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A Closer Look at Stabilizer Bars
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By Counterman
A constant velocity (CV) axle includes the axle shaft itself, along with the inner and outer CV joints as an assembly. The shaft itself is a rather mundane part, although there is more to them than meets the eye, but I’ll get to that in a little bit.
Perhaps the most interesting part about a CV axle is the joints, but it all seems more significant when we first look into their predecessor, the infamous u-joint. U-joints can handle a lot of torque, but they have a downside in the nature of their operating characteristics.
The basics are this: u-joints are located on the ends of a driveshaft, the most typical configuration a rear-wheel-drive vehicle, in which the joints are connected to a front and rear yoke. The front yoke attaches to the transmission and the rear yoke attaches to rear differential. As the engine moves from the effects of torque and as the suspension of a vehicle travels up and down, the angle of the driveshaft changes.
U-joints transfer the motion between the yoke(s) and driveshaft at different angles, allowing for driveline movement. When a yoke and the driveshaft are in perfect alignment, the velocity from one is transferred to the other at the same rate. However, when there is an angle between the two, the velocity of the driven member fluctuates continuously during rotation.
It can be hard to visualize, but the reason this happens is that as the angle of the u-joint changes, the two halves of the u-joint cross are forced to rotate on a different axis. The drive axis remains at a constant velocity, and both ends of the u-joint cross rotate in the same consistent
circular path.
The driven axis, however, rotates in a path which causes the distance of travel at the outer ends of the u-joint cross to increase or decrease in relation to the consistent points of the
drive axis.
This effect results in the continuous fluctuation of velocity between the input and output sides. While the input remains at a consistent speed, the output speeds up and slows down as the points of the driven axis continuously alter between a long and short path of travel.
So, why don’t we feel that on a vehicle with a traditional driveshaft? Because there are two u-joints and the fluctuation on each end balances out, effectively allowing the driveshaft to provide a consistent output speed to the rear differential. The angle of the two joints must be the same, however, and it doesn’t take much wear in one for the angles to differ, and subsequently cause a vibration.
U-joints are known for their propensity to cause vibration, and the other disadvantage they have is the greater the angle of the u-joint, the greater the fluctuation in velocity. Anything over 30 degrees and the fluctuation dramatically increases. Have you ever noticed how jittery an old four-wheel-drive truck feels in the front when the hubs are locked, and you turn a corner? Now you know why.
A Double-Cardan u-joint. It is basically two u-joints side-by side with a common link-yoke in between. This is one of the original concepts for a true constant velocity (CV) joint, and they are often referred to as this. The advantage they have is they offer smoother operation at greater angles, and they are common on four-wheel-drive trucks, and also a common upgrade for lifted trucks where the driveshaft angle is altered considerably.
The drawback to a Double-Cardan joint is they are bulky, and they can still suffer from limitations due to operating angle. True CV joints, as we know them today, have been around since the early 20th century, but the popularity of the front-wheel-drive (FWD) vehicle is what made them a household name.
Today’s CV joints are a radical departure from anything resembling a u-joint, and not only do CV joints transfer power without speed fluctuation, but they also can operate at angles up to and exceeding 50 degrees, depending on the joint. Since the drive wheels on a FWD vehicle also steer, the ability for this increased operating angle is what makes the CV joint so beneficial for FWD.
A FWD vehicle has two CV shafts, one on each side, and each shaft features an outboard and inboard joint. The outboard joints are considered fixed joints, meaning they don’t offer in and out movement. It’s their ability to operate at the increased angles for steering that’s important. The inboard joints are considered plunge joints, meaning they offer a wide range of inner and outer directional movement in order to take up for length differences as the suspension travels up and down.
