2012 Jeep Wrangler: Installing a Mopar Stage 3 Lift Kit With Fox Racing Shox, Rear
March 18, 2012
Break time is over. It's time to install the rear half of the Mopar Stage 3 Lift Kit with Fox Racing Shox on our 2012 Jeep Wrangler.
The front suspension installation, Part I of our story, appears one blog below this one. The front end installation involved the drilling of 14 holes, the mechanized removal of two bump stops and the intentional destruction of two brackets. There's not near as much metal manipulation back here. This end is a cake walk in comparison.
First I need to reposition the two tall jack stands and lower the Jeep's rear axle onto them with our Rotary lift until the axle's weight is supported and the rear shocks are compressed ever so slightly.
The rear shocks are the component that defines how far the axle can hang, so they need to come off right away.
The stabilizer links are next to go. They're destined to be replaced with longer ones, so they can go in the trash can alongside the shocks.
Like the front, the rear axle is located by 4 trailing links and a lateral track bar (a.k.a. Panhard bar.) Once again their 10 bolts are to be loosened, but not removed.
The sole exception is the bolt on the left-hand end of the track bar (yellow.) It gets taken out so the track bar can hang out of the way for the next few steps.
The parking brake cables will still be long enough once the 3-inch Mopar lift is installed, but only after I remove and discard the factory retaining bracket so they can hang down a bit more.
The brake line retaining brackets are disconnected, too, but no parts will be thrown away here.
Once the brake brackets are loose it's time to raise the lift enough to take the weight off the coil springs and open up a gap so I can pull them out. The rear differential breather hose (yellow) doesn't like it much, but I'll deal with that later on.
The rubber spring cushion seen on the uppermost coil will be reused, but the springs are now boat anchors.
Now the lower trailing links can be removed and replaced. The new ones are longer in order to keep the rear differential pinion angle at the proper angle with respect to the driveshaft. The extra length also keeps the wheelbase from shrinking.
Both ends of the one on the passenger side can be bolted (loosely,) but the one of the driver side needs to hang out for a couple steps while I do something else with its rear mounting bracket.
This new bracket moves the left pointing point of the track bar up three inches so it will run at the same angle (nearly flat) after the three inch lift is installed.
One of its mounting holes (yellow) will share the bolt used to mount the link we saw in the last photo.
Here the trailing link has been installed with its mounting bolt also running through the new track bar bracket. Meanwhile, I'm installing a u-bolt around the axle tube to hold the other end of the track bar bracket in place.
Unlike the suspension link bolts, the u-bolts can be torqued to their final tightening spec right now.
Now it's time to re-mount the left end of the track bar in the new bracket.
New upper trailing links go in next. Keep your eye on the urethane bump stop because it's about to disappear.
No, the old bump stop is not in there. I removed it before installing these new cups. They snap in place over the old bump stop retaining bracket.
A new longer microcellular urethane bump stop will snap into the original bracket; the cup's job is to keep it lined up vertically. Silicone spray helps it snap into place.
But it still takes persistence to finally snap it home.
Things are moving along quickly now. It's already time for the new longer stabilizer bar links to go on.
I've bragged on the Craftsman Max Axxes external drive socket set before as a good deep socket alternative, but this is brilliant. Stabilizer bar ball joints and many strut tops feature an internal hex you're supposed to hold still while you tighten the nut, and it's always a bit of a hassle.
Ratcheting end wrenches work, too, but you have to buy them one size at a time. Owning a whole range of them is not cheap. The Max Axxess socket set is a lot less expensive, and it works great as a regular ratchet, a deep socket alternative, as well as this particular situation.
These brake bracket extensions drop the hoses down so they'll still work with the lifted suspension. I haven't cracked open any brake lines, so they'll be no brake bleeding later.
I do have to reshape the hard part of the brake line by hand to make sure it clears the stabilizer bar end link, though.
This is moving along fast. It's already time to install the rear springs.
The lower end of the spring drops easily onto its seat.
Mopar's kit comes with the special tool that helps get a retaining nut up in behind the spring seat...
...so I can install this spring retainer.
This spring retainer holds the spring in place at the top, and the bolt goes into an existing hole. That's right; I still haven't cut or drilled anything at the rear axle.
Here's another of those Nutserts we saw during the front suspension installation. This one goes into another existing hole in the frame for the rear limiting strap.
You can bet what's coming next.
That's right, the rear limit strap needs a hole to connect to, so I've got to make one. Two, actually, because I'm doing all of this on the other side, too. But you knew that.
Now I can tighten the lower limit strap bolt. Incidentally, the hole I drilled made it necessary to remove one of two clips (orange) holding the ABS wire in place.
