When my friend Jeb showed me the $1,500+ repair estimate he’d gotten from his Mini dealership, I told him to hold off on the work. I’d fly to the rescue, arriving in Washington D.C. wearing my oil-covered cape and spandex tights made of recycled serpentine belts, and solve all of his troubles simply and on the cheap. Except that didn’t happen. We screwed up badly, and fixing that screwup was hell.
Earlier this week, I described how my visit to Washington D.C. had turned from what was supposed to be a fun wrenching session with an old college friend into a bit of a disaster after he and I cross-threaded one of his 2015 Mini Cooper S’ critical engine mount bolts. The text below, which I wrote with my spirit deep in the doldrums, shows the dire state we were in just a few days ago:
If [using a tap to clean the threads] doesn’t work, I’m not really sure what I’m going to do. I can try to find a compact, right-angle drill to make a new hole, and then tap new threads and use a larger bolt (or I can use a helicoil), but I think the area that I’m working with its just too tight.
So there’s going to be a lot of pressure not to screw up this thread restoration operation.
Thanks to my stupidly, one of the two bolts (50 percent of the fasteners!) holding the engine mount to the body of the car no longer had a good hole to thread into. This was a big deal, because an engine mount’s job is to literally make sure the engine stays attached to the vehicle.
The left side of the image below shows what the stripped hole—which is located in the car’s strut tower–looked like on the vehicle:
As I described earlier this week, my plan was to use a thread-chasing tool to clean up the hole we’d buggered up. Unfortunately, the tool—which I’d rented from AutoZone—wasn’t threading in without requiring lots of torque from my ratcheting wrench. I feared I’d snap the thread-chaser, and if that happened, we were truly doomed, because I had no idea how we’d have drilled that out given the space constraints.
Still, even though I didn’t snap the thread-restoration tool, I was concerned, because the mere fact that I had to put that much effort into turning the thing meant I was definitely not cleaning out the original threads, but actually creating a new threaded hole that was not coaxial to the factory one.
But, because I was unable to get to the back side of the stripped hole to make sure that my tap was cleaning the original threads instead of making new ones, I didn’t have much of a choice. So I snagged a tap from my Harbor Freight Tap and Die set, shoved it into the hole, and started cranking.
This tap was much sharper than the thread-chaser, so it was going in much more easily. But unfortunately, there was no room to use the included T-handle, meaning Jeb and I had to turn the tap with the most imprecise tool in any wrenching set: an adjustable wrench. And a cheap, made-in-China one, at that.
“We...couldn’t get a good grip on the weirdly square bit and didn’t have the range of motion to make decent progress with each push/pull,” Jeb later told me of the experience. “And the fact that we had to reset the wrench every 30 seconds was so inefficient and frustrating.”
“I’m getting angry just thinking about it again,” he continued. “I imagine it’s what trying to dig out of prison with a spoon is like.”
It really was hell. Luckily, to provide some much-needed inspiration, the man who changed my life forever 10 years when he taught me how to wrench was looking over my shoulder. A D.C. local, his name is Jake Thiewes, and while I’ll leave you to head to his website (he runs the gay, lesbian, bisexual, and transgender car site, Out Motorsports) to learn about what my first-ever wrenching session was like, here’s how he described what he saw earlier this week when he briefly stopped by the garage:
I spent the first part of my Monday evening standing in a garage in Northwest DC watching David spray PB Blaster on a tap while carefully (desperately) trying to fix the threads so Jeb could get to work with his only vehicle.
To tap new threads into a hole, you have to crank down a tap (rotate it clockwise), then back it off (rotate it counter clockwise), then crank it down, then back it off—over and over, while constantly lubricating it with light oil. To do this by grabbing onto the tiny square tap shank with a janky adjustable wrench that has lots of play in it was almost not worth our time. The wrench slipped often, and even when it didn’t, we could barely rotate it in the tight space between the motor and the shock tower/air conditioning lines.
We tried using a set of skinny vice grips, but those slipped off the tap immediately.
“Basically, we were just doing the job with the wrong tool, but there wasn’t a better tool we could use,” Jeb told me. And he was right, because it was really late at night and all the stores were closed, so picking up a ratcheting tap handle wasn’t an option. We had no choice but to use that crappy adjustable wrench; it was an agonizingly slow endeavor that took us over 2.5 hours, and left my forearm and wrist tingling.
