LX570 AHC “Basics” - Added as sticky thread for AHC Issues (5 Viewers)

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radman said:
Has anyone ever noticed the AHC pump randomly running during extremely cold temperatures?

Currently at 9,000’ and 20 degrees Fahrenheit. I ran out to pick up the gear we had left out, and I noticed an electronic humming sound. Didn’t think much of it until I noticed it was coming from the rig. Rear passenger side.
I was too cold to investigate, so I started her up, no errors or dash lights, and then shut her down. No more humming. 🤷🏻‍♂️
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In extreme cold? 20F? For us that’s shorts and flip flops if it’s sunny, shorts and extra tuffs if the weather is rough :)

Most years my LX spends more time outside below freezing then above freezing. ive never noticed anything odd from the AHC pump even down into the -30’s F (thats negative 30’s) Could your truck have been on un level ground? Like others I’d say it not related to the temperature, 20F is fairly mild, don’t even need a block heater or battery blanket in those temps.
 
radman said:
That makes a lot more sense, thanks.
had been stopped for ~5 hours. Is this something that always happens or only cold weather?
Click to expand...

i believe it does it after driving a certain time or distance and about 4 hours after vehicle has been stopped. That’s why if you have an evap leak (gas cap) the error can come back after you park
 
I did mine today.
I followed process using H mode (not factory N mode). I think factory tells you to use N to avoid running tank dry.
I didn't bother emptying tank either. Fluid in it actually looked pink. It was flushed 50k miles ago, when one of the lines raptured due to corrosion.
I put the car in High mode and bled it down. I returned to N then added fluid then brought to H and bled again. I think 4 quarts is a good flush. I did 4.5 so will do a bit to use up all 5 that I bought.

Other notes:
This is a solid 2-3 hour job. Easy but takes time. I have decent mechanical experience and good tool selection, but I did this in a driveway. Good funnel with a long neck is very helpful here. I bought one at autozone that you can fill with fluid, connect to the filler and then twist to let fluid down. Pretty nifty but I still made a mess.

Make sure to set level at or below max in N when done. Otherwise tank will get too full and might spray fluid through breathers.

I'm glad I did the flush after 50k. While fluid in the tank looked pink. It was pretty dark in all 4 corners and had a LOT of air in one corner. That's the same that had issue 4 years ago so the shop may have not flushed it properly or they didn't bleed after they fixed their mess up. I wish I replaced the lines myself.

One tip: if you bleeder is hard to turn, especially on the rear shocks with tight access, use 10mm 1/4 socket to break it lose. I used flared wrench with tilting end and stubby wrench. Front bleeder are easy, rear bleeders suck getting to. I didn't have by brake bottles handy so I bought 1/4 OD clear tubing (which was very tight) at HD and used a used DD iced coffee cup.

If you bleed slow, the car goes down slow, I thought it was going to drop down, but it goes down nice and smooth and I could regulate it with the bleeder valve.
 
for Filling the reservoir I had a similar contraption of a tube with a twist valve. I cant remember now if it came with a funnel, as I didn’t know what was going to work best and bought 3 or 4 options. What I did was unscrew the tube from the funnel and attach it directly to the bottle of AHC fluid. then I used the twist valve to regulate flow. The filler tube of the tank will not allow full flow, it will end up gushing out if you go full speed. There is just barely enough room in the wheel well to let all the fluid out of the AHC bottle.
 
Didn't see anywhere here:
Do ride height changes effect alignment? I have seen people adjusting the height sensor to raise or lower the car a bit in the N setting.
On most cars, changing ride height will have effect on camber and as a result on toe. On SUVs suspension geometry might be different and designed for rider height changes.
It doesn't look that toe or camber changes as it looks like everything simply raises up or down. But I wonder if that's really true or not.
I would prefer lowering the car in N a tiny bit to be more level with my trailer and just have lower center of gravity in general and cruising on highways. The car is tall enough as is.
Anybody got info or link to this topic already discussed?
 
RatherBeRacing said:
Didn't see anywhere here:
Do ride height changes effect alignment? I have seen people adjusting the height sensor to raise or lower the car a bit in the N setting.
On most cars, changing ride height will have effect on camber and as a result on toe. On SUVs suspension geometry might be different and designed for rider height changes.
It doesn't look that toe or camber changes as it looks like everything simply raises up or down. But I wonder if that's really true or not.
I would prefer lowering the car in N a tiny bit to be more level with my trailer and just have lower center of gravity in general and cruising on highways. The car is tall enough as is.
Anybody got info or link to this topic already discussed?
Click to expand...
You need to get an alignment after LX570 AHC height modifications (lift it!) - https://forum.ih8mud.com/threads/lx570-ahc-height-modifications-lift-it.971211/post-11516026
 
RatherBeRacing said:
Didn't see anywhere here:
Do ride height changes effect alignment? I have seen people adjusting the height sensor to raise or lower the car a bit in the N setting.
On most cars, changing ride height will have effect on camber and as a result on toe. On SUVs suspension geometry might be different and designed for rider height changes.
It doesn't look that toe or camber changes as it looks like everything simply raises up or down. But I wonder if that's really true or not.
I would prefer lowering the car in N a tiny bit to be more level with my trailer and just have lower center of gravity in general and cruising on highways. The car is tall enough as is.
Anybody got info or link to this topic already discussed?
Click to expand...

