Weak mounts

If you read my last blog you already know about the different options for lifting the most popular Jeep suspensions, one thing that remains a constant among all of them is there weak axle side lower control arm mounts (the frame side mounts have their own issues as well) The problem with the lower control arm mounts, specifically in the front is that they hang below the axle tube where they are susceptible to damage from trail obstacles. Couple this with a weak stamped steel design from the factory, with no type of skid plate and it's easy to see why most people end up bending or breaking these mounts.

This is exactly what happened to a good friend of mine on our clubs annual Easter trip to Windrock Park last year; and in true wheeler fashion he waited until the week before this years trip to properly fix it, due to work schedules and a busy family life it left me fabricating him a new mount less than 12 hours before his departure!

This lower control arm mount was ripped completely off by a rock, it was then temporarily welded back on.

There are several options out there to replace and upgrade the factory mounts, however with a little patience and some 3/16" steel you can throw one together in a couple of hours. For this repair I first cut the old bent up one off, it was pretty beat up, but I was still able to use it as a rough base for the new one. Be sure to clean all of the remnants of the old mount from the axle, remove all paint and rust from the entire area so that when you weld the new one on it will be a good solid weld.




I traced both sides onto a piece of cardboard, and added a little extra material on the axle side since that is where I cut it off. Once I cut out the template I also added the bolt hole location using the back of the original mount as the guide.

I then "bolted" it into the lower control arm and swung it up into place and began the trimming process, trimming a small amount at a time until it fits in the factory location correctly. It is important to account for the top plate in this process, however if need be you can trim the tops of the side plates once they are all fit up.

Once you are satisfied with the way the cardboard fits, it's time to transfer it to the steel. I have the benefit of a plasma cutter in our shop, however you could do this with an oxy fuel torch, a bandsaw, or even a grinder with a cut-off wheel. You will then need to transfer the bolt hole location and drill those through as well, keep in mind that you don't want to make these holes any larger than need be or you will end up with a lot of slop which could lead to death wobble.

Be sure to de-bur everything real good, you may be doing this in your driveway, or your poorly equipped garage, but it doesn't need to look like it, take some time to make it look good now so you won't be embarrassed to show it off to your buddies later.

Now start the trimming process over, this time with the steel parts, fit your pieces together using the control arm to hold it all together, don't tighten the bolt to much or you final gap will be to tight. Take your time, make sure your gaps are as tight as possible. Tack all the pieces in but be sure the tacks are in an area that can be cut out if you aren't happy with the fitment. Again, don't rush this, make sure all the pieces are fit correctly, and the lower control arm is at the correct angle; once you are 100% happy with the fitment add a few more tacks to lock it all in place. Remove the lower control arm from your new mount so you don't melt the bushing, plus this allows you to access the inside of the mount. Now weld that sucker in! 

I also added a small plate to the front side of the mount (That Jeep should have included from the factory) this acts as a skid plate, and helps to stiffen the mount to help keep it from folding over if you hit a rock. I added one to the factory mount too in hopes of keeping it in one piece so I don't need to do this again after the next trip out.

Be sure to paint everything before reassembling to keep the rust

Jeep suspension comparison

There's lots of options for lifting your coil sprung Jeep, but what is the best option for you? In this blog I will help answer that question by discussing the differences in each. This is relevant to several different models of Jeep's, the coil and link design was first released in the XJ (Cherokee), MJ (Comanche), and ZJ (Grand Cherokee) platforms, and then reworked slightly in the TJ (Wrangler) The photos in this write up were taken from the XJ, and ZJ models... Because that's what we have in the shop right now.

Stock- 

I'll be honest, the engineers actually did a pretty good job right from the factory with this suspension, on the road it rides nice and smooth, off road it flexes well, and is well suited for light duty wheeling and fire road cruising. If your only plan for your Jeep is cruising backroads that are slightly to rough for your minivan, you will probably be fine with this. I would also include "Budget boosts" in this category, a budget boost is simply adding some spacers to the top of the coil spring to increase ride height; in moderation they work, but should never go over the 2" mark, and you need to keep in mind your shocks will be your limiting factor. 

As you can see the control arms are pretty short, and not very beefy since they are just stamped steel, serious off road use, and big tires will destroy these little guys. 

Another issue to keep in mind with these control arms, especially if you plan to use them in a lifted configuration, is that the angle of these are designed to provide the best performance AT FACTORY HEIGHT! meaning that if you use these with taller springs or budget boost spacers you will be using them at a much steeper angle than designed, this will result in a rough ride as tires will be trying to shove them straight up rather than in an arc.

Short Arm Lift-

This is your "basic" suspension lift that most guys start out with, it replaces the control arms with tubular pieces which often have flex joints at one end to help them move more freely, longer shocks to allow the suspension to flex further, and longer springs to increase ride height. Because these are designed as a system ride quality normally stays fairly comfortable (Some companies have better springs and shocks) This is a great option for the guy that wants to actually hit some trails, you won't be ready for rock racing, but you'll be able to go play in the woods and have a good time. RC short arm kits

4" suspension at ride height 18.3 degrees

4" Suspension at full droop 33.2 degrees

The issue with this set up goes back to the angle issue I described in the stock setup, although the new control arms help correct this problem to some extent, you are still using the stock location for the mounts, meaning the angles still won't allow for large lift heights; a short arm lift is usually good to about 4-5" of lift. Some guys try to stack budget boosts on top of their 4" lift springs and think they are badasses, really they are dumbasses. Doing this throws your control arm angles WAY off, plus your shocks are going to be to short, and because your angles are to steep it is going to move your tires towards the back of the wheel well, even if it doesn't rub you'll look like an idiot. This is also a good way to rip your factory mounts off the frame or the axle.  

Long Arms-

This is where you start to play with the big boys, all of those issues above, GONE! You simply cut out all the factory frame mounts, install new cross-member mounts, and install your much longer and stronger than factory control arms. With this setup you can get away with 7-10" of lift, with plenty of adjustment to keep your angles happy, on road ride quality will probably be better than the factory since at ride height your control arms see about 1/4 of the angular movement for the same lateral distance. Sure they may cost a lot more up front, but they are cheaper than buying a BB only to realize it's not enough, then going to short arms only to outgrow them in a year or two, and THEN finally order the long arms that you should have bought in the first place (This is literally what most of us do, we're all idiots)

The Iron Rock Off Road kit utilizes an Iron-Y design which eliminates the upper control arms

So what's the downside to a long arm set up? Other than the cost of the kit, not much. These kits are engineered to perform, they are strong, and flex like crazy. And as you can see in the photos the angular change from ride height to full droop is much less than the short arm lift.

7" Lift at ride height 12.5 degrees

7" lift at full droop 26.6 degrees

Full Custom-

So where do you go from Long arms? What do you do if you want LOTS of suspension travel, and the ability to adjust how your suspension reacts? Rip out all the factory stuff, and throw down some cash on custom links, mounts, and either coil over shocks, or ORI struts, do a BUNCH of calculations, change your design 5 times before settling on the one that will fit your space, and ride characteristics. 

This option is not for the guy that just wants to take the kids out and splash through some mud puddles, this is for the guy that is fully committed to the hobby, he's full blown addicted to the feeling of hitting the hard line and making it.