|[an error occurred while processing this directive]||Short Cuts|
By: Berkeley Johnston - 10/2001
Installing Old Man Emu JCXL Add-a-Leaf Springs to a Cherokee XJ
About a year after installing the original Old Man Emu and Tera Flex lift, the Cherokee is sagging. The rear leafs have settled an inch and the extra weight we're carrying now makes it worse. The camping gear and spare parts weigh far more than I would have guessed. I might add a much bigger lift within a year, so I started looking for a short term solution.
|The full-length OME AAL becomes the second leaf in the spring pack. The overall spring rate is increased by 20% which helps tame the heavy loads. Unlike the other leafs in the OME pack, it does not come with a greasable nylon pad.|
Switch to new, taller leaf packs? Too expensive. Add-a-leafs would be less expensive, but they have a bad reputation. Lift blocks are really cheap, but they have a bad reputation, too. The solution I decided on was to insert an OME Add-a-Leaf into my existing spring pack, adding some lift and increasing the spring rate.
Sagging. What to do?
When I first spec'd the suspension, I didn't take into account the weight I would be carrying. I probably wouldn't have figured on carrying as much weight as I do anyway. Things change. The Old Man Emu (OME) leaf spring pack is great when the XJ is empty or nearly so. Usually, though, we've got the family of five, the 130 pound Newfoundland dog, spare parts, and camping gear. This weight, coupled with the extra settling in the rear, lead me to think about finding some way to fix the problem. Perhaps I could add an additional spring in the pack, or add blocks to regain the lost inch of lift.
Honestly, like most 4x4 rookies, I walked into my initial lift purchase half-blind. I really didn't know what I was getting when I plunked down the money. I'm sure Chet explained everything, but without in-the-field experience, a lot of the information went over my head. I didn't know it at the time, but there are four standard OME choices for the XJ. I received the JC1B packs, the shortest (least lift) and softest of the bunch. The JC2A is about 10mm taller, and is stiffer. ("2" is taller than "1" and "A" packs are stiffer than "B" packs.) After a couple of years of wheeling, I've got a grid for all the technical details. Enter Rocky Road Outfitters.
The knowledgeable folks at Rocky Road Outfitters helped me choose a path to eliminate some of the problems that have emerged as the family has taken more and more trips. And they helped debunk some of the myths surrounding the add-a-leaf and lift block debate. Rocky Road owner Glenn Wakefield is an active, long-time supporter of the 4x4 community. His staff knows what they sell and are more than helpful. They provided the above information about the OME spring packs, and that's the kind of detailed info I now look for in a supplier. You can't make the right decision without the correct information. I've spent the most time discussing problems and plans with RRO staffer Von. Even after months, we can pick up the conversation where we left off. He remembers my vehicle, my plans, etc., and I just update him on any changes. Not having to describe the XJ with every call saves us both a lot of time.
Add-a-leafs have a poor reputation and it's partly deserved. A really cheap path to a quick lift is to insert an AAL into an existing stock spring pack. This works at first, but is doomed to fail quickly. That single spring has got to provide all the vehicle lift plus it has to counter the forces of the tired stock springs. No way. Sooner or later the lift will be gone, and the money wasted.
My original spring packs, OME #JC1B, were too low and too soft when the XJ was fully loaded. The stiffer, taller #JC2A leaf pack could be what I really need, but instead of buying an entire new leaf pack, RRO suggested adding either an OME add-a-leaf, or a lift block, or both. The OME JCXL is an AAL designed to compliment my existing pack, not fight it. Von and I knew that the JCXL would add extra spring rate... about 20% more. That extra resistance to droop would provide part of my solution.
Ultimate Lift Blocks
|RRO's shimmed lift blocks are welded together in 1/2" increments. I've done some custom milling which can be seen along with blue marking dye.|
Lift blocks have a bad reputation for mainly two reasons. First, they are usually made from aluminum. Aluminum blocks, especially the more common hollow versions, don't have the strength to survive serious off-roading. Blocks also worsen any spring wrap problems. Excessive block lifts also cause the spring to S-curve. The extra lever-arm created by the blocks--often 3" or more--allows the forces entering through the drive shaft to twist the axle, causing the leafs to bend into (and eventually stay permanently as) an S-shape. The higher the blocks, the worse the problem can be.
