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Mopar LCA swap

Keycub

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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.
Jeep Wrangler JL Mopar LCA swap {filename}


Jeep Wrangler JL Mopar LCA swap {filename}

Jeep Wrangler JL Mopar LCA swap {filename}


  • 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!
Jeep Wrangler JL Mopar LCA swap {filename}

Jeep Wrangler JL Mopar LCA swap {filename}

Jeep Wrangler JL Mopar LCA swap {filename}


  • 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.
Jeep Wrangler JL Mopar LCA swap {filename}


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.

Jeep Wrangler JL Mopar LCA swap {filename}


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.
Cast
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.
Jeep Wrangler JL Mopar LCA swap {filename}


Jeep Wrangler JL Mopar LCA swap {filename}

Jeep Wrangler JL Mopar LCA swap {filename}


  • 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!
Jeep Wrangler JL Mopar LCA swap {filename}

Jeep Wrangler JL Mopar LCA swap {filename}

Jeep Wrangler JL Mopar LCA swap {filename}


  • 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.
Jeep Wrangler JL Mopar LCA swap {filename}


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.

Jeep Wrangler JL Mopar LCA swap {filename}


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.
caster sounds about right. I ended up with 6.3 with a dynatrac 2 inch lift and Mopar lift LCA’s.
 

blnewt

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Nice write up TopsOff (can't see your pics though :( )
I'm a bit surprised your Caster was that low prior to the LCA swap, mine was much closer to 6, maybe mine being a 2 dr. played a role in that???

Did you use any rust breaker spray prior to the job?
 

jmcdtucson

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So is Jay wrong with the 103+50? Where did that come from?
103+50 is for the stock LCA's.
190 is for the Mopar lift LCA's (the ones you installed).

It's the same bolt so I don't understand the different recommendations.

At least that's what I've come up with from reading about 1000 posts on the subject :)

Nice writeup by the way.
 

word302

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103+50 is for the stock LCA's.
190 is for the Mopar lift LCA's (the ones you installed).

It's the same bolt so I don't understand the different recommendations.

At least that's what I've come up with from reading about 1000 posts on the subject :)

Nice writeup by the way.
It's because they are both going to net roughly the same amount of torque.
 

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AnnDee4444

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103+50 is for the stock LCA's.
190 is for the Mopar lift LCA's (the ones you installed).

It's the same bolt so I don't understand the different recommendations.

At least that's what I've come up with from reading about 1000 posts on the subject :)

Nice writeup by the way.
The 103+50 degrees is the "turn of the nut" method. As I understand it, torquing a bolt isn't as effective at measuring the tensile load as the turn of nut method, because the friction on the threads varies. A crusty old bolt will hit 190 lb-ft of torque far sooner than a new properly lubed bolt. The turn of nut method attempts to take this variable out, by targeting a specific position of the nut rather than torque value. The turn of nut specs you listed are specific to the OEM hardware, as a different thread pitch could mean a different specification.
 

Onward4x4

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I am not sure why FCA is not pushing this easy and cheap fix on all Rubicons, but again they are replacing the whole rear glass because of a small defroster detachment, so there you go.

Rubicon suspension is about 1.5 inches higher than Sahara and Sport, but all three use the same length LCA. Therefore Rubicon has a lower positive caster (typically 4~4.5) while Sahara and Sport have 5~5.5. The low caster affected Rubicon's ability to track straight, return to center, and make other steering components more vulnerable. It gets even worse when installing Mopar lift as they give almost 3", and some forum members reported their casters after lift was in the lower 3.

For stock Rubicon, one cheap fix is to use Mopar 2" lift's LCA since they are slightly longer. It is perfect since too much caster can also cause steering issues. Mopar 2" lift LCAs are about $60 for a pair. This is much cheaper than even a caster bolt or correction bracket. Best of all, the old and new LCA look the same so warranty is preserved with even the pickiest dealer.

For lifted Rubicon, an adjustable LCA (Teraflex, etc.) should be used to correct caster.
Awesome information. Now, do you think the same issue you referred to for a Rubi would also exist in a Sahara with Rubi suspension swap? My Sahara tracking is weird... at times, it is supper straight and good and at times it pulls heavily to the left... If it doesn't go straight, it always pulls to the left never right... So I am perplexed.
 

blnewt

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Awesome information. Now, do you think the same issue you referred to for a Rubi would also exist in a Sahara with Rubi suspension swap? My Sahara tracking is weird... at times, it is supper straight and good and at times it pulls heavily to the left... If it doesn't go straight, it always pulls to the left never right... So I am perplexed.
Low caster can cause what you're dealing with, more prone to wander off the center, not sure why yours is always prone to wander left, but the fact that it isn't staying locked at center indicates low caster as the primary culprit, especially since you raised your JL.
Caster is roughly decreased by a degree for every inch you lift, so a Rubi swap will lift you in the 1.5 to 1.75" range, decreasing your caster by that 1.5 to 1.75 degree. My JL 2 door sport w/ Rubi 4dr springs wasn't tracking nearly as well prior to the longer Mopar LCAs, having that caster in the 6 degree range (which you will be w/ the Longer LCAs) is the sweet spot for the JL caster. My steering was as perfect as you can get AFAIK when it was stock (w/ the newest Mopar steering damper recall), and getting that caster back up to that range, I was happy again. You will be much happier w/ this upgrade.
 

word302

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Awesome information. Now, do you think the same issue you referred to for a Rubi would also exist in a Sahara with Rubi suspension swap? My Sahara tracking is weird... at times, it is supper straight and good and at times it pulls heavily to the left... If it doesn't go straight, it always pulls to the left never right... So I am perplexed.
Your tires, pressure, and toe could all be factors as well.
 

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TopsOff

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Follow-up report:

The additional caster changes the wander for the better IMHO, but doesn't eliminate it. Steering forces are higher, especially at the higher speeds. She self centers better out of the slow speed corners - like a 90 degree right turn off a stop sign. With the lower caster I'd have to help it center up in those situations. On the highway she's a bit more sensitive to road crown. I'd say overall she's got a snappier feel. All consistent with what to expect at higher caster settings - but this isn't 'the fix'.
 

blnewt

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All consistent with what to expect at higher caster settings - but this isn't 'the fix'.
Not "the fix" for many steering woes, but at least in my case it restored my fine steering back to being fine again after the Rubicon suspension swap. And I would highly recommend this "fix" to anyone that has a Rubicon (with no plans to further lift it) or Sport/Sahara owners that swap to Rubicon suspension or lift 1.5 to 2".
 

wv18jl

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Great post
Thanks for all who took the time to respond
Did mine today
Went as previously described
Did buy a 3/4" ThunderGun to save my old ass the effort
I always get frustrated by people who say "my seat of the pants ..."
But ...
Does feel noticeably different and more ... solid
No measurable difference, just feels better.
 

Jmc711

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I might be crazy but the site says the longer arms won't fit my 2020 JL? Any idea why? Is it because it's designed for lift kits?
Jeep Wrangler JL Mopar LCA swap {filename}
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