I’ve heard stories that the fuel tank and battery cause the “JK lean”. I don’t buy it. If that’s the case then every Jeep out there will lean to the right and the dealers would have to explain to every customer why a multi billion dollar company can’t design a vehicle that sits level. Also, many people on other threads have mentioned weights per wheel and it’s not that far different to cause a drastic lean.

My jku leans to the passenger side by about an inch. I’ve ignored it for the last several months and now I have time to dig into it, and all the other bigger problems (upgrades) have been taken care of.

Some history, I got the Jeep a couple years ago and it came with the factory 3” lift (teraflex). When I got the Jeep it didn’t lean, it sat level. After beating the Jeep up on the trails I got a death wobble and replaced all control arms, tie rod, drag link, and both track bars. After replacing those components I noticed the lean. Measuring from the ground to the frame, the right side leans by just a smidge over an inch at both the front and rear.

Possible causes...
springs can be worn on the right side but I doubt it. I’ve read too many threads where people swap the springs and the lean still exists.

Fuel tank and battery weighing down the right side... I don’t think so, see above. Plus, the lean is the same (+/- a hair) if I have an empty tank of gas or a full tank.

axles not centered properly under the vehicle, maybe. Tomorrow I’ll park on level ground and measure the centerline of both the axles and frame to verify they’re still centered. I did verify with the alignment tech when I got my last alignment done and both axles were within a tenth of an inch from center.

Track bars have a bind in them? I’ve read some people loosen the track bar hardware, rock the Jeep, and tighten the hardware and this fixes it.

Throw a spacer on the right side springs, I cannot bring myself to do this. This seems like a workaround and is not fixing the issue but just masking it.

If anyone has other possible causes for this lemme know and I’ll check that too.

 

Could just plain be a weak spring on the right - metallurgy and all that stuff.

 

I'm curious as well, though I think my results are skewed as I'm running two batteries on that side. The other things I've considered are the spare tire (open the gate and you'll really see the corner lean- it can be helpful for reconnecting sway bar links) and the point that when you get on the gas, that's the direction everything torques. Every day, every single time you get on the gas, it's compressing the right rear and with the weight shift to the back, you won't see it on the front. Just thoughts, no science. If I had a more level garage floor I'd pull numbers to consider.

 

I don’t have a spare tire mounted and I’m not using sway bars. I’ll swap the springs just to rule out a weak right side spring.

 

Interesting observation while looking around and playing with things. when the steering wheel is centered, the Jeep leans to the right about an inch or so. If I turn full left, the Jeep leans a LOT more, about another inch. But when I turn full right, the Jeep sits level.

This makes a little more sense now on why this issue showed up suddenly after I replaced my control arms. This is related to the front end alignment I think.

 

Back to the drawing board, the front axle tilts slightly when turning left or right. So, when turning right, the right side of the axle tilts up a bit and raises the right side of the Jeep. When turning left, the left side of the axle raises up a bit... and you guessed it... the left side of the Jeep raises up. Of course, since the right side of the axle raises up when turning to the right, the Jeep levels out.

I did try to see if it was track bar related by measuring axle movement when turning left and right, the axle didn’t budge a bit, not even a smidge. I thought that since the Jeep isn’t moving and the large wheels turning, the axle may want to shift a little and thus put a tad bit more weight on one side of the axle causing a lean.

Im totally shooting in the dark just looking for anything that doesn’t make sense till Monday when I can dig into it a bit more with wrenches.

 

You measured the rear axle for being centered too?

 

I didn’t measure it, the alignment sheet from February says the rear axle is 0.1” to the right of center while the front axle is 0.1” left of center. Both are very close and in spec according to their printout.

 

Long story short....I cheat my rear axle just a touch to the driver's side. Thinking back, that is generally about the time I started noticing a pretty good lean which had not been apparent the previous 6 years. Swapped coils from side to side, tried rotating coil on passenger side....none of it mattered. I popped in 3/4" spacer on passenger side F&R and I just don't really worry bout it.....in the same manner I don't worry about the rake I have either (jeep level is always changing with top on or off, towing trailer or whatnot). I've never had an issue running this way so I just haven't let it bother me much. Kinda wonder now if I had it dead nuts centered again if it would eliminate some of the lean.

 

Why intentionally have the rear axle to the driver side? The only reason my rear axle isn’t completely centered is because when I had my alignment done, I had a stock rear drive shaft and hadn’t moved my evap canister yet. Otherwise, I’d have my rear axle centered. As for the front axle, I don’t remember why we put it slightly offset to the left, but we did it for a reason... it made sense at the time and I wish I could remember why.