You’ll see two types of CV joints. One is the Rzeppa design, which features steel balls trapped in a cage and riding on an inner and outer race. The tri-pod design is the second, which features three roller bearings that ride in a race or cage, sometimes referred to as a tulip assembly. Both types of joints can be found in either a fixed or plunging design for outboard or inboard use, but the Rzeppa design has proven more popular as an outboard joint. The Rzeppa works well as an inboard joint too, but the tri-pod design gets the nod for the most effective operation as a plunge joint.
link hidden, please login to viewTypical Rzeppa CV joint design. The CV shafts themselves can differ in length from side to side, and in early FWD development, torque steer, the vehicle pulling one direction or the other during acceleration, was sometimes a result of this difference. Different diameter shafts as well as hollow versus solid became part of the design aspects to combat this problem. Drivetrain mounting and torque control has also advanced considerably since the early days of FWD, and torque steer is rarely a problem.
Due to their overall advantages, CV shafts are now utilized front and rear, and it’s not uncommon to see driveshafts that feature CV joints instead of u-joints. U-joints aren’t forgotten, however, due to their ability to handle high torque and work well in abusive environments that may not be so friendly to the boot on a CV joint (such as the exposed location of a driveshaft under a truck).
link hidden, please login to viewTypical U-joint. CV joints are packed with a specially formulated grease, and a rubber boot is sealed to both the CV shaft and the joint, to keep the grease in place. When a boot is torn or begins to leak, the grease goes away, and dirt gets inside. CV joints typically need no service until this happens.
There was a time when the most common service for a bad boot was to remove the CV joint, take it apart, clean it, repack it and install a new boot. Generally, this was routine, however from time to time you could experience a nightmare. Much of the reason we replaced the boots and serviced the joints in this manner was due to the high cost of a replacement joint or a complete shaft. Even with the additional labor, it was far more cost effective to replace just the boot.
Over time, with advancements in manufacturing and the availability of supplies, the cost of complete CV shafts went down, and it simply made more sense to replace them as a complete unit, not to mention it makes things easier for technicians.
The most important part of selling a new CV shaft is making sure it’s the correct one. You should compare shaft length, the size of the CV joints, and if the vehicle is equipped with antilock brakes with a tone ring on the outer CV joint, be sure the replacement has this ring. Some early CV joints had the tone ring cast into them, but that design was quickly abandoned for a press-fit tone ring. If your customer doesn’t yet have the original shaft out, recommend they make these comparisons prior to installing the
new shaft.
Some CV shaft applications come with an ABS tone ring installed, regardless of whether or not the vehicle is equipped with ABS. If not, in most cases, the ring has no consequence, however in the rare situation where it rubs or contacts something, the rings can be removed easily.
The final, and perhaps most important, recommendation is to always torque the fastener that secures the outer CV joint in the wheel hub. If the factory procedure is not adhered to and the correct torque specification not used, damage can and will occur to the wheel bearing. CM
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By Counterman
Platform-sharing” and “badge engineering” are terms often used to describe the common industry practice of developing multiple vehicle models from a common design. The economy of a single design underpinning multiple vehicles allows manufacturers to streamline the development process, and to provide the buyer with options across their base, mid-line and luxury divisions. Much of this “twinning” occurs within a manufacturer’s “family” of brands, but cooperating with rival manufacturers already well-established in a market allows the manufacturer to produce vehicles outside their wheelhouse.
Ford Motor Co. has a long history of platform-sharing among its Ford, Lincoln and Mercury divisions, in addition to several collaborations with outside OEMs. As a global company for more than 100 years, Ford’s U.S. arm also has benefitted from the engineering of its European, Australian and Asian divisions.
Since its establishment in 1939, Mercury was positioned as Ford’s mid-range division, filling the price gap between the Fords and Lincolns. Mercury served this role until 2010, when the division was shuttered. The last Mercury rolled off the assembly line in January 2011. That final Grand Marquis had shared the Panther platform with the Ford Crown Victoria and the Lincoln Town Car – two models that also would be discontinued later that year. Prior to its closure, Mercury also had offered mid-range versions of the Mustang (Capri), Taurus (Sable), Escape (Mariner) and Explorer (Mountaineer).
