Gentlemen, how much AHC fluid do I need to change the fluid AND raise the truck 2"?
AHC Fluid Change How To -- Need Input (1 Viewer)
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About 1.6 containers is what it took me to do a complete flush. The 2" lift part is irrelevant; same amount of fluid is used regardless of if AHC is on H, M, or L.
DanInDenver
GOLD Star
No, No, No
You can't raise the truck by adding fluid!
You will need two cans for the change.
Are you doing a sensor lift and want to know what the additional volume is? If so I can tell you what the volumes of the front and rear shock actuators are, or you can just add more fluid to the tank until it's about right. If you are under the impression that more fluid will raise the height than, sorry don't work that way.
As long as the vehicle never came back down and overfilled the reservoir.
It's designed to operate at all ranges withing the factory min/max. More fluid doesn't buy you anything. If you're going higher than AHC "H" setting then I doubt you'd have much droop to play with, not to mention the higher globe pressures.
The chances of overflowing the reservoir are ridiculously small! And I'm well aware how the system is designed to work, but thanks.
Overfill risk depends upon how much he fills and at what position the shock is at when filled. And I certainly wasn't trying to short you on your system knowledge!
I'm still curious as to what would the value be in adding fluid? Whether you do a sensor lift or a electronic (Slee) lift, you'd still be in the factory range, no?
I'm still curious as to what would the value be in adding fluid? Whether you do a sensor lift or a electronic (Slee) lift, you'd still be in the factory range, no?
Yes, yes, yes. Sensor lift.....
Reading the many threads on the subject, I was reading where one fella suggested having more AHC juice on hand to do the sensor lift. Gave me the impression that at the new "neutral" height you would need more juice to get to the new "high" setting.
I already bought one can of AHC fluid as the fluid change threads did not specify an amount. In fact I was under the impression it was only one can to do the change. Glad I asked before I got stuck without enough. Off to order more blinker fluid ...
Thanks for thinking everyone is stupid, DanInDenver.
Reading the many threads on the subject, I was reading where one fella suggested having more AHC juice on hand to do the sensor lift. Gave me the impression that at the new "neutral" height you would need more juice to get to the new "high" setting.
I already bought one can of AHC fluid as the fluid change threads did not specify an amount. In fact I was under the impression it was only one can to do the change. Glad I asked before I got stuck without enough. Off to order more blinker fluid ...
Thanks for thinking everyone is stupid, DanInDenver.
hoser
SILVER Star
There indeed will be a little more AHC fluid "required" with the AHC lift. If you took a stock AHC equipped 100 and your AHC reservoir was at MAX level, upon going to HI mode, the AHC fluid level will drop ~4 gradations towards the MIN level or maybe lower. The system will work fine at the MIN fluid level (just as your brakes would) but if you wanted to maintain the same fluid level as "pre AHC lift," you would need an extra ~4 gradations fluid to get to MAX level.
did the fluid flush and bleed yesterday. It is indeed as simple a project as others have said. A couple comments
- it does take 2 x 2.5 liter cans of the toyota fluid. ended up with a few cups extra and just added it to the reservoir, taking the level above the Max mark but thats no big deal
- contrary to what others have said, I got far more out of each of the globes than the accumulator during bleeding, probably 3x
- if you're picky, have a supply of rubber bleed screw dust caps on hand; one of mine was rotted and needed to be replaced
- think mine was last changed 55k miles ago by prior owner. The old fluid had the appearance of dirty brake fluid. The new fluid is light pink
- i noticed an improved ride, but not dramatically so
- it does take 2 x 2.5 liter cans of the toyota fluid. ended up with a few cups extra and just added it to the reservoir, taking the level above the Max mark but thats no big deal
- contrary to what others have said, I got far more out of each of the globes than the accumulator during bleeding, probably 3x
- if you're picky, have a supply of rubber bleed screw dust caps on hand; one of mine was rotted and needed to be replaced
- think mine was last changed 55k miles ago by prior owner. The old fluid had the appearance of dirty brake fluid. The new fluid is light pink
- i noticed an improved ride, but not dramatically so
How are you all disposing of the used AHC fluid after flushing?
DanInDenver
GOLD Star
I took mine to local Walmart.
I recently purchased a pre-owned '03 LX with 72,000 miles and have been changing fluids and doing other 'baseline' maintenance. One thing I intend to do very soon is change the AHC fluid, not because the ride is harsh but because I believe it has not ever been changed. This thread along with a few others have been very useful in helping me prepare for the job and I thank you all in advance for your contributions.
