AHC woes

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If you have 215k mi on the original steering rack, those bushings (and the rack itself) could be a potential source of your mystery noise.
Rack & pinion done around 190k with control arms. I’ll make a thread later got my truck and I’ll add the whole history.
 
So, not the torsion bars? Apparently it’s the driver side that is cranked up a lot, as it was sagging down. The noise is coming from the passenger side, which isn’t cranked as much. I have no idea what the pressures look like.

ETA: Again, the torsion bars were only cranked to correct ride height back to level, not to jack the car up above normal right height in any way.
 
So, not the torsion bars? Apparently it’s the driver side that is cranked up a lot, as it was sagging down. The noise is coming from the passenger side, which isn’t cranked as much. I have no idea what the pressures look like.

ETA: Again, the torsion bars were only cranked to correct ride height back to level, not to jack the car up above normal right height in any way.
Torsion bars don’t have much affect on the ride height, but rather cross leveling. Regardless, they have constant load on them so I don’t think they could be making the noise.
 
Torsion bars don’t have much affect on the ride height, but rather cross leveling. Regardless, they have constant load on them so I don’t think they could be making the noise.
Was thinking more along the lines of the pressure from the torsion bars being cranked causing the noise in something else, like someone said about the AHC pressures, rather than the torsion bars themselves being noisy.

I admit I know close to nothing about torsion bars. But that’s what we cranked to level the car. Little bit one one side, little more on the other, back and forth until the heights were even on the front. Before I had a saggy drivers side.
 
Torsion bars don’t have much affect on the ride height, but rather cross leveling. Regardless, they have constant load on them so I don’t think they could be making the noise.
Was thinking more along the lines of the pressure from the torsion bars being cranked causing the noise in something else, like someone said about the AHC pressures, rather than the torsion bars themselves being noisy.

I admit I know close to nothing about torsion bars. But that’s what we cranked to level the car. Little bit one one side, little more on the other, back and forth until the heights were even on the front. Before I had a saggy drivers side.
 
Was thinking more along the lines of the pressure from the torsion bars being cranked causing the noise in something else, like someone said about the AHC pressures, rather than the torsion bars themselves being noisy.

I admit I know close to nothing about torsion bars. But that’s what we cranked to level the car. Little bit one one side, little more on the other, back and forth until the heights were even on the front. Before I had a saggy drivers side.
It would be best to get Techstream and get your pressures figured out. Though I don’t think it is related to your issue. At this point you’ve replaced so much i would try to stick a GoPro under there or some other camera to try and see what’s going on. I feel like we’ve covered every part that could be loose and at this point just guessing without putting hands on the vehicle.

More guesses: engine mounts?
 
@Das Shtig I’d be very inclined to look closely at your sway bar link ends. The fact you get the thunk/clunk whilst stationery but raising/lowering the vehicle suggests to me (from personal experience) that your link ends/cushions/cups could well be pinching and releasing as the loading shifts with height. You’ve had lots of work done on your front end to date so it may we’ll be any number of things but just try disconnecting the link ends and tie the bar out of harms way and see what the result is. Those link ends are under quiet a bit of strain with suspension articulation and can make all sorts of thunks and clunks if they release any bound up tension.
I’ve some photos of a shock actuators internals if you’re interested. They are just a free bleeding multi drilled piston with what looks like a progressive style stacked disc arrangement working in a inner liner cylinder tube that’s separate to the outer structural shock body tube.
 
It would be best to get Techstream and get your pressures figured out. Though I don’t think it is related to your issue. At this point you’ve replaced so much i would try to stick a GoPro under there or some other camera to try and see what’s going on. I feel like we’ve covered every part that could be loose and at this point just guessing without putting hands on the vehicle.

More guesses: engine mounts?

Engine mounts seem to be ok.

I drove the car over to Lexus of Orlando’s sister store, Lexus of Winter Park, today to see if their service manager would be more accommodating. He was. He treated me as a one ought to treat a Lexus customer—which is half the reason I go to the dealer for anything! The other half is competence. To that effect, he set me up with his specialist tech supervisor or whatever his title was, and we went for a test drive where the noise was heard loud and clear. I gave them the rundown on what I’ve done to the car—things I’ve replaced and that them we messed with the torsion bars. I feel much better about everything but we’ll see what the outcome is. I haven’t been told anything regarding my $800 but I’m hoping I just come out of this with my issue at LEAST identified. But I have a feeling they might go the extra mile since I had a bad experience.
 
@Das Shtig I’d be very inclined to look closely at your sway bar link ends. The fact you get the thunk/clunk whilst stationery but raising/lowering the vehicle suggests to me (from personal experience) that your link ends/cushions/cups could well be pinching and releasing as the loading shifts with height. You’ve had lots of work done on your front end to date so it may we’ll be any number of things but just try disconnecting the link ends and tie the bar out of harms way and see what the result is. Those link ends are under quiet a bit of strain with suspension articulation and can make all sorts of thunks and clunks if they release any bound up tension.
I’ve some photos of a shock actuators internals if you’re interested. They are just a free bleeding multi drilled piston with what looks like a progressive style stacked disc arrangement working in a inner liner cylinder tube that’s separate to the outer structural shock body tube.

It’s in Lexus’ hands again for now but I’ll let you know what happens. I would be very interested in the pics of the shock internals.

Thanks everyone for the advice! I’ll keep you posted.
 
