AHC Fluid Change How To -- Need Input (1 Viewer)

[landdriver]

Correct, you’ve got normal operation with a functioning pump. It’s not likely any air made it’s way into the system.

i have done all procedures on the flush. torsion bar adjustments, height check etc. the front end has very little rebound damping. should i give the fronts another bleed? fronts at 7.1 accumulator pressure at 10.5 rear at 6.1. half tank. Rig has a winch up front from the factory.

 

[PADDO]

i have done all procedures on the flush. torsion bar adjustments, height check etc. the front end has very little rebound damping. should i give the fronts another bleed? fronts at 7.1 accumulator pressure at 10.5 rear at 6.1. half tank. Rig has a winch up front from the factory.

I’d lower your front neutral pressure another 0.2-0.4 MPa. How many graduations are you counting on the L to H check? If you’re not getting air/foam out of the front hydraulic circuit and the fluid you do get is somewhat pinkish and not black/nasty then you probably don’t need more fluid exchanges and bleeding.

 

[landdriver]

I’d lower your front neutral pressure another 0.2-0.4 MPa. How many graduations are you counting on the L to H check? If you’re not getting air/foam out of the front hydraulic circuit and the fluid you do get is somewhat pinkish and not black/nasty then you probably don’t need more fluid exchanges and bleeding.

ill give that a shot, the front end seems to rebound just a tad too much on uneven concrete. the l to h check is good at 10. when i did the bleed two months ago made sure all the fluid coming out was the color from the new fluid in the reservoir.

Thanks, Paddo.

 

[UGN]

Replaced close to 2 litres of the old fluid in the reservoir tank with approximately 1.5 litres of the new fluid (Put the vehicle into L). It looks like someone previously set the fluid level much higher than the Max mark. Unfortunately I was afraid to touch any of the five bleeder plugs as all of them were rusted and couple were missing caps from the previous owner(s).

According to FSM if the vehicle is lowered the fluid is returned back to the reservoir tank from all four shock absorbers and the gas chambers. Basically the new and old fluid are mixed eventually even if it was not drained from the bleeder plugs (I did not want to end up with a leaking or broken bleeder plug and costly repair rather than gradually replace old fluid from the reservoir tank).

When I raised and lowered the vehicle couple times the new fluid did mix with the old one. I will do another replacement later once they are mixed completely.

 

[uHu]

The fluid will never mix properly, and far from completely, as it only goes back and forth in one pipe. There is no circulation. It's the fluid in the shocks and actuators that gets worn and contaminated. The only way to get it out is to open something close to each wheel.

 

[UGN]

The fluid will never mix properly, and far from completely, as it only goes back and forth in one pipe. There is no circulation. It's the fluid in the shocks and actuators that gets worn and contaminated. The only way to get it out is to open something close to each wheel.

Even if I use DS to bleed the old fluid from the front and rear accumulators (globes) and the suspension control pump (middle cylinder) and one or all of them start to leak/break/seize it would be hefty cost to even buy parts online in Canada and even much more expensive (30% more) from a local dealership. I do not know what else I could do without risking these very expensive parts.

 

[boca1]

Even if I use DS to bleed the old fluid from the front and rear accumulators (globes) and the suspension control pump (middle cylinder) and one or all of them start to leak/break/seize it would be hefty cost to even buy parts online in Canada and even much more expensive (30% more) from a local dealership. I do not know what else I could do without risking these very expensive parts.

View attachment 2117249

ebay is your friend

GENUINE LX470 OR LAND CRUISER 100 SET OF 4 SUSPENSION ACCUMULATORS 1998-2007 | eBay

4 NEW GENUINE TOYOTA/LEXUS SUSPENSION ACCUMULATORS. LX470 & LAND CRUISER 100 BUILT 1/1998 TO 8/2007 WITH AUTOMATIC. HYDRAULIC SUSPENSION ONLY. AND THE ONLY FLUID THAT CAN BE USED IS GENUINE TOYOTA AHC FLUID.

www.ebay.com

 

[UGN]

ebay is your friend

GENUINE LX470 OR LAND CRUISER 100 SET OF 4 SUSPENSION ACCUMULATORS 1998-2007 | eBay

4 NEW GENUINE TOYOTA/LEXUS SUSPENSION ACCUMULATORS. LX470 & LAND CRUISER 100 BUILT 1/1998 TO 8/2007 WITH AUTOMATIC. HYDRAULIC SUSPENSION ONLY. AND THE ONLY FLUID THAT CAN BE USED IS GENUINE TOYOTA AHC FLUID.

www.ebay.com

Thank you @boca1 unfortunately not every item ships to Canada from eBay. I will leave AHC suspension with the new fluid in the reservoir tank for now. It's much better than what was there before anyway

 

[LXPearl]

UGN, a full replacement of fluid in the reservoir is better than nothing, and if you lower the vehicle regularly upon stopping you are forcing additional circulation in the system as it will move back to N with each trip. That buys some time for a better solution. I would suggest purchasing replacement valves to do a full replacement of the fluid. I got flare wrenches and six sided box wrenches years ago for similar situations with brake valves.