Rebadging the Explorer has been a cottage industry for Ford. In addition to the Mountaineer, Lincoln offered the Aviator from 2003 to 2005, the MKT from 2010 to 2019 and the Aviator again beginning in 2020 (now based on the latest Explorer CD6 platform). After prior collaborations on Ford’s Courier and Ranger pickups, Mazda also was an early adopter of the first-generation Explorer platform. The Mazda Navajo was built alongside the Explorer in Louisville, Kentucky, from 1991 to 1994. Mazda and Ford later would co-develop the Tribute and Escape for 2001.
This kind of sharing hasn’t always been the case at Ford. At the end of World War II, Ford of Canada divided up its dealer networks, establishing standalone “Ford” or “Lincoln-Mercury” dealers throughout Canada. An unforeseen outcome of this separation was that the Lincoln-Mercury dealers did not have economy models or trucks. In 1947, these dealers received the first of the “M-series” trucks, which essentially were re-badged F-series Fords. A budget line of “Meteor” passenger cars was introduced in 1949. Ford dealers received the “Monarch” line of mid-priced vehicles to fill the gap in their own lineups. This arrangement continued until the 1960s, when tariffs on vehicle trade across our northern border were eliminated.
Mercury trucks were never sold in the United States, but in 1993, Mercury buyers were offered their first minivan, the Villager. This actually was a joint venture between Ford and Nissan, with Nissan-badged versions carrying the Quest nameplate. The Villager was assembled by Ford, but featured a 3-liter Nissan FWD drivetrain. It later would be replaced by the Windstar, which had no equivalent Mercury companion model at the time. The Windstar was renamed the Freestar for 2004, and regained a Mercury companion in the Monterey.
Lincoln, founded in 1917 and purchased by Ford in 1922, still represents Ford’s luxury division. Long known for large cars like the Continental and the Town Car, Lincoln in 2021 transitioned exclusively to crossover and SUV platforms. Lincoln had even tried its hand at pickup trucks, with the 2002 Blackwood, and the 2006-2008 Mark LT. Both were rebranded luxury versions of the F-150 crew cab platform.
In 2007, Lincoln adopted a new model-naming convention, playing on the heritage of the “Mark-series” nameplate used through 1998. The MKX and MKZ were the first of these, with the MKZ sedan being the Lincoln version of the Ford Fusion and Mercury Milan, and the MKX being a Ford Edge-based crossover (“X”-over). Originally intended to be spoken as “Mark-X” and “Mark-Z,” both vehicles were produced on the same CD3 platform originally developed for the Mazda 6. The MKS sedan (based on the Taurus) and the full-size Explorer-based MKT followed in 2009 and 2010, respectively.
In 2015, the MKC compact crossover was introduced, built on the Escape platform. Lincoln has since dropped the “MK” designations in favor of proper names for its crossover and SUV lineup, which is a relief to anyone who has misheard or misspoken these similar-sounding model names while looking up parts!
Ford-Lincoln-Mercury (FLM) dealerships once were a common sight here, with all three divisions available in one location. But, after a decade without Mercury, Ford-Lincoln dealers are fracturing yet again. In 2019, Lincoln began an initiative to develop standalone Lincoln dealerships to market more exclusively to the upscale clientele of the luxury-car market. Targeting 30 U.S. metro areas, Lincoln-only showrooms have already opened in half of the roughly 150 planned locations. Sales are up at these dealerships, but they still don’t have pickup trucks!
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By Counterman
rack: noun
1. The linear component of a rack and pinion gearset.
2. The short name given to a rack and pinion steering assembly for an automobile.
This is one of those times when the same word is used over and over to describe two things that are related but different. When I first learned about rack-and-pinion steering, it was anything but new. Nonetheless, in my world, I was used to traditional. I was among the guilty who shunned things that in no way could ever be better than a carburetor, points, condenser and crank windows.
When it came to steering, if it didn’t have a steering box, pitman arm, idler arm and a center link, it probably wasn’t a real car.
