found it fairly snug around the brake rotor so I put a couple lug nuts back on to hold the rotor in place so I could pull the brake caliper free. Use a piece of string, strong zip tie, etc. to suspend the caliper assembly, keeping it out of the way and making sure it doesn't just hang on the brake line.

7. Remove the brake rotor (disk); with the caliper removed it should just come off. If it's rusted on some PB Blaster penetrating catalyst and a bit of tugging should get it off.

8. Remove the lug bolt to be replaced. It's simply wedged in by a 1/4" section at the head of the bolt, and the way to get it out is simply to hammer it out. If you have some fancy press you can use that, but I didn't.

I made things easier by liberally applying PB Blaster (and giving it a while to seep in), and using cold spray (an upside-down compressed air duster can) to freeze the bolt to contract the metal a bit. I found that a few strong taps--like I would use on a decent-sized nail--with the hammer was enough to get the bolt out. Don't overdo it as you don't want to damage the hub. Give it a few strong taps, apply more PB and/or cold spray, and repeat until it comes loose. When it does, there's not enough room for you to pull it straight out, but a bit of wiggling should get it out.

9. Put the new bolt in place, and give it a few good taps with a hammer to get it lodged in a bit to keep it from coming loose. Because of the awkward angle of things, it may not go in straight; that should be okay as we proceed to the next step...

10. Put a thick washer (or two) on the bolt, and thread a large nut (I used a lug nut that I was willing to sacrifice) on to the bolt. Tighten the nut using an impact wrench or a breaker bar until the new bolt has been pulled straight and fully lodged in. Do it just enough to get the bolt fully in place--tightening beyond that could damage the bolt and land you back where you started. The washer prevents the nut from damaging the wheel hub. Remove nut and washers; if you used a lug nut, it's probably damaged from the extreme amount of torque you just applied, and should be discarded.

11. Put the brake rotor and caliper back in place. The two bolts for the caliper should be torqued to 80 lb-ft.

12. Put the wheel/tire back on; make sure the new lug bolt is straight and that the wheel goes back on effortlessly. Lug nuts should also be torqued to 80 lb-ft.

 

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