It has happened to all of us-that unforgettable sound you loathe to hear while out enjoying a day on the trail. Sometimes it is a sharp "snap" or a loud "pop." Other times it is a silent hush that goes undetected until its source prohibits forward progression. In any case, it usually means your day of fun is over, and the next few hours will probably entail wrenching, if not worse.
Breaking down can be a really frustrating experience. Replacing expensive parts on the side of the trail typically involves some degree of discomfort, time wasted, and humiliation that no amount of cold beer can abort. Over the years, we've seen tons of carnage on all kinds of rigs. The only obvious parallel we can identify in each scenario is the fact that broken parts suck. However, upon closer scrutiny, every shattered part tells a story. For this reason we've compiled a summary of 10 common failures and their causes. In addition, we've provided suggestions on how to beef-up each failed component.
Why it Broke: Axleshafts fail when torque spikes occur. In some cases, fatigue over time can weaken the shaft, causing hairline fractures which eventually lead to catastrophic failure. Again, this type of carnage is usually a result of bigger tires and a heavy use of throttle.
Solution: Many solutions exist in the form of high-strength aftermarket shafts. Common buzzwords to look for are 300M and 4130 chromoly. Cryogen treatment also reduces the likelihood of a broken axle; however, nothing works better than simple overengineering. Consider the weight of your rig before swapping in new axlehousings. Military-spec 2 1/2-ton axles seem to be gaining popularity these days, but in most cases simply upgrading from 33-spline Dana 60 shafts to a set of 35- or 40-spline, or better yet, 300M shafts will do the trick. Dynatrac, CTM, Yukon Gear, and Superior Axle all offer these types of upgrades for the ever-popular Dana 60 axle.
Why it Broke: Designed to be the weakest link of any drivetrain, broken U-joints are probably the most common form of carnage we see. Typical failures are caused by over-torque situations likely due to excessive throttle, or in some cases, extreme shock loads.
Solution: Every U-joint has a specific torque rating or spec that it will stand up to. Most manufacturers don't list this numerical value for fear that variances between production runs would give consumers leverage in warranty disputes. Others, like CTM, Longfield, and Yukon Gear go the extra mile to ensure that every U-joint can perform consistently under well-specified torque loads. Of course, these premium U-joints typically carry a much higher price tag as well. For those of you who don't want to drop the cash on high-strength joints, consider smaller tires and/or a lighter right foot. Also keep in mind that a front axle U-joint is weakest when the wheels are turned to full lock.
Why it Broke: This commonly overlooked part is super important. Trust us, a broken sector shaft is one thing you never want to deal with by yourself. Essentially the backbone of a steering system, this part tells your drag link and tie rod where to go. Without it, your steering is useless. Carnage is usually the result of much larger tires combined with stronger-than-stock tie rods.
Solution: The best way to reduce stress loads on a sector shaft is to add hydro-assist to your steering system. Several vendors survive by offering complete kits for just about any rig. Our advice is to take a good long look at all the options before forking over the cash for a kit, and in the end you'll be glad that you did. Check out Howe, PSC, West Texas Offroad, and Off Road Unlimited for more information about vehicle-specific kits.
Why it Broke: Steering knuckles fail under a variety of conditions. Most often it is caused by severe shock loads such as jumping and landing on one tire, or striking a stationary object with a tire unintentionally. Other cases involve improper steering geometry and/or overly powerful hydraulic rams. The real bummer with broken knuckles is that options are limited when it comes to upgrades.
Solution: For Dana 44 and 60 axles, check out Dedenbear or Spyder Trax. Both of these companies build replacement knuckles that are much stronger than stock.
Why it Broke: Improper application is by far the most common reason we see antisway and torsion bars snap. Fatigue can also play an important role, but more often than not it is a simple lack of proper engineering that causes issues here. These bars are designed to twist at a specific rate within a specified range of motion. Add increased leverage or greater rotational movement, and you're going to run into problems. Commonly, this occurs when flex is increased without changing the length of antisway-bar end levers.
Solution: Antisway bars require a mathematical process to be set up correctly. We suggest that you contact a professional like Speedway Engineering, Teraflex, or Currie Enterprises. Torsion bars are available in many different rates and materials, and again, each application has a different set of parameters that determines its application. Most suspension companies offer advice for customers with torsion-bar suspension systems.