AHC Fluid Problem

[2001LC]

That's one service manager, I'd avoid.

Where I have read in mud, of a Dealership buying a pump assembly due to bad fluid. I've never heard Toyota/Lexus corp., even hint at bad fluid or a recall.

If you can prove AHC working before, the AHC fluid from Toyota/Lexus Dealership plastic bottles poured in. That fluid was in sealed bottles, was/are jellying. That jelly, has damaged the AHC system. You've a case!

Question is how relentless are you, and what can you prove in a court of Law. Corp my want to buy your silence!

Second if you prove, that Toyota/Lexus, knew bottles contaminate and did not warn us. Then it becomes a very big ticket, Lawyers will get excited about.

Squeaky wheel get the grease!

You've a few choices:
1) Convert to none AHC.
2) Repair the system. If a system all rusted out, you've a lot work. Rust, sure isn't caused by jell. But wouldn't be an issue today, if weren't for jelly.

If you trying to preserve your legal rights. You'll need a lawyer before making any more moves. Likely you'll need not only documentation, witness and evidence. But you must give Toyota/Lexus opportunity to correct and document with witness you did.

They'll also have rights to inspect evidence. This is tricky, if you want a working AHC now. So written notice to Toyota/Lexus and giving them the opportunity they inspect and correct, before any corrective work you do, is key. They must respond within a reasonable time frame.
________________________________________

Personally, I only saw one case of jelly in AHC. AHC had gone into fail-safe (flashing OFF). Owner after reading self-help in mud, notice reservoir look a bit low. Having a 1L plastic bottle (sealed) AHC fluid, he'd purchased from ebay in 2021. He added some of the fluid, to see if AHC would then work. Which it didn't help at all, thankfully. When that didn't work, he called me. Upon questioning him, I learned he'd added fluid from plastic bottle. So I took a look in the screen under the reservoir cap. Sure enough, I saw nice clean jell in the screen. OH NO!

Good new was AHC was OFF (in failsafe). So pump never ran. So we suck all the fluid we could from reservoir. Then filled with good fluid from a 2.5L tin. Went on too diagnose AHC issue. Which was a broken wire at accumulator. Looks like a rodent chew partially through wire. Than months, possible years later, wire in broke. Spliced in a new pigtail, with butt solder heat shrink. AHC, fired up and all good. We were so thankful, the AHC hadn't come on with the jell in the reservoir.

 

[GremlinMobile]

Figured I'd update everybody on my saga. I contacted Lexus corporate regarding the contaminated AHC fluid I bought from one of their dealers. They told me to take my car to the dealer so the dealer could confirm the diagnosis of contaminated fluid. The service manager did this, and apparently called corporate directly to let them know. Who knows what that conversation was actually like.

Then, I believe Tracy, from corporate called me back and said that unfortunately Lexus can't help me. I was shocked that they're taking no responsibility for what is clearly their fault. She said that they can't verify that the fluid was not tampered with by me or that I did the drain and refill correctly. I guess it's my word against theirs. I told her they were sealed containers and I followed all manufacturer's directions to do this work. She didn't care. She just said "we can talk about this for a long time but the bottom line is that Lexus will not be helping you".

It's not often that I feel this helpless in a situation where I was blatantly wronged. Hiring a lawyer will cost more than this is worth. I guess I'll try to take the pump apart and **** the system up even more now.

 

[suprarx7nut]

I saw someone mention here something like "anyone who has tried to take these pumps apart was never able to get it working again". Besides that, bleeding the globes and accumulator is going to be an issue since the bleeders are super rusty - I think that's the biggest issue I'll have if I end up having to deal with this on my own.

Right now, at least the car rights in L but isn't on the bump stops. It's still usable. Once I start messing with the bleeders and everything, it'll be all or nothing.

Whoever said that is just wrong. Lots of people disassemble and reassemble and all is well. The vocal minority with problems come here. Thousands of successful services don't bother post up here to say, "success!"

Well I called Lexus corporate regarding their contaminated fluid breaking my pump and they told me to take the car to the dealer so they can inspect the problem to confirm that it was indeed the fluid that did it.

Upon arrival, the service manager laughed at me saying that Lexus corporate ain't gonna pay for fixing this. He seemed to be aware that there would be more to the fix than just swapping out the pump. He said the repair would cost 15-20k because everything is rusted and to properly flush out the contaminated fluid out of the components they'd likely have to replace a lot of components that are too corroded to take apart to clean. Well, just because the contaminated fluid caused 15-20k of damage to my car, that doesn't mean they shouldn't be responsible for bringing it back to the working condition that it was in before I used their defective AHC fluid.