You laugh, but now, so do I. Automotive technology always has changed for the better, and rack-and-pinion steering just made sense. It was simple, less expensive, lighter-weight and simple to maintain. The term “rack and pinion” describes a type of gearset that transfers rotational motion into linear motion. In the case of an automotive application, the rack-and-pinion gearset is housed in a unit that we simply refer to as the steering rack, or rack for short.
So, a steering rack transfers the rotational motion of the steering wheel into the linear motion required to move the tie rods left or right for steering. They initially became commonplace on small economy cars and were additionally well-suited for front-wheel-drive applications due to the limited space they require. Now, almost every new car, SUV and light truck on the market has rack-and-pinion steering.
A simple design and low maintenance are benefits of a steering rack, but that doesn’t mean they haven’t caused a headache or two over the years – and there are many questions you’ll still field about these systems. While they’re too difficult to describe, the service aspect is where you’ll get most of the questions, and this is where your customers will benefit from your knowledge. After all, as a counter professional, you’re in the business of answering questions.
Many early steering racks on small cars were simple manual racks with no hydraulic assist. These were my favorite. They rarely developed any problems and, in many cases, would last the life of the vehicle. Then, cars got heavier, people got softer and hydraulic power steering for the most part became standard. Today, electric power steering is taking over, and in many ways with the lack of a hydraulic pump, hoses, lines and leaks, it has brought back the simplicity of the original manual rack.
Although many aspects are the same regardless of the type of assist, in this article I’m going to focus on hydraulic power-steering racks. They’re still going to be around for some time, and service considerations are where you’ll get most of your questions. Making sure the job is done right is important for not only safety and efficiency, but it also helps prevent unnecessary warranty hassles.
First and foremost is power-steering fluid. It’s commonly overlooked and neglected. The valving and seals inside a hydraulic power-steering rack rely on clean fluid for proper operation, and just like any other fluid service, ignoring this can shorten the life of the steering rack. When replacing a rack, fluid should be drained and flushed as best as possible, and it’s a good idea – as well as a good upsell – to install an inline filter. Most of these types of filters work with a magnetic mesh that’s especially beneficial to trap small metal particles.
One of the most common problems to arise is a torn rack boot. These rubber bellows-style boots expand and collapse every time you turn the wheels, and it’s just unavoidable that they eventually wear out. There are two immediate problems with this. One, the inner tie-rod ends will collect dirt in the grease that lubricates them, and two, dirt and debris will be drawn into the rack seals every time you turn, eventually causing damage and leaks.
link hidden, please login to view Torn boots should be replaced as soon as possible when they’re discovered, and the vast majority of them require the removal of the outer tie-rod end. An alignment is required afterward – no ifs, ands or buts.
Worn inner tie rods are another common problem, and while “technically” not part of the steering rack, service procedures can affect the integrity of the rack. Many new racks come with new inner tie rods and boots pre-installed to prevent damage from incorrect installation, so the boots keep everything sealed up from the start.
Most of the time, replacing the inner tie rods requires a special tool, kind of like a deep socket on steroids – deep enough to reach over the length of the tie rod and access the inner end where it bolts to the rack. On the end of the tool is a half-inch square drive. The factor to be aware of is that by-the-book service procedures call for holding the rack (the actual internal component) in a soft jaw vise when removing or installing the inner tie rod, so you don’t twist it and risk damaging the pinion gear.
The problem is in practice, this is rarely done because there’s no way to do it with the entire assembly installed in the car. There’s simply no access to get any type of holding fixture onto the actual rack. For fun, I looked up the top videos on the internet for installing inner tie-rod ends, and none of them mention holding the rack. Perhaps because they don’t want you to know they didn’t do it, or they don’t know the solution because there really isn’t a good one – at least not one I’ve learned of yet.
