I fitted 10mm packers a few years back and, at best, saw 0.2MPa pressure drop. Not worth bothering with really other then helping a rear lean. 30mm packers should net you 0.5-06MPa pressure drop. You can add the 30s over the 10s too.
Definitive list of AHC maintenance items (1 Viewer)
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PabloCruise
SILVER Star
Anyone who is struggling with TechStream, read here - easy-peasy: How-To: TechStream In 5 Minutes
I got a reading today: 6.9 F & 5.8 R. After ~ 9 months and 10k miles on the King springs now.
Hello, I just want to chime in here to say hi and say THANKS! to @PADDO and others for the invaluable information on the AHC system. I managed to fix my problems this weekend.
My 2003 LX470 has a pretty bouncy ride for the past year and I was worried how much it's going to cost to fix it, and was seriously considering selling the car instead. But after reading all the info here and some youtube videos I was confident I could do it myself. And I was able to find and purchase 4 new OEM accumulators from Japan on ebay. The list price for them was $1039.90 for four globes, and with a $100 off coupon, I managed to score them for just $939.90 shipped!
Then I purchased 4L of AHC fluid from ToyotaPartsDeal.com and rented a clutch fan wrench set from AutoZone (deposit $100, but otherwise free) for the 36mm skinney wrench.
My LX is from the midwest and has quite a bit of under carriage rust, and it took me several hours to loosen the drain plugs. They're supposed to be 10mm and after brushing/cleaning all the rust aside, I was able to use a 9mm wrench to loosen it (HA!). I ordered new drain plugs and plan to flush the system once again in a few weeks and replace all the drain plugs then.
Unfortunately, there is so much rust on the rear globes the 36mm wrench couldn't fit in (due to the bubbling rust), and there's no 37mm wrench available, so I wasn't able to loosen them. So I had to give up. But after test driving with just new front globes, the bounce is gone and it drives like a dream and handles much better on turns. So the rear may not need replacement after all.
If anyone have any tips on removing the rear globes let me know. I may try again when I flush the system again in a few weeks. Otherwise, I may put up the two new rear globes for sale
My 2003 LX470 has a pretty bouncy ride for the past year and I was worried how much it's going to cost to fix it, and was seriously considering selling the car instead. But after reading all the info here and some youtube videos I was confident I could do it myself. And I was able to find and purchase 4 new OEM accumulators from Japan on ebay. The list price for them was $1039.90 for four globes, and with a $100 off coupon, I managed to score them for just $939.90 shipped!
Then I purchased 4L of AHC fluid from ToyotaPartsDeal.com and rented a clutch fan wrench set from AutoZone (deposit $100, but otherwise free) for the 36mm skinney wrench.
My LX is from the midwest and has quite a bit of under carriage rust, and it took me several hours to loosen the drain plugs. They're supposed to be 10mm and after brushing/cleaning all the rust aside, I was able to use a 9mm wrench to loosen it (HA!). I ordered new drain plugs and plan to flush the system once again in a few weeks and replace all the drain plugs then.
Unfortunately, there is so much rust on the rear globes the 36mm wrench couldn't fit in (due to the bubbling rust), and there's no 37mm wrench available, so I wasn't able to loosen them. So I had to give up. But after test driving with just new front globes, the bounce is gone and it drives like a dream and handles much better on turns. So the rear may not need replacement after all.
If anyone have any tips on removing the rear globes let me know. I may try again when I flush the system again in a few weeks. Otherwise, I may put up the two new rear globes for sale
Welcome and glad you’re on top of things. A BFH and cold chisel will shift your stuck-on rear globes. They are thick walled so you won’t puncture them with a few lefty-loose whacks.Hello, I just want to chime in here to say hi and say THANKS! to @PADDO and others for the invaluable information on the AHC system. I managed to fix my problems this weekend.
My 2003 LX470 has a pretty bouncy ride for the past year and I was worried how much it's going to cost to fix it, and was seriously considering selling the car instead. But after reading all the info here and some youtube videos I was confident I could do it myself. And I was able to find and purchase 4 new OEM accumulators from Japan on ebay. The list price for them was $1039.90 for four globes, and with a $100 off coupon, I managed to score them for just $939.90 shipped!
