LX 570 AHC Sanity Check (1 Viewer)

[txclimber]

Hey folks. Just finished up with a flush/bleed of the AHC system on my 2010 LX570. No previous issues, but it's over 100,000 miles and I didn't have any documentation that it had been done before. Seems like everything went as it should. My system continues to work as expected, but of course since I've been messing with it I'm looking more carefully than I have previously.

Now I notice that when set in the "N" position the passenger side seems to ride a half inch or so higher than the drivers side. I can't say for certain that it was or wasn't like this before the flush. I'd appreciate it if some of my fellow LX570 owners could step outside and take a look at theirs. It's most noticeable in the rear. Is the gap between the top of the tire and the fender the same on both the drivers and passenger side? Thanks!

 

[eatSleepWoof]

When comparing side to side heights, ensure you are on 100% level ground, otherwise the LX will self level and you’ll see a height difference.

 

[k33fr]

Also, pretty common for LR corner to sag a bit. There are threads here that explain a spring swap to fix it.

 

[lx200inAR]

Also, with all the variables involved, nearly impossible for it to matter what someone elses truck is doing. I wouldn’t be concerned about 1/2” even if it was there. And as said before. Not uncommon for passenger side to run a little high. If you didn’t touch your sensors, good chance you are just looking for problems. (I certainly have this affliction as well).

 

[txclimber]

Thanks. I feel like I'm looking for problems too. BTW, yes I'm on a perfectly level shop floor. And I'm familiar with the drivers side lean from previous 4Runners, but two things seem to be at odds with each other. If the AHC system is smart enough to level itself out if the ground is uneven, how is it too simple to level the vehicle out if the ground is level? In other words, the drivers side lean shouldn't be a thing with an AHC equipped vehicle, regardless of weight distribution without a spring change. But, alas, I read that it is.

 

[AnyMal]

Certified insane person here and avid problem finder.
(And problem causer)



First off you’re not crazy. They all lean straight out of factory. Second AHC is a gift and a curse. Third, mr Toyota makes a lot of bad choices.

If you wanna fix this the right way go read my post in the AHC threads.

 

[lx200inAR]

Thanks. I feel like I'm looking for problems too. BTW, yes I'm on a perfectly level shop floor. And I'm familiar with the drivers side lean from previous 4Runners, but two things seem to be at odds with each other. If the AHC system is smart enough to level itself out if the ground is uneven, how is it too simple to level the vehicle out if the ground is level? In other words, the drivers side lean shouldn't be a thing with an AHC equipped vehicle, regardless of weight distribution without a spring change. But, alas, I read that it is.

The quick answer is that there are at least 2 other functions of AHC that can affect height, outside of the sensors height matching function. There isn't a lot in the manual about when all these function, or what the targets the truck sets for meeting height sensor requirements are. So to some degree, getting perfectly level is a dance between the state of the springs (age or preload) on the truck and the relationship between the pressures in the AHC system and the sprung weight at each corner of the truck. And we know that the right rear spring is longer than the left rear spring already.

Edited typo about spring placement

 

[AnyMal]

The quick answer is that there are at least 2 other functions of AHC that can affect height, outside of the sensors height matching function. There isn't a lot in the manual about when all these function, or what the targets the truck sets for meeting height sensor requirements are. So to some degree, getting perfectly level is a dance between the state of the springs (age or preload) on the truck and the relationship between the pressures in the AHC system and the sprung weight at each corner of the truck. And we know that the Left rear spring is longer than the right rear spring already.

Rear right is the longer one, and is the cause of most leans i think. Anything LHD will lean to driver or its incorrectly shock loaded/adjusted. The reason being gas tank which is kind of dumb as its barely 140 lbs totally full which we all know it never is.

What i would love to figure out now, is what provisions toyota made in the damping rates (if any) for the imbalance, and if the pan-hard angle etc should be adjusted for matching springs. I do know that our shocks are not mounted transverse to the axle. I hope someone with more knowledge than i can explain why they chose to do that.

I will say though, my s*** now eats speed bumps pretty much flat with little drama (even lifted), with no more uneven bucking of the rear axle. Just the expected front/rear bounce. So i don't think there is any custom work at all to be honest. Im happier than ive ever been with it, and ive had moments thinking i would ditch the LX for an LC.