On an unrelated note, all of the trailing arm bushing bolts, front and rear, get these rectangular positioning shims where they bolt to the axle. Mopar says these lock the links into just the right position so no wheel alignment is necessary after the kit is installed.
The only adjustment needed is a small change in the length of the drag link to re-center the steering wheel, and that's a cosmetic adjustment that can be eyeballed.
Now it's time to install the Fox Racing Shox. There's a simple trick that makes it easy: compress the shock fully on the floor, then quickly swing it into the lower bracket and let the internal gas pressure "grow" the shock into the upper mount.
One of the last steps in the process is the installation of a new rectangular landing pad for the rear bump stop. It bolts into existing holes.
This is probably my favorite picture of the bunch. Clockwise from the left we have: upper trailing link (with the lower one partially hidden below); limit strap; ABS signal wire; bump stop (with the spring partially hidden behind); track bar and in new bracket; Fox Racing Shock; rubber brake hose; stabilizer bar and link.
Can it be? Are we done? Not quite. There are a few more things to take care of. But for those we must lift the Jeep high up on the lift and retire our trusty orange floor jacks.
There's still the matter of reconnecting the driveshaft, and there's a small issue. A 3-inch suspension lift requires the driveshaft to hang down at a steeper angle. But here it's hitting the exhaust system.
This is only an issue with 2012 Wranglers like ours, the ones with the new Pentastar V6 engine. 2007-2011 JKs with the older engine don't have the same exhaust routing and there's no interference. The next couple of steps apply only to 2012 JK Wranglers (and later if you're reading this in the future.)
These are exhaust spacers. It's hard to tell, but the one on the left is a little longer. These parts are fairly new, and their installation isn't described in the draft set of instructions I'm working from. So, after careful study of the parts and the vehicle, I'm making this up as I go along.
They bolt to the forward legs of the central y-pipe in order to push it back and allow the driveshaft to clear. But pushing the y-pipe back has knock-on effects farther downstream. Theoretically, the rear pipes and the muffler would also get pushed back the length of the spacers, and I figured that would put pressure on the exhaust hangers and move the pipe close to my new springs.
I decided a little adjustment is in order.
For the pipe to go back this indexing nub has to come off.
Scott and I had this plan for a dramatic action shot, with me swinging a hammer while holding a chisel. While he went for another lens I made a gentle exploratory tap ... and it came right off. Oh well.
That blue tape contains a scratch mark for the next step.
Yes, I'm cutting off a bit of the pipe. The dimension I chose corresponds to the length of the shorter of the two spacers -- the reason for that will become clear in a moment.
Mopar later told me this cut wasn't necessary, that removing the nub was enough on it's own and I could do that with the y-pipe still in the car. Removing the nub, they say, allows the y-pipe to telescope into the rear pipe a little bit, and the flex in the rubber hangars would make up the rest.
Maybe they're right. (Of course they're right.) But this way isn't wrong, it's just more time consuming. My exhaust hangars will hang exactly as they did before and the pipe slip-joint will engage exactly the same amount.
The long spacer goes on the passenger side, where the exhaust pipe runs at a downward angle. Because of this angle, only a portion of its length contributes to a shift to the rear. And the magnitude of that shift is exactly equal to...
...the length of the short spacer, which goes on the driver side where the pipe points straight back. And that's why the length of my cut equaled the length of the short spacer.
Notice how the y-pipe's cross tube runs just ahead of the frame cross member. It's close, but there's still a good half inch of daylight.
Now the driveshaft can go back together. But first I need to put a dab of fresh thread locking compound on the bolts.
This concludes the driveshaft detour part of our show.
Here I'm splicing in an additional section of breather hose I bought at my local auto parts store. Technically speaking I bought fuel line hose, but it's the same size. Mopar later told me it's also possible to unfasten the upper end of the hose from its factory mount and reposition it with tie-wraps, but my hands wouldn't fit up in there.
All of the trailing arm and track bar bushings get tightened and torqued once the Jeep is back down on its tires. I'll spend a lot of time crawling around underneath to get it done, but three extra inches of newfound lift make it fairly easy.
OK, now we're done! I made the steering drag link adjustment to re-center the steering wheel while you weren't looking. (In my driveway after driving it home, if you must know.)
If you thought the rear installation looked easier than the front, you're right. Now that I've done it, this isn't ridiculously difficult with the right tools. Thing is, the "right tools" is no small list. And our Rotary Lift certainly helped. I'm sure it could be done without such a lift, but it wouldn't be easy.
Dan Edmunds, Director of Vehicle Testing