It’s in Lexus’ hands again for now but I’ll let you know what happens. I would be very interested in the pics of the shock internals.

Thanks everyone for the advice! I’ll keep you posted.
Here’s what the piston and valve stack look like. Front actuator, upside down and the inner tube cylinder (that the piston strokes in) is completely removed. The retaining nut isn’t lockwired or loctited so it’s not impossible for it to loosen I suppose. Regardless, changing shock actuators didn’t correct your suspension related noise so it wasn’t that.

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^^^^^ Wow, that is a really robust design. Did not expect to see such substantial internals.

Thanks for posting.

I can now easily understand why they are fairly expensive.
 
^^^^^ Wow, that is a really robust design. Did not expect to see such substantial internals.

Thanks for posting.

I can now easily understand why they are fairly expensive.
Agreed, the hydraulic elements of this system are of very high quality and robustly engineered. Toyota didn’t skimp on this platform and it’s active suspension at all. Having spent close to three decades in military servo control/hydraulics and related fields I’d comfortably compare the overall quality of engineering design and build to mil spec equipments. It just needs a little basic routine maintenance, like any system.
 
Update: It’s still in the dealership’s hands with no diagnosis.

Possibly relevant info/guilty admission: I haven't touched the AHC fluid since I've had it (2 years, 80k miles). I don't know if it's still fine or what, don't know if that could be a factor. I believe it was changed shortly before I bought it. Not sure I want to mention it to them since I’d prefer to change it myself for the price of a can of fluid instead of the full dealership cost. Maybe they’d give me a break ::shrug::

What do you guys think?

Again, symptoms are:
-audible noise from front passenger suspension
-occurs semi-consistently under variety of conditions including:
-lowering AHC to L (inconsistent)
-stepping on pass side running board (inconsistent)
-full lock turns over bump or dip, forward (more consistent)
-speed bump, dip or undulation (semi consistent)
-car being “cold/warm” irrelevant

Any ideas about cause?
Should I mention the lack of AHC fluid change to dealer at this point?
Please advise!
 
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OK, so update… First, the AHC fluid was drained and refreshed a few weeks ago when they replaced my front “shocks.” So that’s all well and good and not the problem. They are telling me however, they think the problem might be a body to chassis bushing in the front passenger side area, above the running board maybe? They are telling me that they don’t do this in house, but outsource it to a body shop who has to take the body off of the chassis to replace this bushing. That sounds like a nightmare, and I’m wondering what you guys think about all of this. The diagnostic specialist working on it says he’s not a hundred percent sure yet, but his chassis ears are indicating that may be the problem. They also haven’t mentioned whether or not they would be helping $olve this problem after the shock debacle. But anyway, wondering if anyone has experience with this, or could give me some input or advice or some kind of spell I could cast on my truck. Thanks in advance!
 
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The first and cheapest thing to do is what paddo suggested. Eliminate alle the parts and joints of the sway bar.

I have also seen that sometimes a noisy ball joint can be hard to diagnose.
Another easy check is the spindle bearing. Just push the drive shaft in a bit to see that the bearing/shaft is not dry. If it is, it makes a funny noise.
Body mounts are a bit far fetched, but possible. And it is probably possible to fix without lifting the body off.
 
I had a body mount go bad on a 4runner and you could tell it was a body mount. The noise sounded like something banging on the body of the car, not a suspension noise, can you tell a difference?

Also don’t know why they’re trying to avoid doing it, but a body mount is replaceable without removing the body.
 
The first and cheapest thing to do is what paddo suggested. Eliminate alle the parts and joints of the sway bar.

I have also seen that sometimes a noisy ball joint can be hard to diagnose.
Another easy check is the spindle bearing. Just push the drive shaft in a bit to see that the bearing/shaft is not dry. If it is, it makes a funny noise.
Body mounts are a bit far fetched, but possible. And it is probably possible to fix without lifting the body off.

Is it possible to see the body mount to inspect it? I ask because the tech said there’s no way to inspect it to see if it’s bad. He apparently has to use chassis ears. Is this correct or what?
 
Also, I asked the tech to take a close look at the sway end links, but I didn’t want to ask him for too much other stuff... afraid to offend him, don’t want him to think I’m insulting his intelligence. He is the diagnostic specialist after all.
 
Is it possible to see the body mount to inspect it? I ask because the tech said there’s no way to inspect it to see if it’s bad. He apparently has to use chassis ears. Is this correct or what?

You can see them enough to tell if they've been moving. Look for yourself. There is one right in front of your passenger side tire (behind the bumper) mounted on the frame. You can clearly see the rubber mount/bushing.

Then the next one is to the rear of your passenger front tire just in from the running board, mounted on the frame. Again...you can easily see most of the bushing.

Now...you might not be able to tell the complete condition of the bushing...since part of it goes down into the mount, but it doesn't look like it would be necessary to lift/remove the body entirely from the frame to replace one.

Mine are not cracked or stressed looking. There is no indication (on the floor pan) that the bushing (where it contacts the body) has been moving fore or aft or side to side. The only other direction it could move is up or down. Tighten the nut that goes down through the center of it (if it will) and see if your noise goes away.

I can't see it being a body mount...but who knows.
 
Thanks. I’d get under it myself but it’s at the dealer. Long story, see above. They’re diagnosing it for free right now so I’ll ask them to do this stuff.
 

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