There comes a time when venturing off road that leaf springs do fail. Your day of 4x4 fun comes to an abrupt end.
Such an occurrence recently happened to me. Luckily, the main leaf spring did not completely break and I was able to make it home after some scrounging and rigging a "splint" to keep the spring from flexing and completing the break.
Time for a little break analysis. For starters, the springs were new when installed with the spring-over lift in November and had seen 6 days of on the trail use. Springs are designed to flex and should offer trouble free action over an extended life. Spring failure can result from abnormal stress or metal weakness due to improper tempering.
Normal design has the spring in a fixed location on one point of the frame and a movable mount for the opposite end. For leaf spring vehicles, the fixed mount point is towards the center of the vehicle. As my spring failure involved a front spring, I will focus on the design and option modifications for front springs.
First, spring hangers are a common failure item. JKS Slick Rock Spring Hangers
provide an upgrade component to address the stock weakness. The Slick Rock Spring Hanger provides a solid mounting point for the spring shackle. It is the movement point for the front spring.
Second, The rearward spring hanger (providing the fixed mounting point) is subject to weld cracks and elongation of the bolt mounting holes.
I had previously installed the Slick Rock hangers and had the rearward hanger re-welded. Plus, due to elongation of the holes, Grade 8 washers were welded on to provide a reinforced mounting hole for the spring.
The spring failure occurred at the rear of the front spring, about 6-8 inches from the fixed spring hanger point. In reviewing the forces applied, under articulation conditions, the tire (and axle) are forced back towards the fixed point. It appears that this was the basic cause of the failure.
In other words, the spring was bending rather than flexing. The result was the spring began cracking.
As this happened on the trail and more than a few miles from a repair point, it set the stage for some critical actions. Basically, get off the trail and get to a place where repairs can be made.
In my instance, the first action was to immobilize the area to prevent further bending that would complete break. First though was the Hi-Lift jack. That may have worked with the rear leaf.
Due to the design of the spring hangers on the front, I could not get a Hi-Lift into position between the spring hangers. Remember, I am dealing with a spring-over lift where the distance between the springs hangers is about 44 inches. The Hi-Lift jack is 48 inches.
I was able to get a tire-iron into position over the break. However, I had no way to clamp it to the spring to prevent the spring from flexing. So, given enough off-roaders and the variety of things they carry, a little gadget did show up that provided the basis for the necessary “splint”.
A Hi-Lift jack is truly multi-functional and several accessories are available. One accessory assists in using the Hi-Lift as a winch. The little piece of metal fit over the spring. I was able to slip a wrench between it and the spring and clamp it down. To assist the splint and reduce potential of movement, several stainless steel hose clamps were tightened into position.
The test was being able to drive back to camp with no problem. The real test (and decision) was to risk flat towing it home. Would the temporary repair hold?
Once at camp, a close inspection showed no movement with the temporary repair. Next step was to reinforce the splint to allow the jeep to be towed home for repair. That was done by wedging a piece of wood between the spring and the frame and using a ratchet strap to hold it in place. This limited the downward travel (and flexing) of the axle and spring.
Long story short, I did tow the jeep home and to the shop for final repairs. The repair and potential modifications will be tested at Desert Safari. Watch for Part 2 of “When springs break...”
Until then, I did locate an emergency spring repair kit that will now be a part of my on-board emergency kit. The emergency repair kit, produced by Hellwig, has been discontinued.