Like many other 4x4 shops, RRO sells lift blocks. What RRO does differently, however, is they make the blocks from steel. You decide what lift you need in increments of 1/2" and whether or not you need a shim for an angle change. Three and five degree shims are standard, but any degree can be ordered for no extra cost. Rocky Road Outfitters welds the whole set together. Once you bolt the assembly to the spring pack, it's there to stay. There won't be any block disentegration, or loose springs like standard aluminum blocks can give you.
RRO runs short blocks in their vehicles and like them. They don't see premature spring failure with just an inch or so of block lift.
Once I received my beefy blocks from RRO, I modified them. Perhaps unnecessary, but I was experimenting. You'll notice in the image of the blocks that they've been milled on the corners at an angle. I wanted to change the leaf mounting surface size from 6" to 4" just like the stock spring pads. The extra pad width of the RRO steel blocks (6") would help prevent spring wrap. I figured, though, that the extra 2" of width would also hinder the springs from flexing along their entire length, possibly causing premature spring failure. Maybe not. In any case, I can either mount the blocks "shim down" for the smaller 4" pad width, or "shim up" to get the wrap-preventing 6" mounting surface.
The JCXL should also add lift, but not very much, so I ordered both the extra leafs and one inch blocks. I also ordered integrated steel shims to replace my aluminum ones.
Parts and Assembly
The original u-bolts were maxed out in length, so I bought a longer set at NAPA. While there, I picked up a longer leaf spring bolt, the one in the center of the spring pack that keeps the leafs together. The new bolt would be long enough to fasten the extra leaf and the shimmed lift block to the pack.
2 - Old Man Emu JCXL leafs
4 - NAPA U-bolt, #650-4023, 7/16" Dia., 2 3/4" I.D., 6 3/4" Length, Round
2 - NAPA leaf spring bolts
8 - 7/16" flat washers
Lift heights before add-a-leafs:
Empty: 34 3/4" front, 33 3/4" rear. It's sagging by one inch in the rear.
Weight: 34 7/8" front, 32 3/8" rear. The weight dropped the rear by 1 3/8 inches.
Assembly was easy. Follow the instructions previously published about the initial rear spring replacement. Once the OME spring pack is removed, disassemble it by removing the center bolt. Now is a good time to clean and re-grease the leafs. Reassemble the pack making the new JCXL the second leaf, just under the main leaf.
Lift heights after adding the JCXL springs
Empty: 34 3/4" front, 35 1/8" rear. The JCXL leafs added 1 3/8" lift.
Weight: 34 7/8" front, 34" rear. With the same weight, sag is reduced from 1 3/8" to 1 1/8" inches. 20% less.
Surprisingly, the JCXL added 1 3/8" lift to the rear, so I am not using the blocks for now. I suppose I shouldn't have been surprised by the added lift, but we figured the new leafs would not add that much lift, only add spring rate. The springs will probably settle after a few trips and some of that 1 3/8" will be lost.
I wasn't expecting the lift gain with the JCXL springs, but I'm pleased. They'll probably sag in the coming months... we'll see. I don't need the blocks, but I'll keep them around just in case. (Update: After five months and a couple of long, hard trails... no appreciable sag. Cool.)
Ride Quality and Performance
It was a shock to hit the road with the new suspension. The AAL made the ride noticibly stiffer and not at all pleasant. A few days later, however, I don't notice the extra harshness. I also suspect that the ride is still very nice, relatively speaking, and it still lives up to OME's reputation. Loaded up, the XJ is much better. It doesn't wallow on the freeway like it used to. I'm very pleased.
Off the road, I'm still flexing like I'm used to. No problems there. In fact, the AALs have helped a lot. Previously, I would bang the rear bumper coming off of most rocks. The extra lift and spring rate of the improved leaf pack prevents most of the teeth-rattling bang that was previously so common. Much better.
Inexperience during my first purchase presented me with a suspension problem. Rocky Road Outfitters and a set of OME add-a-leafs helped me solve it.