To add some more detail. While a mild 1" lift won't affect alignment appreciably, it will be enough that you'll want to get an alignment anyways to maximize tire life, but also performance.

Few things:
- Toe will tend towards toe in with lift (positive toe), with this being the largest factor for tire wear
- Caster will be reduced, towards low end of spec making steering feel a bit looser with less self centering, and perhaps more steering corrections
- Camber will go positive (bow legged), reducing turn in sharpness, cornering traction, and allowing taller profiles tires especially to roll over onto the sidewall more easily

Alignment shops may be lazy and only fix toe, as the other parameters may still technically be in spec. Ideally, you'll want them to dial in more caster and bring just a bit of negative camber to help tall profile tires handle better.

With AHC in particular, because of it's ability to run in high mode, if caster and camber are not addressed, results in further loss of caster and really bad positive camber in high mode, for not so great handling off-road.
 
A while back when I bought LX, I went to Toyota dealer and asked if they can add caster so the car wonders less on the highway...the SA (who claimed to set race cars in the past) was so confused. I hate going to dealers for anything. Caster is a bit trickier to measure, which I haven't done.
 
RatherBeRacing said:
A while back when I bought LX, I went to Toyota dealer and asked if they can add caster so the car wonders less on the highway...the SA (who claimed to set race cars in the past) was so confused. I hate going to dealers for anything. Caster is a bit trickier to measure, which I haven't done.
Click to expand...

LOL, sums up my experience too, at Lexus. First alignment pass, they only bothered with toe. Didn't touch caster or camber, even though caster was just outside of spec. From your screen name, I likewise have a racing background and I'm particular to alignment and handling feel.

Talked to 2x service advisors stating it drove looser than my preference and tires roll over on cornering (in spec but with positive camber). They had no clue other than "test drive showed it drove straight."

Finally got to talking with the shop supervisor who was happy to put numbers where I wanted. But he could only relate once I started talking about towing as he tows too. How marginal alignment can turn poor when towing as it picks up the nose just enough to further change alignment. He tried to give me hints to improve my towing setup recommending I use a WD hitch (I already do), but relented once he was convinced I was setup well otherwise. Guess that's the bar of customers he's generally dealing so I was willing to go along. Only took 3 days (thank goodness for a complimentary loaner) to talk to the right people. They were always amicable being Lexus, but it did take some effort and discussion to get the alignment I wanted.

This isn't rocket science, but maybe better to go to a specialty 4x4 shop.
 
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Anybody has FSM for alignment?

The rear is solid axle with no adjustments it seems.

I see where front camber adjusts, but I'm not sure if you have to keep both eccentrics in the same position of if you can dial in caster by independently adjusting them.

Toe is the same as all cars and aligning this truck must be so easy everything is right there.
 
TeCKis300 said:
From your screen name, I likewise have a racing background and I'm particular to alignment and handling feel.
Click to expand...
Yea a few of us split string set and camber gauge and we align our own track cars (Porsche cayman/boxster, 911s, bmws). The hardest part is the set up of the strings. Adjustment is fairly easy and toe is really what matters the most.
 
My 2011 LX has about 135k miles on it currently. I did a full AHC fluid change approximately approximately 25k miles ago. Currently have Falken Wildpeak AT3's in 275/65/20's on the stock rims with about 30k miles on them and doing the 5 tire rotation has them still looking all wearing evenly and in great shape.

My ride quality has become noticeably worse and feels like the damping and rebound has taken a hit, which shouldn't be too surprising given that if this was a traditional suspension , it would be getting pretty tired by this point anyways. I don't see any leaks from any of the struts and from my understanding both here on the 200 forums and the guys on the 100 series, it looks like the globes are a pretty prime suspect. I've given thought to ditching the AHC system but as has been discussed, it's just so versatile. I think even if I replaced all 4 globes AND the struts, it would still be less than a descent Land Cruiser suspension.

How many people have replaced their globes for the 200 series and did you use OEM? I found this on ebay that the 100 series folks seem to be pleased with: Lexus LX470-LX570 y1998-2017 = SPORTS KIT = AHC Suspension Accumulator Spheres | eBay - https://www.ebay.com/itm/Lexus-LX470-LX570-y1998-2017-SPORTS-KIT-AHC-Suspension-Accumulator-Spheres/124360076075?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20131231084308%26meid%3D56d12b131fff4ab899d5d6e29110a4c6%26pid%3D100010%26rk%3D2%26rkt%3D12%26sd%3D124360076085%26itm%3D124360076075%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganicWithAblationExplorer&_trksid=p2047675.c100010.m2109
 
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