You might be able to get locking pliers clamped onto the rack to hold it, but that would gouge the machine-finished surfaces and tear up the rack seal, so that’s out. So, how serious is the problem? Most inner tie rods don’t require very high torque, and many of them use a type of thread locker, a locking nut or a type of retainer to prevent loosening. The bottom line is, if you use hand tools to loosen and tighten the inner tie rod, and slowly torque it to the correct specification during installation, the pressure against the pinion is going to be minimal, and damage is unlikely.
Whatever you do, use hand tools. Do not use an impact wrench on the end of the inner tie-rod tool. This will transfer a series of blows directly into the pinion and the valve assembly inside the unit, and you could be asking for trouble.
As mentioned before, any time the rack or a tie-rod end is replaced, an alignment will need to be performed. But, just as important is any time the rack is being replaced, the steering shaft will be disconnected. Always make sure the steering wheel isn’t allowed to spin free, or the airbag clock spring will be damaged. Also, make sure the rack is in its centered position before initially disconnecting the steering shaft and before reinstalling it.
Quite possibly the most useful tip for new steering-rack installation involves cleaning the splined steering-shaft connection. It’s a precision fit. In other words, both sets of splines need to be perfectly clean. If they are, they’ll slide right together. If not, you’ll fight it forever. Many new (or remanufactured) racks are painted, and it’s not uncommon for overspray to get on the splines. This may seem inconsequential, but the thickness of the paint is enough to cause a nightmare.
There are many opportunities for upsells with steering racks and related services. Outer tie-rod ends are often replaced one at a time and, in many cases, this is all that’s needed. Still, it’s a good reminder to check the rack boots and other ends closely. Since an alignment will be required, it’ll save money in the long run to take care of any pending issues now.
If you’re replacing an inner tie rod, you’ll already have the outer and the boot off. It’s often much easier to replace them too. Brake/parts cleaner is a good solvent for cleaning out reservoirs and lines, but make sure they’re allowed to completely dry before sealing the system up. I like to use clean power-steering fluid as a final flush to make sure any trace of solvent is gone, so selling a little extra is a good idea.
Tool upsells can include the inner tie-rod tool, an outer tie-rod separator and a grease gun if grease fittings are included on any of the front-end components.
The crowning touch is service information for torque specifications and bleeding procedures. Everyone should have a manual, and you’ve got them on the shelf, right? This is the perfect job to recommend one.
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By Counterman
Metallurgy is the study of the physical and chemical properties of metal, and when comparing different metals, the question becomes whether one wants to pursue a complicated degree in science, or whether you’re OK with accepting the basic facts around it.
The science is cool stuff, but I’ll leave it for my next life. I’m OK with the basic facts, and it’s the knowledge of these facts that makes it much easier to understand the basic types of crankshafts, or “cranks” for short.
In this industry, whether you’re interested in performance or not, you can’t escape the conversation of it, and one of the first things that always comes up is the term “forged” crank. Everyone knows the term and knows they’re better, but why?
Back up to the era of muscle cars and the exploding popularity of hot-rodding and aftermarket performance parts. As the horsepower wars accelerated throughout the ‘60s, the high-performance variants of any engine had one thing in common: a forged crank.
When you think about what a crank does, it harnesses all the power created by combustion and transfers that power to the transmission. Visualize what they go through: The power of combustion transfers through the piston and rod and into the rod journal to drive the crank into rotation. Meanwhile, the next cylinder in the firing order is compressing an air/fuel mixture in preparation for firing and driving the piston downward. Add to this engine speed and the momentum of pistons and rods that are holding on for dear life – not to mention the shock to the system by dumping a clutch to launch – and you can paint an easy picture of the immense forces pulling and twisting on the crank, just waiting to expose a weakness.
The bottom line is the crankshaft needs to handle the abuse it gets, and everything from compression to rpm to how hard the vehicle will be driven are factors that must be considered. This is why during the heyday of muscle cars the top performers had forged cranks. It was more than just handling the horsepower; it was the fact that these cars were going to be run hard over and over again, and many of them on the track.
