Tuesday, June 26, 2012

Jackass Award - GM's Theta-platform Front Hubs


2005 Chevrolet Equinox
This is a 2005 Chevy Equinox, one of a trio of first-generation Theta platform mid-size crossovers that General Motors sold in North America, the others being the Saturn Vue and Pontiac Torrent. The Spring Hill, Tennessee-made Vue came first, introduced as a 2002 model, with the Ingersoll, Ontario-made Equinox and Torrent following in 2004.

Seen below is the front hub assembly from the Equinox pictured above; a Torrent would be identical, a Vue similar. Incorporated into the hub is the front wheel bearing, which is a wear item, and a common failure part in many vehicles, though I can safely say that it's a particular weak spot in numerous GM vehicles. When the bearing portion of this part fails, it can result in excessive play, noise, or both. This one was noisy.

Front Hub Assembly - Before
So why is this worthy of a Jackass Award? Well, it's not for the failure rate, which, to be fair, may or may not be statistically significant - my sample area includes a higher than normal percentage of GM vehicles, after all. Not for using a hub design, which while more expensive to replace, is far, far easier to change than the press-fit wheel bearings frequently found in such applications.

No, the Jackass Award goes to the engineering team for this part, who obviously felt that it was not only a good idea to fit a steel hub into an aluminum steering knuckle (steel and aluminum don't play well together, especially in the presence of salt), but to do so with NASA-level tolerances that made this part a tight fit even before the swelling effects of corrosion became a factor. The bolts are what actually hold the hub in place, and there are several other vehicles where there is clearance or even cutouts around their hubs, so this one-step-short-of-press-fit design was unnecessary.

The end result is a hub that is remarkably reluctant to part ways with the knuckle. So reluctant, in fact, that it normally has to be beaten to a pulp to be removed. (The rear hubs on these vehicles don't exactly fall out either.)

Forget using a slide hammer here, as that will just pull the flange out of the bearing. The most effective extraction method, short of removing the knuckle/upright and putting it in a press (which no sane mechanic would want to do), is to baseball-style swing a Bloody Big Hammer at the flange until the hub and knuckle declare defeat, or the mechanic passes out. You can see what the hub looks like after 15 minutes of intermittent hammer swinging in the photo below.

I did mention the aluminum knuckle, right? Be careful not to hit that with the BBH - it's not really forgiving if you hit it in the wrong places. It's not unusual for the sheetmetal dust shield to suffer during this process, either. If it isn't rotten already. Don't worry, the dealer stocks it; you won't be the first to kill one.

Extracted Hub - After 15 minutes of on-and-off pounding, it's feeling a bit out of shape...

You'd think that a vehicle designed in North America and built in Canada would take corrosion into account. As you can see below, corrosion is definitely a factor here. (The machined face of the knuckle has already been cleaned in this photo.)

See the corrosion?
Oddly, the nearly identical component set in a similarly-sized Chevy Uplander minivan does not suffer from the same problem. Yes, it fails regularly, and it does use an aluminum knuckle with a steel bearing, but it normally comes apart with little fuss.

For designing a serviceable part in a manner that makes it far more difficult to actually service than it ever needed to be, while simultaneously failing to take into consideration the real-world environment that this product would face in its primary market, please accept a Jackass Award. A great example of Bonehead Engineering.

...and here's what the new unit looks like. I couldn't leave you hanging.

Friday, March 30, 2012

Photoshop Wizards At Work

I came across something today somewhat by accident, while reading the latest news on GM Inside News about the redesigned 2013 Chevrolet Traverse.

Included were a selection of GM's supplied-for-editorial-use photos - including these two images of what appear at first blush to be a pair of new Traverses. But, hey, hang on a second! If you look a bit closer, you'll discover that it isn't a pair of Traverses, it's the same damn one Photoshopped!

2013 Chevy Traverse - photo © General Motors

2013 Chevy Traverse - photo © General Motors

Don't believe me? Look at the license plate, or better yet, look at the way the reflections on the body match perfectly with each other (around the rear quarter panel it's really obvious). Not to mention the wheel spokes lining up.

GM (and others) have been digitally altering pictures like this for years - I have brochures for 1991 Chevy and GMC trucks and SUVs where it's plainly obvious the grilles and badges have been changed, particularly when you see the pictures side by side. In those days, you could normally spot the grafted-in parts.

These two photos illustrate perfectly just how seamless the software and techniques are now, since beyond the readily apparent colour change, this Traverse obviously couldn't have been photographed in at least one of these locations. Actually, my bet is that it wasn't shot at either of them, but I challenge you to find anything in these pictures that would give that away.

As a semi-pro photographer myself (I get paid for at least some of my pictures, so by definition I figure that I qualify for that rank), it disturbs me because I don't use any post-processing or digital manipulation unless clearly stated, normally not even so much as a general exposure or contrast correction. Frankly, I wouldn't have the talent or resources to pull off a composite image polished enough to pass for real anyway.

No, unless otherwise stated, any of the pictures that you see in this blog that belong to me are as they came out of the camera - for better or for worse - and those cars were where you see them. The same applies for those that appear in Wheels, as it is the Star's policy not to use altered pictures, the exception being "photo illustrations", which are clearly marked as such.

I'm not calling this evil, or even necessarily wrong, but I will say this: I try very hard to provide good quality photos, as I'm sure do many of my colleagues. How can we hope to compete with processed studio-shot images and idealistic backgrounds? For that matter, in this day and age, how can anyone believe anything they didn't see with their own eyes?

Wednesday, March 28, 2012

Shameless Self-promotion

2012 Chevrolet Sonic LT
You can find my Wheels review of Chevy's 2012 Sonic LT hatchback here.

Saturday, March 3, 2012

Shameless Self-promotion

2012 Chevy Orlando LTZ

You can find my Wheels review of Chevrolet's new Orlando here.

Saturday, February 18, 2012

Shameless Self-promotion

2012 Mazda5 (with aftermarket roof-top storage)
You can read my Wheels article on what four new 6-or more passenger vehicles you should check out while attending this year's 2012 Canadian International Auto Show in Toronto here. You'll also find my first appearance as a "talking head" for Wheels at that same link. Yikes!

Shameless Self-promotion

Fat guy on a ratchet - I help build the 100 Millionth Chevy Small Block engine

You can read my Wheels article about Chevrolet's milestone 100 Millionth Small Block V8 and its history here.

Shameless Self-promotion

2012 Nissan Leaf SL

You can read my Wheels review of Nissan's all-electric Leaf here.