I will keep you guys posted but it's not a good sign that the service manager laughed at my expectation that Lexus would take responsibility for the damage to my car. He also said he's never heard of contaminated AHC fluid. When asked if they stock it, he said no, they might have one bottle maybe but it's like $100/bottle so they don't keep it in stock..... makes me wonder. Don't people service their Lexus vehicles with AHC at this place? If so, aren't fluid flushes supposed to be done regularly? He admitted to having an 01 LX himself, but said that he had it converted to springs..

Yeah, no way Lexus is paying for anything for your diy service. Now if Lexus did 100% of the work with fluid they provide... Then they might. That's a part of why shops are so hesitant to work on high end cars. The liability for things to go wrong is huge and your rusted bleeders turn a $500 problem into a $10k problem.

No surprise a Lexus service guy is completely clueless. It's frustrating, but absolutely the norm.

It’s been my experience that shops just don’t want to mess with AHC. It’s not that complicated, but there’s too much that can go wrong so I don’t really blame them. For them it’s a lot easier just swapping shocks/struts.

Yup. Easy money is simple shocks and springs.

Figured I'd update everybody on my saga. I contacted Lexus corporate regarding the contaminated AHC fluid I bought from one of their dealers. They told me to take my car to the dealer so the dealer could confirm the diagnosis of contaminated fluid. The service manager did this, and apparently called corporate directly to let them know. Who knows what that conversation was actually like.

Then, I believe Tracy, from corporate called me back and said that unfortunately Lexus can't help me. I was shocked that they're taking no responsibility for what is clearly their fault. She said that they can't verify that the fluid was not tampered with by me or that I did the drain and refill correctly. I guess it's my word against theirs. I told her they were sealed containers and I followed all manufacturer's directions to do this work. She didn't care. She just said "we can talk about this for a long time but the bottom line is that Lexus will not be helping you".

It's not often that I feel this helpless in a situation where I was blatantly wronged. Hiring a lawyer will cost more than this is worth. I guess I'll try to take the pump apart and **** the system up even more now.

It's perhaps a good example of legal liability in life and why prices for sooooooo many things around us include a huge percentage for "liability". A business doesn't just need to cover the cost of what they're doing, but also the cost of insurance and the general admin time and cost sink that comes along with any surprise issue or lawsuit.

Good luck on the service! You're going to want those bleeders to function so I would start there. Pretty much guaranteed fair if you can't bleed at least at height accumulator.

You might need to plan on buying a few components. Height accumulator, perhaps the actuators all around (that's the part that has the bleeder near each globe).

 

[GremlinMobile]

Thanks for the input. I'm wondering if taking the pump out to clean and re-install inevitably introduces air into the system and necessitates me having to bleed the accumulator. My bigger issue I think is that I have a seized accumulator bleeder. I might even be able to bleed the globes, if I have to, but the accumulator is stuck solid.

 

[suprarx7nut]

Thanks for the input. I'm wondering if taking the pump out to clean and re-install inevitably introduces air into the system and necessitates me having to bleed the accumulator. My bigger issue I think is that I have a seized accumulator bleeder. I might even be able to bleed the globes, if I have to, but the accumulator is stuck solid.

Ever used an inductive bolt heater? Now might be your introduction, lol.

 

[GremlinMobile]

Have to say I didn't know such a thing exists. Someone else suggested heating the bleeder on a different thread but people had concerns of heating up highly pressurized hydraulic fluid. You don't think it's a concern?

By the way, last night I was able to crack all four bleeders on the globes. The accumulator bleeder didn't budge yet. I left a rag soaked with penetrant wrapped around the bleeder so I'll let it soak a while and try again. Wonder if I can rent the induction bolt heater somewhere.

 

[Rhetoric]

Have to say I didn't know such a thing exists. Someone else suggested heating the bleeder on a different thread but people had concerns of heating up highly pressurized hydraulic fluid. You don't think it's a concern?

By the way, last night I was able to crack all four bleeders on the globes. The accumulator bleeder didn't budge yet. I left a rag soaked with penetrant wrapped around the bleeder so I'll let it soak a while and try again. Wonder if I can rent the induction bolt heater somewhere.

Keep soaking it. The more the better. I love Kroil for these jobs, but PB Blaster has also worked for me on stubborn stuff and dedicated soaking.

I think the concern with heating is the "usual" way of heating with a torch, which gives a lot of variance as to where that heat is going. The induction bolt heater sounds nifty.

