AHC Fluid Change 2.0

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OG 91 LC

OG 91 LC

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Hey fellas. I have read the PDF write up on the AHC fluid change- how to.
It's seems easy and straight forward.


I was just wondering. I'm assuming the fluid is one and the same throughout the system. May I do this instead.

1. Put the car in low and take out fluid from reservoir.

2. Refill the reservoir with fresh AHC fluid.

3. Get the car back to neutral.

4. Get the car to cycle through H, N, and L x amount of times and drive the truck around for days to get fresh fluid throughout the system.

5. Repeat steps 1-4 until pinkish fluid is constant in the reservoir after x amount of times of repeating 1-4.

This way there is no need for bottles, hoses, wrenching, and introducing air into the system. It's just a matter of swapping out fluids once in a while from the reservoir and refilling until desired fluid color has been achieved.

It's not an instant gratification type of service, but I arrive eventually to the same conclusion.

The only thing I can think of is how many cans it would take to achieve fresh fluids throughout the system after all that cycling.

What do you say fellas? Cool? Not cool?
 
Considering the system isn't a circuit I would be concerned about the time it takes to get new fluid to the extremities (if ever).

If you're nervous about doing it the 'right' way, don't be. It's an extremely simple job assuming your AHC bleeders aren't rusted.
 
Not cool, imo. As Mixelplix posted, AHC is not a hydraulic system with constant circulation, like the transmission.

Draining the accumulator and globes, per the FSM, allows the dirty fluid at the ends of the system to be flushed completely with new fluid...it also allows you to count your marks on the fluid tank for a general idea of how the system is working.

Flushing the AHC takes around 1 and one-thirds can of fluid and the job itself is stupid-simple. Time involved, about 20 minutes. Tool involved, a box wrench to fit the 5 AHC bleeder valves.

hth

Steve
 
I'm sure your method would be better than doing nothing, but with the price of fluid I think it would be much easier and cheaper in the long run to bleed it the proper way.
 
Ok. So first of all fluid introduced into the system via the reservoir does or does not circulate throughout the entire system; globes, accumulator, etc???

I guess there is one way to figure this out and that is to do it and see what happens.

Also. Since an issue that arises with bleeder bolts is rust, then one viable option for those that can't remove the bleeder bolts would be this method. Perhaps?

Just a thought.
 
OG 91 LC said:
Ok. So first of all fluid introduced into the system via the reservoir does or does not circulate throughout the entire system; globes, accumulator, etc???

I guess there is one way to figure this out and that is to do it and see what happens.

Also. Since an issue that arises with bleeder bolts is rust, then one viable option for those that can't remove the bleeder bolts would be this method. Perhaps?

Just a thought.
Click to expand...
The globes are closed and at the 4 ends of the circuit, as are the front shocks. You'll get fluid exchange to the extent that the globes and shocks are as full as they can be after you've added fresh AHC fluid to the reservoir.

Rusty bleeder bolts are a separate issue and need replacement so that the AHC system can be flushed correctly...otherwise I doubt Toyota would have provided the bleeders.

Steve
 
All the above posters are correct, to be effective a fluid exchange needs to be done through the five bleeder points. Certainly, if the bleeders have been allowed to corrode to the point they can't be used then incrementally exchanging fluid at the reservoir is better than nothing. It really is a simple job that is not even a one banana job - maybe 1/2 plantain at best. On the image you can see that a percentage of fluid goes back and forth between the functional elements and the reservoir through the one line, it doesn't circulate.
image.webp
 
You got some very good answers above here. Just adding my 50 c:
If you just compare the fluid you see in the reservoir with the sewage you get at the bleeders, you'll see that there is no point in doing anything at the resvoir end.
You should repeat the steps of bleeding at the bleeders and refilling at the top, with some driving and up/down action in between, because you will never be able to get all the old fluid out of the shocks and accumulators without removing them in order to drain them completely. So after bleeding once, you let the fluid move a bit back and forth between acc's and shocks, and then bleed a bit again. Let it sink all the way to the bump stops in order to push out as much as poss from the shocks.
 
Can someone tell me if 1 bottle of ahc fluid will be enough for a change out? Heading to Toyota now...
 
I'd grab an extra can if you can swing it. Always good to have extra..
 
Mud to the rescue! Gracias!
 
PADDO said:
Yep 1 can (2.5L) is all that's needed. Have a look at my "quick and easy 1 can method" just to make sure you don't remove more old fluid than you can replace.
Click to expand...

I always like posting a link when referencing a specific thread or post. I did not find a thread by @PADDO on the "1 Can Method", but I did find this post:

AHC Fluid Change How To -- Need Input
 
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