Mopar LCA swap

cbrenthus

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Rubicon stock height can completely be done with the vehicle on the ground, the others I’m not sure of. I went out for a hundred mile drive today on a mix of roads and it was a much improved experience, everyone should be putting these on, I see no down side.
Good point, but there shouldn't be a need to put these on a Sport or Sahara unless they have installed a Rubicon suspension. The problem is that FCA didn't use the proper control arms for the Rubicons to correct the caster fr the height. If you put these on a stock non-Rubi, you're going to have 8 degrees of caster!





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Keycub

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So today I finally swap my stock LCA with Mopar lift LCA, my JL is currently at stock height, but I hope that slightly longer LCA can give me a bit more caster. Also, it is Mopar so the dealer can't tell I swapped unless they look at it under a microscope.

As you can see in the picture, Mopar lift LCA is slightly longer than the stock LCA (measured by about 1/4 inch). In case you are interested in doing this mod, the part number for Mopar lift LCA is 68322798AA. If you want to use a new set of bolts and nuts, they are 6512085AA (bolt, M16-1.5x104mm) and 6104720AA (nut). The torque specs are 190 ft-lb. The 103 and 125 ft-lbs floating around the internet are from the old JK smaller bolt and nut specs, JL has a larger bolt so the torque should be much higher.

Some tips for your installation:

(1) Tools, tools, tools! Breaking free LCA requires a 21 mm deep socket and 24 mm wrench, since the space is really limited under the car, you need to have an impact wrench that can deliver good torque.

(2) The new LCA will be longer, so you need to jack up the frame slightly (shown in another picture, please ignore the crappy bottle jack setup, I am just too lazy to pull my 3-ton). This will move axle forward and help align the holes.. Once you push one side in, the other side should be easy since the axle is already moved.

(3) I put a tiny bit of anti-seize in the LCA mount, does not hurt to have a little bit.

20190125_125501.jpg


20190125_130524.jpg


Update: not sure if it is placebo, but my Rubicon now tracks super straight, I can keep it straight at 70 mph with one finger. I will do an alignment next week to see how much caster I gain but it is definitely a much improvement.
Do you know the length of the updated LCA?
 

laniercruzer

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Good point, but there shouldn't be a need to put these on a Sport or Sahara unless they have installed a Rubicon suspension. The problem is that FCA didn't use the proper control arms for the Rubicons to correct the caster fr the height. If you put these on a stock non-Rubi, you're going to have 8 degrees of caster!
That’s true, so Rubicon wise, these are a no brainer for $60...mine is driving so, so much better. I have zero complaints now, Falcon 2.2 Stabilizer goes on next week just for piece of mind, the roads down here are crap.

Some part of me also suspects the stiffness of these is also helping somehow, they are seriously quite a bit heavier than the stock parts, I should have weighed both.
 

omi205

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Just got my Mopar Lift LCA's today and compared them to the stock LCAs that come on all the JL wranglers. Just from looks, you cannot tell much difference besides the part number that is stamped on them. But when you pick them up...oh boy. The Lift LCAs are muchhhhhhh heavier.
 

DennyCrane

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Good point, but there shouldn't be a need to put these on a Sport or Sahara unless they have installed a Rubicon suspension. The problem is that FCA didn't use the proper control arms for the Rubicons to correct the caster fr the height. If you put these on a stock non-Rubi, you're going to have 8 degrees of caster!
But what if someone puts on a 2.0 inch spacer lift? Isn't that the same thing?
 

Keycub

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This is by far the most interesting thread on the JL steering problems. My 2020 JLUR came with 68250242AB lower arms. I just ordered a set of the 68322798AA arms from Allmoparparts. Curious to measure the old ones to the new ones and see what is actually on the truck stock. Caster angle seems to be around 6 degrees stock, measured with an Iphone. I have an angle finder on the way as well.
How did the measure out? Which were longer?
 

Ribs33

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I'd like to know? Thinking of ordering these also
The Mopar extended lower control arms (68322798AA) are about 1/4" longer than the stock (68250242AB).