 

[Sean Jones]

Completed a flush today. Many thanks to all who contributed to this thread. I have a couple nuggets to add...

1. I used PB Blaster and let it sit overnight. No problem at all opening the valves.
2. I used a tin can full of AHC fluid that was 2.5 L. What I did was take the 3/16 in gas rated tubing and put it in the empty can once I was done loading the reservoir. I rubber-banded the tube so as not to make a mess on the flat surface I was doing the repair on.
3. I used a 10 mm closed-end wrench and put it over the tube. Let me explain. You can take the can with the tubing attached, push the tubing on to the teat, the wrench is attached and you just slide the wrench up once you attach the tubing open it until enough fluid come that comes comes out and then close it back up. Then remove the tubing and the wrench is still there it's basically one package of the tin as a reservoir for the bleed and the wrench attached. It made it quite easy.
4. I went back and bled all 5 positions starting with PS and got more sludge then clean clear fluid. Accumulater was the only position that bled pure fluid immediately.

Thanks again!

Cheers!

 

[WeBeCinYa]

@PADDO are you in the Charlotte area to possibly assist with fluid swap? I noticed you had Charlotte on your profile. Novice here in need of some support.

 

[heidtman79]

@PADDO are you in the Charlotte area to possibly assist with fluid swap? I noticed you had Charlotte on your profile. Novice here in need of some support.

Let me know when you do this, I'm in the greater Charlotte area too and happy to help if my schedule allows. I plan to do this once I complete my fluid baseline, cv reboot, sunroof gasket replacement, heater T's, and other miscellaneous items. So probably by June . But I'm used to wrenching when I had an HJ60.

 

[WeBeCinYa]

I just went and checked my fluid and graduations. To start my fluid was low, it was below the minimum line by a few marks. Not sure if that skus the test but I put it in low and it rose above the full line. After it sat a bit I marked the line and then raised it to high. The difference between the low and high was 12 graduations. I assume even though I started low it still means the graduations are good?
I plan to change the fluid soon.

 

[OwnerCS]

I thank everyone here for contributing to this GREAT thread. I was able to get through the fluid change procedure in roughly an hour. Since mine was so dirty, I had to let the fluid drain for extra time to clear up. I used a fluid extractor to empty the fluid reservoir before I started the process. Since mine was extremely dirty, it took 3.5 liters to get mine running clear like I wanted.

I can tell it now lifts and lowers faster after the change. I'm getting 7+ graduations from low to high. In spite of the neglect, I think I have a solid AHC system.

I bought 4 liters of AHC fluid from Toyota Parts | Toyota Online Parts | Genuine Toyota Parts | Toyota Parts Online for $14.07 each before shipping. Delivered total was $74.44 for 4 liters.

Since this is an easy process and I cannot complain about the cost, I will check and change the fluid again if I see any change in color. I do think it is good to periodically exercise the system by changing the raise/lower settings from low to high.

 

[PabloCruise]

I thank everyone here for contributing to this GREAT thread. I was able to get through the fluid change procedure in roughly an hour. Since mine was so dirty, I had to let the fluid drain for extra time to clear up. I used a fluid extractor to empty the fluid reservoir before I started the process. Since mine was extremely dirty, it took 3.5 liters to get mine running clear like I wanted.

I can tell it now lifts and lowers faster after the change. I'm getting 7+ graduations from low to high. In spite of the neglect, I think I have a solid AHC system.

I bought 4 liters of AHC fluid from Toyota Parts | Toyota Online Parts | Genuine Toyota Parts | Toyota Parts Online for $14.07 each before shipping. Delivered total was $74.44 for 4 liters.

Since this is an easy process and I cannot complain about the cost, I will check and change the fluid again if I see any change in color. I do think it is good to periodically exercise the system by changing the raise/lower settings from low to high.

I try to change the fluid in the AHC every year.

 

[OwnerCS]

I try to change the fluid in the AHC every year.

Thank you. Good plan. I will do that also. I can feel the difference in the way it drives. Much better now.

 

[shiretowndown]

^ excellent, have you got your Techstream up and running to dial in your neutral pressures? Its very safe to say that if your torsion bars haven't been adjusted in a while (or ever) and coils are tired originals then your pressures will be much higher than the factory settings - to the detriment of your damping and overall ride quality.

So if I complete an AHC flush and I don't have Techstream, can I just take my LX to a Toyota dealer and ask them to verify/set my neutral pressures?

 

[uHu]

So if I complete an AHC flush and I don't have Techstream, can I just take my LX to a Toyota dealer and ask them to verify/set my neutral pressures?

In theory, yes, but most dealers do not have anyone who knows the ahc system well enough to know how. You have to choose your doctor well.

But, if you are brave enough to bleed the ahc (piece of cake), then adjusting torsion bars and changing coils would be easy for you.

 

[Stian747]

Gents,

100-series. Any thoughts/advice on this one? AHC acting strange lately and it has come of N and gone to L with the car at a standstill. Changed AHC oil 12 months ago.

 

[uHu]

Yes, your steel springs are doing F- all. If that reading is done after going from Lo to N, then either torsion bars and coils are much too weak or the height is adjusted above standard.
Time to study: Definitive list of AHC maintenance items