Jeb and I eventually got the tap poking through the back side of the hole (we could see it through a tiny hole in the strut tower), though it was still really tight. We took the tap out, and threaded the old bolt in, and though it went in smoothly for half the depth of the threaded hole, the second half required us to put some force on the ratchet. Ultimately, though, we got the bolt to thread all the way through the back side of the hole in the strut tower without too much effort:
We then took the old bolt out, and had a look at the threads we had created. They were far from perfect, but they definitely look thread-like, so we ran with them:
With the new hole looking as good as it was going to, I lifted the AC lines out of the way, and Jeb coerced the new motor mount into place:
It looks quite nice, and unlike the old hydro mount (shown below), it’s not leaking.
With the new mount in, Jeb and I adjusted the engine height with the floor jack lifting up on the oil pan, moved the engine fore/aft a bit by hand, and pried the mount against the cylinder head so that we could align the three engine mount-to-engine bolts. We threaded those in and torqued them to spec.
We also torqued down the lower engine mount-to-body bolt pretty close to spec (we were using a u-joint tool since tool access was limited, so our torque wasn’t exact). As for the upper motor mount-to-body bolt whose threads we’d just re-tapped, I just tightened that by hand nice and snug. Even if we’d wanted to torque it to spec, there really was no way to get a torque wrench on it without a u-joint at a steep angle. Plus, I didn’t want to push it, so good and snug it was.
The threads seemed to take a decent amount of torque, which was a huge relief, and gave me confidence that our fix will hold the mount in place for the life of the vehicle.
Annoyingly, the aluminum engine mount came with some un-threaded holes for the bolts that hold the AC lines in place. Jeb and I hadn’t tapped these, because we never imagined an OEM part would require the user to tap new threads. Jeb and I ended up using the steel screws as taps, forcing them into the holes—this was annoying to do while the mount was in the vehicle, especially considering Jeb and I were done with tapping holes. Frankly, if neither of us ever had to do it again, we’d be happy.
With that done, Jeb and I attached the trim surrounding the motor mount, and bolted up the headlight. The light was actually incredibly easy to put back in; it’s held in place with just a few bolts and a single, intuitive plastic electrical connector. With that all fastened into place and the belly pan cover held back on with its 1 million small screws, we shut the hood gently, just in case we’d screwed up the light alignment (we hadn’t), and then hit the road:
The result of our wrenching was a Mini no longer stranded in Jeb’s in-laws’ garage, but instead sitting outside of his apartment. My buddy was thrilled, even though it was now 2 A.M., and he and I were both absolutely defeated:
I too, was happy, because I could tell Jeb had been a bit stressed out about taking over his in-laws’ garage, and I was beginning to worry I’d be responsible for family tension, which is never good.
Anyway, the car drove well, and Jeb ended up saving a bunch of money. Here’s the quote he’d gotten from his Mini dealer:
We ended up replacing the motor mount for under $400 including the tools we had to purchase. We (well, Jeb, really) also changed the spark plugs for only $92.29, a figure that includes new OEM-style NGK-brand plugs and the required special 12-point, 14mm, thin-wall socket.
Here’s a look at an old plug, in case you were curious:
Jeb installed a new cabin air filter himself for just over $24. It was a really quick task that required little more than removing a plastic panel from under the glovebox, though it did force Jeb to contort his substantial six-foot three-inch frame into the shape of a pretzel:
So Jeb saved about $75 on the cabin air filter, ~$175 on the spark plug job, and around $400 on the motor mount, bringing total savings to roughly $650. We didn’t have time to do the oil change or the brake fluid flush, but I suggested Jeb go to an independent shop for that instead of to the dealer, as those are trivial jobs.
As for time it took for us to do all this, the spark plugs only took 30 minutes, and the cabin air filter needed only 15. Those two were a breeze, and the motor mount would have been fairly simple, too, had it not been for the dreaded cross-thread. But alas, we made that error, and boy did we pay for it.
We spent 9 hours and 45 minutes on that awful, awful part, finishing the job and arriving back at Jeb’s place at 2 A.M. on Tuesday morning.
I’m honestly not sure it was worth it, and that’s coming from the cheapest of cheap-bastards ($650 is more than the value of most of my cars).