Iron vs. Steel
Iron is a natural element that comes from the earth. Steel is a man-made alloy that’s a result of mixing iron with carbon, and it’s ultimately a stronger material. Those are some of the basic facts I was talking about. Metallurgy 101. Done.
Casting
For years, the traditional or “standard” crank was made of cast iron by pouring molten metal into a mold. When the casting is removed, it’s very close to the finished dimensions and comparatively requires minimal finishing. The entire process has a considerably lower cost than any other. As a result, this has been the standard crank of choice for automakers for many years.
Now, cast iron certainly is no wimpy material – think frying pan – and cast-iron cranks are very functional, but they have a limit to the amount of power they can handle in an engine. Generally, they’ll perform well up to the range of 450 to 500 horsepower, but when you reach that level (especially when driven hard on a regular basis), it’s time to move to something more durable, and the forged crank enters the picture.
Forging
A forged crank starts as a large cylinder of steel, heated to the molten state. It’s then pressed and/or twisted into shape by large dies. The ultimate difference between a casting and a forging is the resulting grain structure of the metal. A casting produces a sand-like grain versus the uniform flowing-grain structure of a forging. This grain structure is the reason for the difference between the strength of a cast and forged crank.
Billet
A billet crank starts as a large cylinder of steel, which then is machined into a crankshaft. Since a billet crank isn’t pressed or twisted in a forging process, the resulting grain structure runs parallel throughout the entire piece. Is a billet crank stronger than forged? Arguments go both ways, but billet seems to get the nod most of the time.
Just a Little More Metal
Cast cranks can be made of iron, nodular iron or steel. Add a small amount of carbon to iron and you have nodular iron. Steel has the greatest amount of carbon, and by definition is an alloy. There are thousands of different types of steels. Forged cranks, as well as billet, are made of multiple grades of these steel alloys. The difference in all – from least expensive to most – is tensile strength. Tensile strength is another term related to metallurgy. It refers to the amount of force that a metal will withstand before it begins to stretch.
So, the two underlying factors in crank strength are material and manufacturing process. Ultimately, you can go from bottom to top, aligning tensile strength, price and how much horsepower a crank will handle. Less costs less, more costs more. It’s that simple!
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By Counterman
If you were to ask a Subaru owner, they may tell you that their world is flat. No, I don’t mean that they think the earth is flat. It’s a clever euphemism for the distinctive engine design used by Subaru: the flat, or boxer engine. The boxer engine is to Subaru what the V-8 is to muscle cars. You may have seen a T-shirt or decal somewhere with the icon below. It’s an illustration of a crankshaft and pistons from a boxer engine.
But there’s so much more to this automaker than its distinctive engine types. Let’s take a closer look at what makes Subaru so special, and what makes it tick as a brand. After that, we’ll look at a few common repairs so you’re prepared to help your customers find the part they need to get their vehicle back on the road again.
Flat Engines vs. Boxer Engines
Subaru engines are often misunderstood. People commonly refer to them as flat engines, but this isn’t the case. There’s one major difference in the construction of these two types of engines.
Both flat engines and boxer engines will have cylinders on either side of a central crankshaft, but the crankshafts are different in each engine type. A flat-engine crankshaft will mount two opposing connecting rods onto a shared crank pin (Figure 1), whereas a boxer engine will mount each connecting rod onto its own separate crank pin (Figure 2).
This subtle difference in construction affects the way the pistons move inside the cylinders. In a flat engine, one piston will move inward while the opposing piston moves outward. In a boxer engine, each opposed pair of pistons will move inward and outward at the same time.
Boxer engines produce significantly lower vibrations when compared to other engine configurations. Since each opposing piston is moving in and out at the same rate and speed, the opposing forces are canceled out. This means that they don’t require counterbalance shafts to smooth out their operation, and the internal components don’t suffer from the same sort of wear and tear caused by vibrations.
Boxer Engines
Boxer engines offer a number of advantages over other engine styles. (It wouldn’t make sense for Subaru to keep installing these engines into their vehicles if that wasn’t the case.) First and foremost, the boxer engine is incredibly compact. It’s effectively a V-4, with two cylinders on each side of the central crankshaft. This means that the overall length of the engine block is only a little bit over the length of two cylinders.