I did have a question I hoped those of you with some experience might be able to answer. I have a mityvac bleeder pump which uses a vacuum to bleed a hydraulic fluid system. I bought it to make a one man job of bleeding and flushing the brake systems on my cars. I have used it countless times with great success on the brakes and I was hoping I might use this on the AHC system to pull the fluid from each bleed valve to make the process a bit quicker.
Has anyone used a vacuum pump for this before? Can anyone think of any cons to using one? I am thinking that with the truck in the LOW position, I can extract fluid starting from the valve furthest away from the reservoir until clean fluid comes through, then move to the other valves all the while making sure the reservoir does not run dry. Then once complete I can start the truck and it should all operate normally.
Any input or experience anyone has using a vacuum bleeder for this purpose would be greatly appreciated.
I did have a question I hoped those of you with some experience might be able to answer. I have a mityvac bleeder pump which uses a vacuum to bleed a hydraulic fluid system. I bought it to make a one man job of bleeding and flushing the brake systems on my cars. I have used it countless times with great success on the brakes and I was hoping I might use this on the AHC system to pull the fluid from each bleed valve to make the process a bit quicker.
Has anyone used a vacuum pump for this before? Can anyone think of any cons to using one? I am thinking that with the truck in the LOW position, I can extract fluid starting from the valve furthest away from the reservoir until clean fluid comes through, then move to the other valves all the while making sure the reservoir does not run dry. Then once complete I can start the truck and it should all operate normally.
Any input or experience anyone has using a vacuum bleeder for this purpose would be greatly appreciated.
No first hand experience, and it's been 30 years since I worked on hydraulic systems, but...
Virtually every hydraulic pump I worked on was of the positive displacement type. And with that sort of system you won't be able to pull fluid from the reservoir, only from the accumulator back. Or at least that's how such systems used to work. Something to think about - until someone with current knowledge jumps in to the discussion.
You do not need a vacuum to pull fluid through the five bleed points as they are under pressure whilst the vehicle is at a height above the front and rear bump stops. Just crack a bleed point and fluid will be expelled under pressure and the circuit being bled will lower. Hydraulic force actually holds the vehicle up and provides more static lift force than the torsion bars and coils. At the Low position with the vehicle off the pressure is approximately 3.5MPa at the four corner bleed points, and a bit higher at the height accumulator. It is a very simple, one person job, to methodically bleed through new fluid and its best to allow the vehicle to slump as low as practicable, to the bump stops, to get maximum fluid exchange out of this non reticulating system. Please, no vac system, just follow the established procedure and your system will be all the better for it.
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Yep, hydraulic principles hold pretty solid. The pump is a rotary gear pump with a pressure loading design.
Thank you for your responses guys. I will do it the way you recommend and outline in the thread which seems to be tried and true and will leave the vacuum bleeder for the brakes.
Only thought that comes to mind is if air could be introduced into the system once the shock compresses and reaches the stop. I suppose that if you guys have all done it with success that I will have no issue.
Thanks
Only thought that comes to mind is if air could be introduced into the system once the shock compresses and reaches the stop. I suppose that if you guys have all done it with success that I will have no issue.
Thanks
As long as you crack/close the bleeders as if you were doing brakes and don't run the reservoir empty you'll be fine.
So don't let it drop all the way down. The amount recommended in the PDF file attached to this post suggested a 6 ounces fluid bleed increment. When I did mine I started closing off the bleeder at around 4 ounces. I picked 4 ounces to start closing off the bleeder since I was concerned that the shock would bottom out because the wrench slipped, potentially resulting in air intrusion. Keep in mind I am an extreme newbie when it comes to the LC/LX mechanical world. Only CON was that I just had to do the bleeding cycle more times.
Just did the fluid change this past weekend so it's fresh in my mind. As soon as you open up the bleeder the truck will start to drop. My truck dropped all they way down quickly (a few seconds...depends on far you open the bleeder valve) and MAYBE 4 ounces of fluid came out (probably less) at each actuator. Fluid would still come out after the truck dropped down so I just closed the bleeder valve when the truck hit the bottom, refilled the reservoir if needed and drove it up and down the street to for the pump to level it out again. I did each actuator twice and the accumulator twice...one at a time with refilling and driving between each bleed before I saw fresh fluid coming through.
Ride definitely improved (07 LC w/ 100K and had not been done before) but it was not a night and day diff.
When you are all done, raise and lower the truck a time or two before you do your final fluid check in the reservoir.
no vacuum pump is needed
Ride definitely improved (07 LC w/ 100K and had not been done before) but it was not a night and day diff.
When you are all done, raise and lower the truck a time or two before you do your final fluid check in the reservoir.
no vacuum pump is needed
