As those of you who follow me on Facebook know, Maire Anne’s 2008 Honda Fit Sport five-speed got totaled. I wound up replacing it with a 2013 Honda Fit Sport five-speed, a repaired salvage car with very low mileage that I bought for a great price. I only mention this non-BMW-related tidbit because in the interim between the untimely departure of Fit A and the arrival of Fit B, I gave Maire Anne my 2001 E46 325xi wagon to drive. This left me daily-driving the Z3, which is anything but hardship.
I’ve had the E46 wagon for about four years now. When I bought it, I did the requisite full-on cooling-system replacement, the CVV, and the VANOS seals. Other than replacing broken rear springs and bad rear shocks last fall, I haven’t had to do a lot to the car since the initial round of work. But with 170,000 miles on it, and a recent very harsh winter, it didn’t surprise me that the maintenance bill had come due.
Right about the time that Fit B arrived, Maire Anne reported that the E46 wagon was making a light grinding sound in the front. Perfect timing, I thought; now that my ’79 Euro 635CSi has brakes again, I can take it off the lift, put the wagon up, finally get the steel wheels and snows off—even though the snow has been gone for a while, the potholes have persisted, and I was perfectly happy leaving the used-up snows and beat-to-crap steel wheels on the wagon for another few weeks—and see what’s making the noise. I assumed it wasn’t brakes because I’d replaced the pads within recent memory.
When I got the car up, it was immediately clear what the problem was. The boots on both front CV joints were split open, leaving a family of gravel to move in and bring its in-laws. When I bought the car, everyone—and by “everyone,” I mean Mike Miller—told me not to let the boots split, or if they do, to catch them as soon as possible and replace them. Otherwise, I was told, the axles would need to be replaced, and there weren’t options other than expensive OEM parts and aftermarket Chinese-made junk.
So I needed to get the axles out. I’d never performed this repair before. The Bentley manual and two YouTube videos made it look easy: Use a chisel to bang out the safety detents from the big 36-mm nut securing the axle to the hub. Pull off the caliper and rotor. Undo the upper sway-bar end link to give the strut extra pivoting room. Remove the 18-mm bolt that holds the strut onto the steering knuckle, then pull the knuckle and hub off the end of the axle. Then pull the other end of the axle out of the differential. Then repeat on the other side of the car. Then install the new parts.
Ah, if life were only like that.
This is a car with 170,000 pedigreed New England miles on it. Nothing comes off without a fight. Well, that’s not quite true; the calipers came off easily enough. And I could see that the upper sway-bar links were rusty, so I used the torch and the Goodson’s Wax Stick on them, and the impact wrench zipped the nuts right off. But hokum smokum, other things had the New England Death Grip. The big 36-mm nuts sneered at my attempts to chisel out the notches into which the safety detents were hammered. I had to use a Dremel tool with a tungsten-carbide bit to rout the metal out, then heat, then wax, then the impact wrench. Slowly they came off.
But it was the 18-mm pinch bolt, the one holding the steering knuckle to the strut on the left side of the car, that became my nemesis. I used heat. I used Silikroil. I used wax. I whaled on it with the impact wrench. Figuring that it was a good-sized bolt that wouldn’t snap easily, I finally put a breaker bar on it, and a pipe on the end of the breaker bar.
Bad idea—really, really bad idea.
As I’ve written before, when a rusty, stuck nut succumbs to torque and finally starts to turn, there’s usually a loud crack as the corrosion binding the threads breaks free. This is why it’s sometimes called breaking the nut or cracking the nut. On the other hand, when you overwhelm a stuck nut or bolt with torque via a cheater bar, something is going to give; that may be what you want—threads turning inside threads—but it may also be what you don’t want, which is the bolt snapping. If it’s the latter, the socket will start to turn without the accompanying crack. That’s when you get a sick feeling in your gut, because you know your future is written.
And it involves a drill.
I’ve done this many times before. You center-punch the bolt so that you can position a drill bit as close to the center of the bolt as possible. Then you drill it out, using progressively larger bits until you’ve hollowed it out just shy of the threads. You pick the remaining metal out of the threads with a fine diamond-point chisel. If you’re lucky, the bolt remnant finally gives up the ghost and detaches from the threads, looking like a little Helicoil. Then you re-tap the threads, either cutting new ones or cleaning up the old ones.