Another option if you have an air hammer is the Phoenix Systems Brake Free Bleed Screw Remover. Or finding a shop that has one and will do that task for you.

 

[lx200inAR]

Just popping in here to clear up some of the history as far as what seems to have been possible in resolving this issue.

Whoever said that is just wrong. Lots of people disassemble and reassemble and all is well. The vocal minority with problems come here. Thousands of successful services don't bother post up here to say, "success!"

This may have been me, as I've definitely said something similar in the 200 series forum. I've been following the bad fluid saga in the 200 series forum since it started (I bought my LX just before the reports started coming in).

I've yet to see a thread where someone actually split the pump and was able to reassemble it and have a functioning pump. I certainly don't believe that it's impossible to do, but that there is no "blueprint" for accomplishing it yet posted anywhere I've seen. I believe when I posted that, it was to suggest that taking the pump out and cleaning all the mesh screens and ideally priming it with fresh fluid is was what I would do first, because splitting the pumps had been fruitless to that point (2-3 different threads with failed attempts).

And to add some color to what I've seen about Toyota/Lexus resolving issues, it's only been when the dealer was actually doing the service and put the bad fluid in themselves. I think as you are finding out, you will have a tough time getting them to provide any relief when all they did is provided the fluid.

 

[IndroCruise]

Just popping in here to clear up some of the history as far as what seems to have been possible in resolving this issue.



This may have been me, as I've definitely said something similar in the 200 series forum. I've been following the bad fluid saga in the 200 series forum since it started (I bought my LX just before the reports started coming in).

I've yet to see a thread where someone actually split the pump and was able to reassemble it and have a functioning pump. I certainly don't believe that it's impossible to do, but that there is no "blueprint" for accomplishing it yet posted anywhere I've seen. I believe when I posted that, it was to suggest that taking the pump out and cleaning all the mesh screens and ideally priming it with fresh fluid is was what I would do first, because splitting the pumps had been fruitless to that point (2-3 different threads with failed attempts).

And to add some color to what I've seen about Toyota/Lexus resolving issues, it's only been when the dealer was actually doing the service and put the bad fluid in themselves. I think as you are finding out, you will have a tough time getting them to provide any relief when all they did is provided the fluid.

"I've yet to see a thread where someone actually split the pump and was able to reassemble it and have a functioning pump".

The key words here are "yet to see ...."

Well, successfully dis-assembling, cleaning up and re-assembling an AHC Pump has been posted time and again on the 100 series forum from the days of @PADDO onwards. It really is not difficult. More recent examples include contributions from @IndroCruise (ie multiple posts by me), others by @BullElk, also @Moridinbg, and a trail of others whom I cannot quickly remember.

Success depends on the internal condition of the Pump -- which in turn depends on the how well (or if!!) the AHC system has been maintained, including regular AHC Fluid change-outs per Owner's Manual -- or better still, twice as often. Very rare!

The link below is one of many examples with pictures. Yes -- it could be written up more definitively -- maybe one day I will get around to it -- because there are a few small but vital details which may trap the unwary. An explanation of the design, fluid flows inside the Pump, internal seal arrangements and how internal pressures are used within the pump to minimise bypass, and the purposes and reasons behind the Pump-related DTC's -- all would help understandings of this simple design, and why it varies from the standard approach to gear pump design, for example how this positive displacement gear pump survives without a pressure relief valve to prevent its destruction if overloaded.

AHC LX stopped working after globe change & possible air in system - https://forum.ih8mud.com/threads/ahc-lx-stopped-working-after-globe-change-possible-air-in-system.1306905/#post-14872072

The view sometimes offered that the strainers within the AHC Pump -- one at the Inlet and one at the Bypass -- and the similar strainer within the Return Valve immediately after the Pump discharge -- can be cleaned effectively WITHOUT splitting the Pump is the assertion of a fertile imagination. A little bit of low pressure back-wash by squirting fluid through the Pump does not cut it! Nor does reversing the motor polarity change the direction of fluid flow through the strainers and achieve a back-wash -- instead, if polarity and gear rotation are reversed, the fluid passes through the centre, between the gears, and not around the gear perimeter as it does in normal operation -- the fluid flow is in the same direction as in normal operation -- fluid is picked up at the Inlet and exits at the Discharge of the Pump.

