A Shock That Was Literally Shocking

Last week I revealed that I, your intrepid Hack Mechanic, owner of nearly 60 BMWs since 1982, will start the first new job I’ve had in 30 years, and will begin commuting to Bentley Publishers in Cambridge. Driving, apparently, a beat-up 2000 Suburban.

Fortunately, the automotive and meteorological powers-that-be spared me such indignity and professional embarrassment. When I started on Monday, it was 50 degrees out, so I drove to my new job in the Z3 with the top down, looking slightly ridiculous because the car now has snow tires on it, mounted on the gnarliest, rustiest steel rims you’ve ever seen. And then, well, I just got in the habit of taking the Z3—even when it was rainy and in the mid-30s.

Of course, with winter, an unsorted-out cooling system, and a thermostat that I know is sticking open, relying on the ragtop is a really bad idea. The very next repair I will do is to tear into the Z3’s plumbing.

But that comes after I’m done with the 325xiT wagon, which brings us to this week’s saga. Your Hack Mechanic, who has a chapter in his own damn book on how to make a car dependable, actually leads a schizophrenic wrenching life; I will follow my own advice and maintain my vintage cars—the ones in which I drive long distances to events—at a very high level, prophylactically replacing anything failure-prone or suspicious, and chasing down thunks and clunks lest they be due to something that may break the rest of the way on the road.

On the other hand, I will woefully under-maintain my purported daily drivers.

There’s context to this dichotomy, mostly involving years of having had a four-mile commute—which then collapsed to a zero-mile commute when I began working from home. I’m not defending my laxity; it’s a terrible way to own a BMW that feels so good when all the molecules are vibrating harmoniously together.

In my defense, when I bought the 325xiT wagon three years ago (which replaced the E39 five-speed sport wagon that was so high-maintenance that it nearly resulted in hobby desertion), I did the obligatory full-on cooling-system rehab, the CVV, and the VANOS seals, so I did, in fact, follow my own advice. And I’ve nipped around the edges at it here and there as necessary. But it hasn’t needed much. 

However, a few months ago, the back of the wagon became fairly noisy. Clearly something was off with the suspension, as it began to feel like an oxcart. A quick examination revealed that both rear springs had broken. This is not unusual; the design of the springs has them wound in tightly at the top and bottom, with the diameter of the metal itself becoming thinner to facilitate the tight winding.

I researched the problem and found that replacement springs by a number of manufacturers—including Kilen/Lesjofors and Suplex—feature metal of a constant diameter. These are less prone to breakage.

I filed this under “Yeah, yeah, I’ll get to it”—and of course did nothing. I was barely driving the car anyway, since it had been largely relegated to Ethan duty.

But last week, when I did need to use it, I was alarmed at how much worse the noises from the back had become. Clearly, something in addition to the spring was a-shimmyin’ and a-bangin’. I did a quick visual, plus grab-and-pull inspection of the rear shocks from beneath the car, and the right shock had an astonishing amount of play.

Okay, enough delay; let’s get this fixed.

One of the longest chapters in my book is called The Rhythm of Repair. In it, I talk about the different approaches to these sorts of projects. The best way to deal with any repair is to take the car down—meaning pull it off the road—assess what it needs, and then order the parts. However, that rhythm may be perfectly suited to an enthusiast car, but often it doesn’t work well for a daily-driver that needs to be up and running again on Monday morning. I wasn’t using the wagon, but Ethan was, so I wanted to slay the shock-and-spring dragon in one efficient session, if possible, by ordering everything I might reasonably need for the repair. On the other hand, I’m trying to be cost-conscious these days; I didn’t want to go overboard.

I ordered a set of Kilen springs from an eBay source for $147 shipped. At first, I thought about buying a set of front and rear H&R lowering springs instead; after all, if I might need to do the front struts soon, and if a whole set of springs was cost-effective, might as well, right? But the front springs on these cars don’t break with the regularity of the rears. And my front struts appeared to have life left in them.

I let the economics drive the choice. I thought, if I can find a set of front and rear H&Rs for $200, I’ll do it, but otherwise I’d just stick to the rears. I found a Black Friday special that was priced close, but not close enough. So: rear springs only.

