Fluid Leak (AHC problem)

[Tech Noir]

Had an AHC sensor replaced in my LX470 by my mechanic and now the rear of the truck rides extremely high and bounces like a pogo stick on a trampoline. Also when I woke up this morning I noticed a fluid leak on my driveway.

It begins right in front of the rear left driver's side wheel which is where the new sensor was installed as well.

Picking up some rhino ramps from Advance Auto Parts today to try and take a look at the sensor myself since I know they're adjustable. And worse comes to worse I'll just try and remove it entirely as it was much less bouncy when it had no sensor.

 

[Chuychanga]

I have nothing to add about the bulk of your problem, but you don't need ramps to mess with the rear height sensor. It's easy to get to with the cruiser on ground level.

 

[2001LC]

Likely sensors height needs adjust down. Just loosen 10mm nut holding sensor arm in slide (with engine off). Slide it down just below middle of slide. See how that looks/works.

We actually use tech steam to read pressure. Which condition of rear coil springs, globes and accumulator are factored in. In new AHC system, target pressure for rear set at factory height, is 5.6Mpa.

The leak does not look like AHC fluid, but perhaps it dried with something it washed down remaining as that white look. Like road salts from melting ice in wheel well, looks a lot like that white after drying.

But, check to see if any fluid low, and look for wet areas on parts of underside, like shocks. No need for ramps. Just set AHC to high, than turn engine off. Toss something down on ground to lay on, carpet or cardboard work well. Get a flash light and look around underside for wet spots. Have camera in hand with flash on.

BTW: I'd give mechanic a chances to correct, as everyone has bad days. But, you may want to find another mechanic. As very few understand our AHC system.

 

[Tech Noir]

Likely sensors height needs adjust down. Just loosen 10mm nut holding sensor arm in slide (with engine off). Slide it down just below middle of slide. See how that looks/works.

We actually use tech steam to read pressure. Which condition of rear coil springs, globes and accumulator are factored in. In new AHC system, target pressure for rear set at factory height, is 5.6Mpa.

The leak does not look like AHC fluid, but perhaps it dried with something it washed down remaining as that white look. Like road salts from melting ice in wheel well, looks a lot like that white after drying.

But, check to see if any fluid low, and look for wet areas on parts of underside, like shocks. No need for ramps. Just set AHC to high, than turn engine off. Toss something down on ground to lay on, carpet or cardboard work well. Get a flash light and look around underside for wet spots. Have camera in hand with flash on.

BTW: I'd give mechanic a chances to correct, as everyone has bad days. But, you may want to find another mechanic. As very few understand our AHC system.

Which bolt am I attempting to adjust here?

 

[ktmracer01]

Well....this looks unusual. The adjuster you have in the photo appears to be an aftermarket unit. That may be the start of your problem...however, it may not be.

Best place to start, get Tech Stream... How-To: Tech Stream In 5 Minutes

Here's a quick 'how to' guide on AHC sensor adjustment. AHC Sensor Adjustment

In your case, it appears that the adjustment tab has completely rusted off on your rear upper control arm and your "mechanic" made this aftermarket unit work by drilling a new hole on the rear control arm adjuster tab. The part that would be adjusting yur heighton the unit you picture above is the silver threaded piece. Loosen the jam nut on the lower heim on the end that is attached to the rear upper control arm and see if you can thread it in a little more. The objective here is to close the gap between the two heim joints (if possible).

Can you take more photos of the height sensor and how it was installed?

Here is a pic of the height sensors on the LX470. You want to refer to the bottom sensor in this picture.

 

[2001LC]

Oh that's not right. That's a front sensor turn buckle. Which is set in wrong hole of arm. You can use the turn buckle, but need a set fixed length of~84mm bolt to bolt center

Rear arm

 

[GTV]

That adjustable link shouldn't be there, they are used in the front, not the rear. It should also be mounted to the lower end of the arm, not the middle. Whoever worked on your truck doesn't know AHC. Shocker.

 

[Tech Noir]

The guy who sold me the truck gave me this aftermarket piece once it was delivered so I figured he had an idea what was the right one.

My mechanic definitely isn't familiar with the AHC system though. I've since scheduled an appointment with a Japanese specialized mechanic that I was recommended in a 100 series group so I'm hoping they can take a look at the truck and let me know what's what.

The height control is always set to "low" even though the back end is very high and only the front end adjusts with the system.

 

[Chuychanga]

Your lower bracket appears to be broken and missing a crucial section. There should be a slot below the bottom bolt. The bolt goes in that slot and can be adjusted up or down within it. Your slot is broken and half missing. Any chance your mechanic broke the park and just tried to make it work anyway?

Should look like this, except in this pic the vehicle has had a sensor lift and so it's all the way to the top of the slot. Yours should be lower in the slot than this pic. I wonder if you could mimic lowering it by shortenening your heim joint turnbuckle thing. Maybe that's why they added that when the slot rusted away. Probably be better to just by the new part.