Then I purchased 4L of AHC fluid from ToyotaPartsDeal.com and rented a clutch fan wrench set from AutoZone (deposit $100, but otherwise free) for the 36mm skinney wrench.
My LX is from the midwest and has quite a bit of under carriage rust, and it took me several hours to loosen the drain plugs. They're supposed to be 10mm and after brushing/cleaning all the rust aside, I was able to use a 9mm wrench to loosen it (HA!). I ordered new drain plugs and plan to flush the system once again in a few weeks and replace all the drain plugs then.
Unfortunately, there is so much rust on the rear globes the 36mm wrench couldn't fit in (due to the bubbling rust), and there's no 37mm wrench available, so I wasn't able to loosen them. So I had to give up. But after test driving with just new front globes, the bounce is gone and it drives like a dream and handles much better on turns. So the rear may not need replacement after all.
If anyone have any tips on removing the rear globes let me know. I may try again when I flush the system again in a few weeks. Otherwise, I may put up the two new rear globes for sale
WOW. What a thread! All the info here is great! Thanks to all who have contributed! This definitely helps build the confidence for getting into the system.
After checking the status of where the AHC on my truck sits, I have a few questions.
I checked the hub center to fender measurements today and I think they all look pretty good.
FL - 19.5"
FR - 19.25"
RL - 20.25"
RR - 20.5"
It's not worth messing with these numbers, right? Perhaps 1/2 - 1 turn CCW on the left and 1/2 - 1 turn CW on the right to fine tune the centering? I'm conflicted due to anal retentivity.
Here are my numbers through TiS:
The front right and rear HC sensors are right at the spec line. Is it worth fiddling with them a bit or will that be like "chasing my tail"?
Both pressure sensor readings are high so I'll crank on the TB's to get the front in spec. The rear I'll have to figure out whether to get some springs and/or spacers to bring that down.
As far as the steering angle, that reading is with the steering wheel straight. It doesn't take much to move that number. But since this is close to the value that determines the open/close of the valve between the FL and FR, is it worth adjusting this? Is the procedure just a matter of twisting the tie rods?
Lastly, after reading all the threads that I have about this system, it seems that the rear has more of a broad range for set up. The front looks to be as simple as adding more preload to the torsion bars but the rear involves spacers, new springs or even both. What thoughts are there about why, despite having all new components(specifically OEM springs) would the rear still show out of spec? That is assuming that the system was within spec from the factory.
Thank you for any input/thoughts on my questions here!
After checking the status of where the AHC on my truck sits, I have a few questions.
I checked the hub center to fender measurements today and I think they all look pretty good.
FL - 19.5"
FR - 19.25"
RL - 20.25"
RR - 20.5"
It's not worth messing with these numbers, right? Perhaps 1/2 - 1 turn CCW on the left and 1/2 - 1 turn CW on the right to fine tune the centering? I'm conflicted due to anal retentivity.
Here are my numbers through TiS:
The front right and rear HC sensors are right at the spec line. Is it worth fiddling with them a bit or will that be like "chasing my tail"?
Both pressure sensor readings are high so I'll crank on the TB's to get the front in spec. The rear I'll have to figure out whether to get some springs and/or spacers to bring that down.
As far as the steering angle, that reading is with the steering wheel straight. It doesn't take much to move that number. But since this is close to the value that determines the open/close of the valve between the FL and FR, is it worth adjusting this? Is the procedure just a matter of twisting the tie rods?
Lastly, after reading all the threads that I have about this system, it seems that the rear has more of a broad range for set up. The front looks to be as simple as adding more preload to the torsion bars but the rear involves spacers, new springs or even both. What thoughts are there about why, despite having all new components(specifically OEM springs) would the rear still show out of spec? That is assuming that the system was within spec from the factory.
Thank you for any input/thoughts on my questions here!
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I’d put 3 cw turns on the right, 2 cw on the left. Don’t touch your height sensors because the tb adjustments will close that small gap.