For the shocks, I went cheap. Normally, I use Bilstein HDs in most of my cars, but the E46 wagon’s all-wheel-drive makes the steering feel kind of heavy and numb; it’s not a BMW I get any real yee-ha factor out of. I read some decent reviews of Sensen shocks on E46Fanatics.com, and at $18 per side from rockauto.com, I thought I’d give them a try.

Then the question was, how many ancillary shock components should I order? Replacing the upper shock mounts was a given, as these are known to go bad on E36/E46 cars. I wouldn’t know until I pulled the shocks, but a bad shock mount was the likely cause of all the play in the right shock. At twelve bucks a side for the Meyle heavy-duty mounts, it’s not something I’d re-use anyway. I do, however, generally re-use the rubber spring perches and the foam bump stops if I can. In this case, though, I could see that the bump stops were visibly degraded, and the fact that the springs had broken made me concerned that the perch rubber might be cut. So I bought it all. Adding $19 each for the protective damper tubes and foam bump stops—yes, more than the shocks—$7 each for the lower and upper perch rubber, before I knew it, I was  nearly another hundred bucks worth of odds and ends.

When the parts arrived, up went the E46 wagon on the mid-rise lift, and out came the shocks and springs. Pulling shocks out of the wagon is just as bad as it was in my Z3 M coupe; the fact that the rear wheel well is interior space on these cars means that you need to disassemble a Rubik’s Cube of interior trim pieces simply to get at the two 13-mm nuts holding the shock mounts to the top of the wheel arch. Fortunately, FCP Euro had an absolutely flawless E46 wagon shock installation YouTube video that removed all guesswork. Unfortunately, both the left and right seat-belt-guide covers shattered into several pieces when I tried pulling them off. So much for having ordered everything I might need for reassembly.

Finally I reached the point where I could pull back the sound deadening and expose the two 13-mm nuts holding the shock mounts. (Oh, all right; I hastened access by slicing the deadening material with a single-edge razor blade. You expected maybe the anal-retentive mechanic? He’s not here, dude.) I lowered the shock and examined it, and I was, uh, shocked. (For the record, an automotive writer can only use this awful joke once. I’m playing that Free Spin card right here. You’ll see why.)

The shock assembly had gone bad in three separate ways:

A. The shock was completely blown, having lost all of its hydraulic damping.

B. The collar holding the piston inside the cylinder had actually broken, allowing the shock piston to be pulled out of the cylinder and leaving everything just banging against everything else.

C. The upper mount had completely separated, leaving it free to join the cacophony from the shock beneath it.

No wonder it sounded like a dumpster was being emptied every time I drove over anything other than a glass-smooth surface.

First the new spring-perch rubber and springs went in. Since the old springs were broken, they came out easily, but getting the new springs in was tough. I consulted Bavarian Autosport’s video to confirm that they should be insertable without a spring compressor. I wanted to grab Ethan and asked him to stand on the lower control arm to force it down, but he wasn’t around, so I put a long ratchet extension in a strategic location on the lower arm, put a pipe over the end of the extension, tucked the end of the pipe under my arm, and leaned on it while I finagled the new spring into place.

Next I assembled the shocks. It was, I must admit, a joy to use all-new bumper foam and protective tubes. One thing I found from looking on realoem.com was that there is a shim—just a washer, really, part number 33 52 6 779 398—that slides onto the shock post above the bump stop. My old shocks were such a nasty, corroded mess that I wouldn’t have been able to identify the parts, much less reuse them. And this was the good shock.

The reassembly of the interior went quickly. I Superglued the fractured belt-cover pieces into submission. They’re fairly short money—about $20 each with a BMW CCA discount—but they need to be ordered. It’s the kind of thing I may revisit if I sell the car, but for now, I just wanted to get it back together.

One quick test-drive revealed a quiet car with a smooth ride. It felt good to have given my supposed daily-driver some love. I now can start tearing into the cooling system of the Z3.

But that presents a problem. Now I really will be driving the Suburban to work.—Rob Siegel