However, all that said, if the above statement was re-framed to say,
"Is it worthwhile to split and repair a 17 years to 26 years old AHC Pump?",
my answer -- personal opinion only -- would be
"Been there, done that, not hard, made it work, so have others -- but no, I would not recommend it, nor would I use a second-hand Pump. Given the current Impex price of around USD100 for a new OEM AHC Pump (for LC100/LX470), why reinstate a twenty (?) years old high pressure gear pump?? The longevity and reliability of a new OEM replacement can so easily be included at low cost when the hydraulic circuit is disrupted during change-out of 'globes' on LC100/LX470."

 

[GremlinMobile]

To update everybody, I took the pump off and took it apart, including splitting the sandwich. I was careful not to rotate the two gears and especially not to change their orientation in relation to each other. It's tricky because when you first split the sandwich, the gears can come out depending on how you hold it, so you just have to move slowly and pay attention. I used a screw extractor to spin out both of the mesh filters, and blew carb cleaner through them. I ran the "new" AHC fluid with gel in it through coffee filters. Put everything back together, and filled the fluid back up into the reservoir. Took about 10 seconds or less for her to go from bottomed out LOW to N and then H. I'm back in business!

I was able to crack all four globe bleeders, but not yet the accumulator. I will bleed the globes once or twice next, and take her for a spin. Depending on how she feels, I might bleed some more, or not. I guess the next step to get it closer to perfect would be to follow the steps to check all the pressures and clearances - something I've never done before.

 

[suprarx7nut]

To update everybody, I took the pump off and took it apart, including splitting the sandwich. I was careful not to rotate the two gears and especially not to change their orientation in relation to each other. It's tricky because when you first split the sandwich, the gears can come out depending on how you hold it, so you just have to move slowly and pay attention. I used a screw extractor to spin out both of the mesh filters, and blew carb cleaner through them. I ran the "new" AHC fluid with gel in it through coffee filters. Put everything back together, and filled the fluid back up into the reservoir. Took about 10 seconds or less for her to go from bottomed out LOW to N and then H. I'm back in business!

I was able to crack all four globe bleeders, but not yet the accumulator. I will bleed the globes once or twice next, and take her for a spin. Depending on how she feels, I might bleed some more, or not. I guess the next step to get it closer to perfect would be to follow the steps to check all the pressures and clearances - something I've never done before.

SWEEEEEEEET!

Nice work. Simple pump, simple process.

Did you notice any debris or gel in the screens? Obvious that they were clogged?

 

[GremlinMobile]

SWEEEEEEEET!

Nice work. Simple pump, simple process.

Did you notice any debris or gel in the screens? Obvious that they were clogged?

Thanks. Yes the pump is impressively a simple device. Not a whole lot of parts. Good engineering. As soon as I opened it up, I found old hydraulic oil with black cloudy debris floating around in it, which is probably 21 years worth of steel particulates from the components and/or rubber seals deteriorating. The intake screen was full of gel from the defective fluid, which was the root of my issue.

I did 2 rounds of bleeding the globes. I still can't bleed the accumulator, so I haven't touched it. But it drives very smoothly, so logically, I should just leave it well enough alone. Of course my intrusive thoughts say to try to break that bleeder on the accumulator to do the job correctly...

 

[Hokie LX]

I was also going to chime in with some pictures from when I split my pump last year when I accidentally used fluid from plastic bottles (forgot) when changing my globes and my pump clogged up. Not difficult to split open, clean it out and reassemble. You do have to pay attention to the gear orientation on reassembly though. I reassembled mine incorrectly and was getting no fluid flow. I had the solid spacers flipped to the wrong side and reversed them and it's been working perfectly since October.

 

[IndroCruise]

I was also going to chime in with some pictures from when I split my pump last year when I accidentally used fluid from plastic bottles (forgot) when changing my globes and my pump clogged up. Not difficult to split open, clean it out and reassemble. You do have to pay attention to the gear orientation on reassembly though. I reassembled mine incorrectly and was getting no fluid flow. I had the solid spacers flipped to the wrong side and reversed them and it's been working perfectly since October.

View attachment 3625130

View attachment 3625131

View attachment 3625132

Here are a few more pics to add to the party -- and encourage basic "pump cleaning" if an existing pump is problematic or before a second-hand pump is fitted when pump renewal is not in the tea-leaves.

The point to ponder here is that sludge certainly will arise from new AHC Fluid which already is polluted with gel before it is added to the vehicle -- that much is well-understood by folks who have followed the "gel in 1 litre bottles" saga on IH8MUD on both the 100 series Forum and the 200 series Forum.