Although I know the basics of how to do this, I got reams of advice on Facebook, some from pros who live and die by this stuff. Use a carbide bit, they said. They’re expensive, but it’ll cut through the bolt like butter. I’ve used cobalt bits before, but not carbide. But I was warned that carbide bits are brittle: Go slow and use lots of cutting oil. And if you put the carbide bit in a hand drill, it’s very easy to snap the bit by not drilling at a perfect right angle to the hole, so it’s better to remove the entire assembly that has the snapped bolt in it and set it up in a drill press so that you can drill perfectly square and not risk breaking the bit. The last thing you ever want to do when drilling out a bolt is to snap off a hardened bit, because then, as Bender says on Futurama, you are truly boned.
The offending fastener in the knuckle was a pinch bolt, meaning that it was squeezing a collar around the strut. The bolt went through the unthreaded half of the hole in the collar (which is actually where it snapped; it was rusted solidly into the half of the hole that had no threads). When it came out from there it went into the other side (the threaded side) of the hole. Each side was about an inch long. The back of the collar had a gap in it between the two sides.
I thought, this is perfect. I’ll cut the bolt at the gap. That serves two purposes. First, with the bolt cut, there will be nothing pinching the knuckle to the strut, so I’ll be able to pull the knuckle off and put it on the drill press and drill out the bolt nice and square without risking breaking any bits. And second, whenever you need to drill out a bolt, it’s best to make the bolt you need to drill through as short as possible by cutting off anything you can. So I positioned a Dremel tool with a cutting wheel at the slot and cut through the bolt.
With the bolt cut, I expected to be able to slide the knuckle off the bottom of the strut, just as I could on the right side of the car. But it wouldn’t budge. I heated it and beat on it, used lots of penetrating oil, and felt the knuckle loosen up, but still it wouldn’t come off the strut. Something was clearly holding it in place.
Finally I went and looked at the parts I’d removed on the right side, and realized what was going on. The bolt was not merely a pinch bolt securing a collar; the bolt passed through an indentation on the back side of the strut! In other words, the strut’s indentation was hung up on the bolt, even with the bolt cut in the middle. So the knuckle couldn’t be taken off the strut until the bolt was completely removed.
This was problematic in two ways. First, the axle—remember the axle? The whole point of this was to remove the axle—is held in place by the knuckle. The knuckle and hub have to be pulled off the outside end of the axle, then swung out of the way to allow the axle to be pulled out from the differential. And second, I wanted to bring the assembly inside the house to position it on the drill press to drill out the snapped bolt—but none of this can happen if the knuckle won’t come off the strut.
A Facebook friend said that, if necessary, the ball joint can be removed from the bottom of the knuckle, and that should give enough room to pull the axle out. I looked at it, but the nut holding the ball joint to the knuckle is almost flush with the underside of the outer CV joint. Forget using an impact wrench; there wasn’t even room to put a socket and a ratchet on it. It would have to be a box-end wrench. I tried, but it wouldn’t budge. I thought about putting a pipe on the end of the wrench, but been there, broke that.
Okay. So much for the “pull out the assembly and drill it out on a drill press” idea. It seemed that there was no choice but to drill out the broken bolt, in place, with a hand drill. I thought, “I’ll be careful. I’ll keep the drill square with the bolt. I’ll go slowly. I’ll use lots of cutting oil.” Yes, it was risky, but the removal of choice often necessitates the taking of risk.
I rotated the strut and knuckle assembly all the way to the left so the bolt face was oriented outward, and held the assembly in that position with zip-ties. I crouched on the garage floor, under the fender of the car, trying as hard as I possibly could to hold the drill square to the bolt face and maintain a constant angle.
The drilling went well. I wouldn’t say it cut like butter, but the ten bucks I paid for a single 1/8" carbide bit was money well spent.
However, despite taking extreme care, when I was almost all the way through drilling the bolt out, the carbide bit broke—with a good-sized piece lodged in the hole.
As Bender often says from the sidelines, “boned.”—Rob Siegel
Got a question for Rob Siegel, the Hack Mechanic? You can find him in the BMW CCA Forums here!
Rob's book Memoirs of a Hack Mechanic is available through Bentley Publishers, Amazon, and Bavarian Autosport—or you can get a personally inscribed copy through Rob's website: www.robsiegel.com.
