Why it Broke: To understand leaf spring failure, you must first wrap your mind around the basics of leaf-spring behavior. A leaf spring's basic job is to absorb and store mechanical energy, which in turn is transformed into heat. Of course, heat is the leaf pack's archenemy because heat causes fatigue, which eventually leads to failure. Ever notice how leaf springs found under Baja race vehicles are comprised of many more individual leaves than a traditional spring pack? This is because fast desert driving creates far more heat than everyday terra firma. Excessive heat requires increased mass to dissipate and control. Without this extra mass, the springs get hot and crack, causing what you see here.
Solution: Many companies build bombproof leaf springs designed to handle increased heat. Deaver Spring is one of the more well-known of the bunch. Deaver offers custom-built leaf packs for just about everything on rubber tires. Old Man EMU, a division of ARB, also offers leaf packs that are virtually indestructible, thanks to some very high-tech manufacturing processes. Look for catch phrases like "shot peening," "fully-scragged" or "military-wrap" when investigating leaf springs; you'll be glad you did.
Why it Broke: Hubs are items for which you really have to understand the forces involved. We expect them to transmit gobs of torque from a little, tiny axleshaft to a wheel mounting surface that is, in most cases, attached to a tire that is much bigger than originally intended. Issues arise when shock loads occur.
Solution: On some vehicles like Jeeps, factory hubs are upgradeable to versions constructed of premium materials. Warn, Superwinch, and now Dynatrac offer hubs that stand up to a ton of abuse without issue. If you break those, the next option to consider is drive flanges. Drive flanges typically are found in competition rigs and trailer queens because they provide a solid connection between the axleshafts and the tires. Warn and Dynatrac also offer these.
Why it Broke: Internal engine components are not immune to breakage. The intake valve shown here was removed after the Chevy engine it came out of started making a strange sound and refused to run smoothly. As it turns out, this valve had a manufacturer defect that caused the problem.
Solution: High-strength valves made from stainless steel are really the way to go. We're always on the lookout for better options, but when you consider what you get for the price, stainless-steel valves are the best value. Edelbrock offers one-piece, swirl-polished, hardened-tip stainless valves for most applications.
Why it Broke: Most of the time, failures associated with structural tubing are the result of inadequate design and or misapplication of materials. In this case, the failure occurred on an area where three tubes intersect. The force that caused this chromoly tubing to crack was not taken into account when the chassis builder designed it. Chassis building is all about design. The use of triangles is very important, and when each tube is welded together, one must be very careful not to fatigue the material by adding too much heat.
Solution: A few simple gussets may have prevented this failure by distributing the stress loads outward, across a larger section of the material. Also, welding a little bit at a time can help reduce the likelihood of fatigue. Never underestimate the forces that a chassis is likely to experience on the trail. A little extra material can make the difference between packing it up or taking it out for another ride. FW
Why it Broke: Limited slips, some lockers, and stock-style differential carriers usually fail when too much stress causes the carrier housing to break apart or crack. Most of the time, this can be attributed to massive tires and high horsepower. Other differential failures can occur while towing heavy loads, or if the differential doesn't get the proper lubrication.
Solution: Stick to products with a proven track record. Yukon Gear offers awesome full spools for the trail-only operator. Eaton's Detroit Locker and Truetrac differentials are about as bombproof as they come. Stay away from differentials with clutches and other moving parts. Simple is better when it comes to differentials.