Boxers also are compact vertically, so they can be mounted lower in the engine bay. This pays dividends when you consider the center of gravity in the vehicle. The engine tends to be the heaviest component in the front of the vehicle. If the engine can be mounted lower in the vehicle, it lowers the center of gravity. This leads to better driving dynamics, better stability in corners and reduced understeer (Figure 3).
Understeer is a phenomenon that causes the vehicle to not turn as sharply as intended. Have you ever put a 24-pack of drinks in the front of a shopping cart, then tried to turn the cart at the end of the aisle? That’s understeer.
As I said earlier, boxer engines produce less vibration than other engine styles, and don’t require any additional counterbalancing to operate smoothly. And last but not least, they produce a truly distinctive exhaust note. Seriously, it’s music to the ears. Well, that may be the car enthusiast in me speaking.
Now, all of these advantages aside, there are a few drawbacks.
The engine assembly is rather complex, both during manufacturing and when rebuilding later on down the road. In an inline or V-style engine, you can place the crankshaft into the main bearings, torque the main bearings, then install and torque the connecting rods onto the crank pins. All of this can be done from underneath the engine with relative ease.
Boxer engines use a crankcase that’s split into two pieces. You can’t access the crankshaft to torque down the connecting-rod caps once the crankcase has been put together. So, the connecting rods must be installed and torqued down onto the crank pins with the crankshaft supported outside of the engine. Then the entire rotating assembly is installed into the crankcase. Or is it?
Nope! The pistons need to be installed onto the connecting rods AFTER the two halves of the crankcase have been bolted together. There are special access holes in the front and back sides of the block that allow you to slide the wrist pins into place (Figure 4). There are a few common issues in boxer engines once they start to age, but we’ll come back to those later on.
Symmetrical All-Wheel Drive
If there’s one other thing that Subaru is known for, it’s the all-wheel-drive system. Known as Symmetrical All-Wheel Drive (SAWD), Subaru has been perfecting the art of driving all four wheels for decades. SAWD was first introduced in 1972 as an optional part-time four-wheel-drive system on the Leone wagon. This early four-wheel-drive system was all-mechanical, and has evolved into the more electronic SAWD system that we know today (Figure 5).
Modern SAWD systems work in conjunction with the vehicle dynamic control, antilock brakes and traction control for optimum handling performance and grip. Subaru has earned a reputation as one of the best vehicles to drive in snowy conditions, or offroad adventuring thanks to the superior grip and stability offered by SAWD. I’m willing to bet that you’ve seen a Subaru Outback with a suspension lift, big offroad tires and a roof rack out on the road. In fact, it’s not uncommon to see Outbacks, Foresters and Crosstreks set up for offroad adventuring out on the road today.
Safety
Subaru’s commitment to safety has led to years of industry-leading advancements in both passive and active systems. A precision-engineered, strong vehicle frame will provide maximum protection for passengers in the event of a collision. Subaru’s advanced airbag systems can deploy up to eight airbags, protecting the passengers from forces in all directions (Figure 6).
In other vehicles, the engine and/or transmission may be pushed inside the passenger compartment during a front-end collision. But, thanks to the compact size and placement of the boxer engine, the drivetrain is pushed downward and away from the passengers in a Subaru (Figure 7).
It’s clear that Subaru’s commitment to safety has paid off. A cursory glance at the IIHS website shows strong ratings for all of its current models. In fact, Subaru earned Top Safety Pick or Top Safety Pick+ ratings on the following 2022 model-year vehicles:
• BRZ (Top Safety Pick+)
• Crosstrek (Top Safety Pick)
• Crosstrek Hybrid (Top Safety Pick+)
• Impreza (Top Safety Pick)
• Legacy (Top Safety Pick+)
• Outback (Top Safety Pick+)
• Forester (Top Safety Pick+)
• Ascent (Top Safety Pick+)
The only model missing from this list is the WRX. It appears that the 2022 WRX hasn’t been crash-tested at the time of this writing. Based on Subaru’s track record, I wouldn’t be surprised to see the 2022 WRX also earn its place on this list in the near future. I went back 10 years on the IIHS website and saw consistent top safety-pick ratings for the brand throughout the past decade.
