Build Your Own High-Clearance U-Bolt Plates
Tuning your leaf-sprung suspension
We've touted the benefits of leaf spring suspensions before. Fact is they follow the KISS rule of engineering pretty well (Keep It Simple, Stupid). The KISS rule helps you and your 4x4 rig slide under the ever-watchful eyes of Murphy's Law, which says something to the effect of, "If something can go wrong, it will."
Leaf springs are simple and do many jobs that otherwise have to be done by multiple components. One problem with leaf spring, or at least those mounted to the axle in the spring-under configuration, is that the leaf spring retaining parts, namely the U-bolts and spring plates, hang low under the axle, generally adding a low-hanging jagged structure to grab onto rocks and other trail obstacles. The ends of the U-bolts act like fingers grabbing rocks and roots and logs, stopping your 4x4.
But there is something you can do about it to prevent this, or at least minimize it. First there are some U-bolt spring plates that have skidplates built in, and that's great, but it still hangs low. Also you can do a U-bolt flip kit, which sometimes can be found in the aftermarket. Lastly, you can occasionally buy high-clearance U-bolt plates (like these from RuffStuff Specialties) or build some for yourself. That's what we're going to show you today.
Building High-Clearance U-bolt Plates for 2-inch Springs
For reasons that are hard to explain, we've decided to fix up this rusty, rotten 1962 CJ-5. It's had a hard life, and it shows, but for inexplicable reasons it speaks to us. Our plan is to build an understated old Jeep with lots of subtle tricks built in. We'll call it our cheater rig. Earlier we showed you how we mounted the leaf springs on this Jeep. We decided to reuse the factory CJ-5 rear springs and are running a pair of flatfender rear springs up front (because they are just a bit longer than the CJ-5 fronts). Both of these pairs of springs are 2 inch wide. That means the high-clearance U-bolt plates from RuffStuff Specialties above won't work. Instead we came up with a plan a design. We'll start with a length of receiver hitch stock from our local steel supply, Advance Metal Sales in Phoenix, Arizona. We cut the tube to 5-inch lengths and copped off one side (usually the side with the rolled seam in it). In the opposite side, or the bottom of these four parts, we drill a 9/16 hole. To that we add four each 1-inch-long chunks of 1 x 0.188 wall DOM tubing, but first we have to cut them.
The parts that make up our High-Clearance U-bolt Plates
With the assembled pieces of our high-clearance U-bolt plates all prepped, we can get ready to weld them up. First we use our pneumatic angle grinder with an abrasive disc to clean the scale off the tubing and the 1-inch sleeves so we are sure the welds will be clean and strong. These are parts you don't want coming apart at any time once on the vehicle.
Welding the Spring Plates together
We started welding the high-clearance U-bolt plates by tack-welding the sleeves in place with the open end of the square tube and one end of the sleeves facing down on our welding table. Use the U-bolt to locate the sleeves and then tack. Then check to ensure the sleeves are true and that the U-bolts can pass all the way through the sleeves. With that done you can turn your welder up to kill and burn the bits together. We set our Miller Electric Multimatic 220 to 5/16 with 0.030 wire using the MIG process and laid down some thick welds along the sides of the sleeves. You want to make sure you don't build up weld on the flat of the sleeves because nuts and washers will have to ride there and you don't want to side-load the U-bolts. We then switched over to TIG on the Multimatic 220, switched from c25 to 100 percent argon, and melted the flat surfaces of the sleeves to the body of the plate without adding much filler rod. Again, we want this surface to be flat. If you don't feel confident with heavy welds on 3/16- and 1/4-inch steel, don't do this. If these parts come apart, people can easily die, and the weight of that's on the shoulders of the person welding these custom parts together.
Our Finished High-Clearance U-bolt Plates
Here's the final product, albeit not fully tightened yet. We will trim down the U-bolt ends once we set the rear pinion angle for good, are sure we don't need to add shims to the front axle, and once we've fully torqued the U-bolts in place. We also may add some bits of 1/8-inch steel plate between the sides of the tube and the leaf spring because there is a bit more of a gap than we'd like to see between the Hitch stock and the sides of the leaf springs. As you can see, the U-bolt ends and U-bolt plates hang just a 1/4 inch below the bottom of the leaf springs. That's a lot better than having the plate, washers, nuts, and part of the U-bolt hanging out below them. More cheats to come, so keep your eyes peeled.