 

[Tech Noir]

Your lower bracket appears to be broken and missing a crucial section. There should be a slot below the bottom bolt. The bolt goes in that slot and can be adjusted up or down within it. Your slot is broken and half missing. Any chance your mechanic broke the park and just tried to make it work anyway?

Should look like this:

View attachment 2934696

Ah alright I fully see the problem now.

Unfortunately I wouldn't know as the truck was previously stuck in a low setting as the previous owner had removed the old part that was there, forcing it into a permanent low setting with a light bouncy ride to make it drivable.

 

[Chuychanga]

Ah alright I fully see the problem now.

Unfortunately I wouldn't know as the truck was previously stuck in a low setting as the previous owner had removed the old part that was there, forcing it into a permanent low setting with a light bouncy ride to make it drivable.

See my edit. Maybe that's why someone added the heim joint, to make up for the broken slot.

 

[suprarx7nut]

Step 1: Buy new control arms so you have the correct mounting tabs.
Step 2: Acquire Techsteam.
Step 3: Prepare to throw the aftermarket sensor in the trash. They are almost always so bad they're unusable. Buy Aisin or OEM Lexus/Toyota.

 

[2001LC]

View attachment 2934637View attachment 2934638View attachment 2934639View attachment 2934641View attachment 2934642

The guy who sold me the truck gave me this aftermarket piece once it was delivered so I figured he had an idea what was the right one.

My mechanic definitely isn't familiar with the AHC system though. I've since scheduled an appointment with a Japanese specialized mechanic that I was recommended in a 100 series group so I'm hoping they can take a look at the truck and let me know what's what.

The height control is always set to "low" even though the back end is very high and only the front end adjusts with the system.

Oh man that is a rusty mess.

Slide which should be on control arm, is rusted away. So, someone has drilled a new hole to attach sensor arm to. This puts arm about 2 or 3" above stock height set/lock point in slide. Which may be why he moved to inner hole of arm, in attempt to make it work. Shortening turnbuckle, is only way to adjust with current set up. Unless you replace the upper control arm, which I would. By using a turn buckle from front as he's done here, you have some adjust-ability.

Sensors relay info (height of vehicle) to AHC computer. Your rear sensor is telling system your rear height is lower than it actually is. Sensor a simple device, with contact points inside. Arm moves the contact dial to the various points. Computer must detriment if actual height change or normal suspension movement of/while driving. I'd not thought about this before; But changing length (shortening) of arm by using center hole of arm rather than outer hole. May change rate of movement and confuse computer.

Also, Your mechanic may have used a front sensor, here in the rear. OEM Front sensor have an R or L on the black arm attached to it. If there is any difference in the sensor themselves, IDK.

 

[Tech Noir]

Oh man that is a rusty mess.

Slide which should be on control arm, is rusted away. So, someone has drilled a new hole to attach sensor arm to. This puts arm about 2 or 3" above stock height set/lock point in slide. Which may be why he moved to inner hole of arm, in attempt to make it work. Shortening turnbuckle, is only way to adjust with current set up. Unless you replace the upper control arm, which I would. By using a turn buckle from front as he's done here, you have some adjust-ability.

Sensors relay info (height of vehicle) to AHC computer. Your rear sensor is telling system your rear height is lower than it actually is. Sensor a simple device, with contact points inside. Arm moves the contact dial to the various points. Computer must detriment if actual height change or normal suspension movement of/while driving. I'd not thought about this before; But changing length (shortening) of arm by using center hole of arm rather than outer hole. May change rate of movement and confuse computer.

Also, Your mechanic may have used a front sensor, here in the rear. OEM Front sensor have an R or L on the black arm attached to it. If there is any difference in the sensor themselves, IDK.

I'm honestly thinking to just invest in a conversion into Landcruiser traditional suspension at this point.

 

[2001LC]

I'm honestly thinking to just invest in a conversion into Landcruiser traditional suspension at this point.

Yeah. You've likely more rust related AHC issues. Just waiting to flatten your wallet.

Personally, I'd look for a 100 series, with much less rust.

 

[Tech Noir]

Yeah. You've likely more rust related AHC issues. Just waiting to flatten your wallet.

Personally, I'd look for a 100 series, with much less rust.

How much do you think I could get if I tried to sell this one? I'm in the Northeast so lots of them have rust and such.

218000 miles

 

[2001LC]

For rusty LX w/218K miles, rides like a Pogo Stick with ass end in the air. One where year and condition unknown. In market I don't in look in (rust belt) ever. I've no idea!

 

[suprarx7nut]

I'm honestly thinking to just invest in a conversion into Landcruiser traditional suspension at this point.

I glossed over the rust when I first saw this on mobile. Looking again now and I might not chase after this one much.

I'm a big AHC advocate, but even I would contemplate a conversion with bad rust like that. When mounting brackets are crumbing away into the ether you can count on seal failures and pipe leaks soon.

As you hit on, the entire vehicle is compromised to some degree. Everything is more annoying with rust like that.