In addition to these strong crash-test ratings, Subaru has pioneered several advanced driver-assistance systems (ADAS) to help drivers avoid collisions whenever possible. The EyeSight system uses a series of cameras to scan the road ahead of you (Figure 8), and apply the brakes if needed to avoid or minimize a collision. Subaru’s DriverFocus system looks for signs of a distracted or drowsy driver, much like an attentive front-seat passenger might do. And of course, Subaru offers other ADAS systems for added safety and convenience including blind-spot detection, rear cross-traffic alert and reverse automatic braking just to name a few.
Motorsport
I’d be remiss if I didn’t mention Subaru’s strong racing heritage. Subaru has proven itself in the racing world by pitting its engineering and manufacturing skills against the competition. And of course, Subaru’s success on the racetrack has led to advancements in its road cars.
If you want to get a closer look into the Subaru racing world, I highly recommend searching for a video series called “Launch Control.” This show follows the Subaru Racing Team USA (SRTUSA) season after season. You’ll see driver profiles and background, vehicle development and the challenges that come along with running a race team.
Common Issues
As with all things that are mass-produced, there are some common failures you should be on the lookout for. If a customer walks into your store with a question about their Subaru, you may be able to help them find exactly what they need to perform the correct repair and keep their vehicle on the road for as long as possible.
Due to the design of the boxer engine, the cylinders are mounted horizontally on either side of the crankcase. This orientation means that any sediment, debris or contaminants that might be present in the cooling system will settle down inside the coolant jackets instead of elsewhere in the system. The same thing will happen with the oiling system. Over time, this can cause the head gaskets to leak, leading to oil and/or coolant consumption, leaks and abnormal smoke from the tailpipe.
This is an issue that has garnered a lot of attention on social media and other channels, but it’s not a guaranteed problem with every single Subaru engine. Routine maintenance such as oil changes and coolant flushes can help to extend the life of the engine and all of its components. There are two types of head gaskets that will be found inside the boxer engine: composite and multi-layer steel (MLS). If the customer removed a composite gasket from their engine, an MLS replacement gasket can be seen as a more robust option. MLS gaskets are more wear-resistant and can offer an extended service life over composite gaskets.
It’s not uncommon to see oil leaking from a high-mileage boxer engine, or any other style of engine for that matter. While not overly common, valve-cover gaskets, camshaft seals and rear main seals tend to be the most likely sources. If the engine-oil level drops between services, but there are no external leaks present, it’s time to look inward. Worn turbo seals, piston rings or a faulty PCV system can cause oil consumption.
The all-wheel-drive system in Subarus can be vulnerable to unintended drivetrain movement or free play. For example, a worn pair of engine mounts could cause the drivetrain to shift from side to side while driving. This places added stress onto other components such as CV axles and bearings. If a customer is in your store asking about a replacement CV axle, try to help them figure out what caused the axle to wear out in the first place. You may be able to help them to treat the cause, not the symptom.
Timing belts and water pumps are routine maintenance items on boxer engines. Replacement intervals vary based on the model and the production year; be sure to check the OE service information for specifics. We suggest selling a complete timing-belt replacement kit with the belt, water pump and all other required components to get the job done.
Finally, be on the lookout for worn, cracked rubber hoses in the engine bay. Years of heat cycling will cause rubber hoses to break down, become brittle and crack. The same goes for plastic components such as radiator end tanks, reservoirs, plastic hose fittings and more.
It seems to me that Subaru has found a winning formula, and the automaker continues to stay true to it. I’m excited to see what the next decade will bring for this pioneering Japanese automaker.
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