My caster was 4.6 degrees with the stock and is 6.1 with the 1/4" extended arms.
 

blnewt

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Here's my quick write-up of the swap, took me about an hour since I didn't use my impact.
IMO Ramps are best for getting this swapped out, makes it much easier to have decent range for your breaker bar. My ghetto ramps (1 sheet of stacked OSB makes 2 ramps, much stronger than pressed steel ramps) lift about 6" which is fine for this project. And they stack well for a small storage footprint.
IMG_0284.JPG

IMG_0285.JPG

IMG_0278.JPG


LCAs can be bought here, need to order 2 https://www.allmoparparts.com/sku/68322798aa.html
One thing you notice is the new LCAs have a different bushing design, the older ones had an outer rubber seal, the new ones have the seal inward. Also like others have mentioned, the new LCAs are heavier, so they must have seen a need for a more rigid bar.
IMG_0281.JPG



Only tools I used was 13/16" socket, 15/16" box end wrench, 15mm socket, torque wrench, breaker bar, and a cheat pipe (the handle for my floor jack). FWIW the SAE size sockets are a perfect fit on the bolts/nuts, the 21mm and 24mm that have been used by others ARE NOT a tight fit, and there's been at least one install that I read that had stripped the bolt head, so use those 13/16" sockets especially!

IMG_0282.JPG


Also a spray of PB blast a day before will help to break the nuts. I only had to use the cheat pipe on my rear passenger side bolt, all others broke w/ just the breaker bar.

Remove brake line bracket w/ 15mm socket.

Not sure if the angled load from the ramps shifted things a bit, but I didn't have to move or pry on anything to get the new longer LCAs installed, the bolt holes lined right up. Removing the bolts from the original LCAs did require just unscrewing them to slowly get them out as they were binding a bit.

I used my 150 ft. lb torque wrench maxed out, then used my breaker bar for another 90 degrees of final torque to tighten the four bolts.

Caster looks to be in the 6 degree range, and steers just as it did prior to my Rubicon spring swap.
IMG_0288.JPG


Reinstall brake bracket, and drive it like you stole it!
 
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jmcdtucson

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and a cheat pipe (the handle for my floor jack).
Dang, why didn't I think of that.

the bolt holes lined right up
Don't want to hear it. This never happens for me. Had to finagle, tug, use another jack to move the axle, etc. to get mine to line up.
 

TopsOff

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Finished installing the LCA's on my 2020 JLUS. Install was straightforward. Glad I did this relatively early at 4000 miles and before the northeast salt machine / corrosion made it even harder. As pointed out on page 1 - the right tools are your friend. I drove the front of Jeep up onto 6" ramps to give myself some more room. My air impact was no use as it's relatively weak, so I broke the bolts free the old fashioned way: breaker bar with pipe extension as needed. Working underneath a stock height JLUS trying to break these free is challenging - as the force needed to pull or push tended to just slide me around on the floor. I had to get creative with bracing myself underneath the Jeep - wish I had a picture of the contortions I had to use at different points.

Here are some thoughts:
  • My JLUS is stock height - and I did this to add caster to help with the wander. I have the AE box and chose the best vehicle out of the Jeeps I test drove - even gave up on the Altitude I really wanted - but this Sport S still needed some improvement.
  • Pre-swap caster measured at about 4.8 on the digital gauge. Post-swap I'm seeing about 6.6. More on this later. There's too many variables in the measurements to say they are exact.
  • The rumor that FCA started putting the longer arms on production 2019's or 2020's isn't supported by my Jeep. My 2020 JLUS had the 68250242AB front LCA's. Build date was August 2019.
  • The 68322798AA's are indeed longer and have a different bushing seal design.





  • Standard size deep socket 13/16" fit tighter than 21mm as reported earlier. With the torques involved here I wouldn't use metric. I held the nuts with a 15/16" wrench. The brake line brackets are low torque and I used a 15mm socket.
  • I broke everything free, then swapped one LCA at a time. I recommend to anyone doing this - do the same. Loosen everything before you do the swap. This way if you swap one side and can't break the other side free....you don't have to go too far backwards!