For your steering angle you rezero that buy pulling your battery lead (I do 15-20 minutes - don’t touch TREs) to clear the AHC ECU memory. You must do this with the wheels straight ahead, this is important! The “degrees” represented there aren’t conventional degrees ie 1/360. If you do a lock to lock rotation of the steering wheel you’ll turn about 2.4 full turns or 860 degrees but the system will register from -1150 to +1150 “degrees” - go figure? - anyway it’s important to null this value occasionally but it’s not as dire as it would appear on face value. You actually have to throw the vehicle around a bit to get the gate valves to operate (they are SLFG & SLRG in your data list - solenoid Front gate/solenoid rear gate) as the system uses speed and steering wheel angle for their activation.
Rear pressures. Paul and I had many good conversations on (your I think) vehicles system. You’re right in that the FSM range is quite broad and all the evidence indicates that new coils don’t lower the systems pressure much below the upper end of the range. I don’t know the origins of Toyota’s numbers but I do know that getting pressures closer to 6 with the addition of a spacer tends to give a bit better ride and it maximizes your passenger/cargo/towing capacity. At 6.8 you could do nothing for a long time and be happy, or if you’re looking for something to do you could fit 30mm spacers.
Hope his is helpful.
For your steering angle you rezero that buy pulling your battery lead (I do 15-20 minutes - don’t touch TREs) to clear the AHC ECU memory. You must do this with the wheels straight ahead, this is important! The “degrees” represented there aren’t conventional degrees ie 1/360. If you do a lock to lock rotation of the steering wheel you’ll turn about 2.4 full turns or 860 degrees but the system will register from -1150 to +1150 “degrees” - go figure? - anyway it’s important to null this value occasionally but it’s not as dire as it would appear on face value. You actually have to throw the vehicle around a bit to get the gate valves to operate (they are SLFG & SLRG in your data list - solenoid Front gate/solenoid rear gate) as the system uses speed and steering wheel angle for their activation.
Rear pressures. Paul and I had many good conversations on (your I think) vehicles system. You’re right in that the FSM range is quite broad and all the evidence indicates that new coils don’t lower the systems pressure much below the upper end of the range. I don’t know the origins of Toyota’s numbers but I do know that getting pressures closer to 6 with the addition of a spacer tends to give a bit better ride and it maximizes your passenger/cargo/towing capacity. At 6.8 you could do nothing for a long time and be happy, or if you’re looking for something to do you could fit 30mm spacers.
Hope his is helpful.
Here’s an observation that I’ve made when checking the AHC fluid level: The fluid or the system is sensitive to temperature. I have noticed that when checking the fluid when cold it appears low, but after driving for a while to get the truck/system up to normal temp it shows normal like with ATF. I searched for this but didn’t find anything.
This morning I checked the fluid and thought it was low so I topped it off. After driving a couple of hours it is now over the MAX line. It’s not so much as to overflow but I’ll need to siphon some out.
I followed the owners manual on how to check.
Anyone else seen this?
This morning I checked the fluid and thought it was low so I topped it off. After driving a couple of hours it is now over the MAX line. It’s not so much as to overflow but I’ll need to siphon some out.
I followed the owners manual on how to check.
Anyone else seen this?
DirtDawg
"It'd be alot cooler if you did"
The AHC reservoir level doesn’t really mean much, as its just a holding tank. It’s not a recirculating system so it is not sensitive to fluid level.
It’s just there to make sure you have the proper amount of fluid/displacement for adjustment through the different heights.
That’s what I figured. I was using the level to monitor for leaks between times I’m under the truck. One of the shocks was noted as having some fluid on it at some point. This system is new to me so I’m learning more about it all the time.
DirtDawg
"It'd be alot cooler if you did"
The system should typically be leak free if it’s functioning properly. Weeping shocks is usually due to improper pressures.
Thanks. The pressures are not bad but could use some tweaking which I’ll do soon.
PabloCruise
SILVER Star
I was going back through my AHC adventures and noticed something...