  • I used a drift punch and small hammer to lightly tap the bolts out vs using the impact or socket to spin them out.
  • I had zero issues with re-assembly. No ratchet straps or floor jack required to coax alignment, I loosely connected the rear end of LCA first, then lifted the forward end into place. The bolt slid right in. It was at this point I took the LCA back out and compared it carefully to the old one and took the above photos. I doubted the difference in length because it was so easy.
  • I tightened the rear ends of LCAs with my impact and the front ends with hand tools. (My old craftsman air impact would not fit outboard of the LCA with a deep socket attached.)
  • I torqued all 4 bolts with weight on the front axle (on ramps) which is important for correct indexing of the bushings - although technically this is still incorrect with the front end up on a ramp and the rear end on the floor. I will probably be revisiting this next time I'm under the Jeep by raising the rear end to level the Jeep. I recommend anyone doing this should level their jeep with both axles bearing full weight before torquing down the 4 LCA bolts to final values.
  • FCA spec for torque is not 190 ft lbs (per Jay). 190 is a Quadratec number quoted from lift instructions by the sounds of it. These are 10.9 grade bolts and don't appear to be torque to yield. (If they were it would be visually apparent and I'd have replaced them) They are, however, torque to angle - and that's probably for good reason. Someone can ask Quadratec but I suspect they came up with 190 to simplify this for folks not familiar with torque to angle specs. I torqued my first one down to the spec'ed 103 ft lbs and then tightened 50 degrees (ballpark) further. The +50 concluded at about 160-170 ft lbs on that one bolt. Again - lots of variables here with friction that will vary between bolts and vehicles and conditions. Full disclosure - I did tighten to 190ft lbs on all 4. (finished before overthinking all this) This ended up being about 103 plus 100 degrees, maybe a little more. I will be re-torquing to the 103 + 50 when I level the Jeep and repeat final fastener tightening. I just think 190 is unnecessary and not to spec. The idea is to pinch the serrated metal bushing so it can't spin within the LCA frame mounts. I don't think 190 is needed for this, and 160 isn't going to loosen on us.


The above photo is how I crudely torque to angle. 50 is pretty easy being so close to 45.

To reiterate caster measurement. If you put a digital angle gauge on the spot highlighted earlier in this thread adjacent the pumpkin - a measurement of 0 means you have 6 degrees of caster. I saw 1.2 to 1.3 in my garage pre-swap. Before measurement I calibrated the gauge to zero on the floor under axle (which isn't dead nuts accurate as thats just one spot on the slab vs calibrating it on a long straight edge oriented fore-aft with the Jeep). This isn't a moon launch - I just wanted a ballpark. Post swap I saw .6 in the other direction for a total change of about 1.8 degrees. My fuzzy math: With 1.2 degrees fwd tilt towards radiator - I had (6 minus 1.2 = 4.8). Post swap I had .6 degrees rear tilt towards tailgate - meaning I had (1.2+.6=1.8) (4.8+1.8=6.6) I doubt it's that high in reality if I took it to a good shop that knows how to use their equipment. But that means paying by the hour, and this isn't my track car.

You can put a digital magnetic angle gauge on bottom of the "C" but that is not level laterally. It's close - but not as close as doing it as photographed here.



The results.......I'm happy. It improved the wander. It does NOT improve the dead spot, which on my JLUS isn't really a dead spot. It's just a null zone where 'stuff doesn't happen quickly'. I believe this is just part of the programming related to the electric PS. It's like running 'exponential' on an RC car or aircraft. If I throw my wheel back and forth from 1" either side of center at 70 mph - not much happens with the Jeep. But....if I hold that 1" deflection either side - she turns. If I hold 1/2" - she turns. With a dead spot nothing would happen. Mine just felt - especially between 35-45mph - like the wheel didn't like returning to center. This forced me to not only STOP the drift - but also remove the correction afterwards. That's why I feel like the Jeep 'wanders'. This isn't natural and isn't required in any other vehicle I've driven. The additional caster so far really feels good - but I'm only 20 miles in. I drive her to work tomorrow 120 miles R/T on the highway. I'll report back after that.
 

RubiRob

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[QUOTE="TopsOff, post: 963414, member: 41352”]

FCA spec for torque is not 190 ft lbs (per Jay). 190 is a Quadratec number quoted from lift instructions by the sounds of it. These are 10.9 grade bolts and don't appear to be torque to yield. (If they were it would be visually apparent and I'd have replaced them) They are, however, torque to angle - and that's probably for good reason. Someone can ask Quadratec but I suspect they came up with 190 to simplify this for folks not familiar with torque to angle specs.
[/QUOTE]

fca torque spec is 190. That’s per the official instructions on the mopar lift kit
 

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