Before I installed King rear springs, the last rear pressure readings I got were 6.9. This was after cross-level, adjust front t-bars and install 30mm spacers:
That was mid-July, so about 9 months ago and about 10k miles ago. After I installed the King rears, my laptop suffered an unfortunate demise as my wife's chihuahua peed on it.
Now I got TechStream working on a new laptop, but now running v12, vs v7 I was running last summer. But I notice my rear pressure is down around 5.8. I was thinking the rear springs would have lowered my rear pressures down more:
I finally got around to tweaking the system a bit. I put 1.5 turns CW on the left and 2.5 turns CW on the right. That leveled the front out at 19.5". The left rear is still ~1/4" lower than the right rear. The pressures are in spec now as can be seen below. The ride is great, although it was before when I bought it. I just wanted to baseline and know where I stand in the system. The anal side of me wants to mess with the FR and RR height control sensors but I'm not going to mess with that for now as I don't feel like chasing my tail with that. Thanks @PADDO for the tips!
2006 LC with 175k miles, 3 full turns on both sides. This was my first time ever touching the TBs and they didn't put up much of a fight. No record of them having ever been touched before: A little douse of Kroil beforehand and they moved pretty easily. If nothing else maybe this will serve as a reference point, thanks to the info here I decided to tackle this and was surprised by how easy it was.
Before:
After:
Before:
After:
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I got my scanner from work, didn't have techstream but it was able to read the pressure sensors.
Truck in N, full tank of gas, those were the readings. How many turns on the TB do i need to get the front down? As far as the rear, seems like i need to add a 30mm coil spring spacer?
Truck in N, full tank of gas, those were the readings. How many turns on the TB do i need to get the front down? As far as the rear, seems like i need to add a 30mm coil spring spacer?
After changing L to H to N a few times for a few days and registering the values anywhere from 4 to 11, i decided to stop reading to much into these and worry about ice-cream instead. My ride is buttery smooth, 12 notches on the tank delta ..and I have messed up a few fine vehicles up in past by this OCD and male delusion of control. Just me, I am not giving any directions to anyone, simply sharing my thought process flow chart.
Are the readings the same after you change from L to H a few times in your case?
Are the readings the same after you change from L to H a few times in your case?
N Pressure readings for torsion bar preload setting are only of value when taken with the vehicle settled after raising from L to N. Additionally, the FSM states that the rear pressure value needs to be taken with the temperature sensor disconnected. Others have seen high rear pressure values read lower when measured as per the FSM.
Not sure why L to H is being mentioned as that’s appropriate for the reservoir graduation count which is a very generalized damper globe health check. Two different checks. Of course the L to H reservoir graduation check should be done when neutral pressures are optimized, or at least within their design ranges, for accuracy.
I now augment Techstream pressure readings with mechanical gauge readings if there’s any question as to the Techstream values validity. I’ve just seen too many spurious Techstream/reader numbers.
Not sure why L to H is being mentioned as that’s appropriate for the reservoir graduation count which is a very generalized damper globe health check. Two different checks. Of course the L to H reservoir graduation check should be done when neutral pressures are optimized, or at least within their design ranges, for accuracy.
I now augment Techstream pressure readings with mechanical gauge readings if there’s any question as to the Techstream values validity. I’ve just seen too many spurious Techstream/reader numbers.
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Possibly my background in Metrology is the culprit and fails me. The L to H and back procedure is an important part in any gauge metrological verification/calibration and the delta is called Variation - an important characteristic. Ideally, the delta should be zero. Again, not arguing, as I don't really know the fundamentals behind the FSM recommendation, simply explained my thinking process behind the findings.
[before anyone jumps in after mistaking Metrology for Meteorology, it's a science of measurements and math processing of the time series, originates from the Greek word 'metros' - to meter, take a measurement. ]
[before anyone jumps in after mistaking Metrology for Meteorology, it's a science of measurements and math processing of the time series, originates from the Greek word 'metros' - to meter, take a measurement. ]
2001LC
SILVER Star
How do you disconnect the temperature sensor?