It may not be so well understood that this sludge can, and eventually will, build up in an AHC-equipped vehicle ANYWAY. Just give it enough TIME in the vehicle without bothering with the AHC Fluid change-outs recommended in the USA Owner's Manual at each 60,000 miles or 6 years (100,000 kilometres or 5 years in the Australian Owner's Manual). [If serious about hydraulic hygiene do this twice as often as recommended].

Once formed, the gel (or sludge) will sit around in the low-flow/slow-flow parts of the system.

The region around the AHC Pump sub-assembly covered by the end-cap is one of these, as seen in the above pictures ('borrowed' from various IH8MUD Members). It is also a low-pressure region.

The only time AHC Fluid flows in this region is when the fluid is returning from the system on its way back to the AHC Tank -- such as when the vehicle is self-levelling downwards or when driver changes height downwards from HI to N or from N to L.

Note: The returning AHC Fluid does NOT pass through actual gear pump on its way back to the AHC Tank; The Return Valve diverts the returning AHC Fluid to the AHC Tank through a direct connection -- there is nothing in between. The only pressure ever developed in this region is the flow pressure caused by the weight of the vehicle reducing its height. When the vehicle is at rest, the pressure in this region is the same as the pressure in the AHC Tank -- both are at atmospheric pressure!

So this region behind the AHC Pump cover (and the unswept volume of the 'shock absorbers' but that is another story) are the natural accumulation points for sludge, gel, products of oxidation or breakdown of aging fluid (which is a light mineral oil with additives) and other debris from wear and tear around the system.

Eventually, some of this stuff will be washed into the AHC Tank by the flow of returning AHC Fluid during normal operation of the vehicle. The AHC Pump then picks up the fluid -- but wait! Before it enters the AHC Pump it must pass through the small Inlet Strainer. This is the Strainer on the OUTSIDE of the body of the AHC Pump sub-assembly, marked with a star on the pic below.

This is the main location of pump Inlet blockage (and there are several DTC's to match). It is also the easiest strainer to extract -- the AHC Pump sub-assembly has to be removed from the vehicle but not necessarily disassembled. Removing and cleaning this strainer would be the MINIMUM thing to do before installing a second-hand AHC Pump sub-assembly -- but best to proceed and look inside.

In the good pics provided in the preceding post by @Hokie LX, another strainer can be seen. It is found INSIDE the AHC Pump when it is split open. This is not the Inlet Strainer. This is the Bypass Strainer.

In normal operation, the fluid is received on the Inlet side of the pump and sent by the gears around the perimeter of the pump (NOT through the middle of the gears where they mesh). That is, except for a very small amount of very high presure fluid which is trapped in the gaps between the meshing teeth as they complete each revolution and then face against the Inlet stream. For the pump to operate properly, this trapped fluid needs an exit pathway.

@GremlinMobile and @Hokie LX were meticulous in their disassembly and reassembly. If they were not, then on reassembly their pumps would not have worked properly if at all -- and they would be very unhappy.

They would have noticed the "notch" in one of the mating gear carriers as seen in the third pic by @Hokie LX . They would have ensured that this was positioned below the Bypass Strainer (and not fitted facing the other way -- which is possible but prevents the required release of trapped fluid) .

The "notch" allows the trapped fluid to escape away from the gears into the fine clearances around the gear carriers and into the region surrounded by the almost-triangular-shaped O-Ring -- see second picture by @Hokie LX. A "slot" can be seen in the area within the area of the almost-triangular-shaped O-Ring. It can be seen that then the two parts are mated (in the second picture by @Hokie LX), then there is a fluid passage to and through the Bypass Strainer, after which this fluid returns through the drillings in the Pump body to the Inlet side of the Pump.

The other benefit of this arrangement is that it loads pressure onto the gear carriers and the gears. This reduces the clearance the top and bottom planes of the gears and the pump body, reduces unwanted bypass and across the gears and reduces loss of performance. It is also the reason why it is worth having a good look below the gears and around the pump body for wear caused by the gears grinding away in dirty fluid!

All gear pumps, large industrial size, or small like the AHC Pump, have an arrangement with a similar purpose to release this trapped fluid, although designs vary a lot in the way this is done.

The one thing that is very different in the AHC Pump is the absence of a discharge pressure release arrangement to protect against pump destruction in overload. The point is that the pump is a positive displacement pump, meaning that if the pump is powered, then the fluid has to go somewhere. It is impossible for a gear pump to simply churn when there is a blockage at the discharge or downstream. Absent pressure relief in such situations, then when overloaded either the drive stalls until it burns out or its protection operates, or, the pump breaks. In the case of the AHC Pump, the protection is provided by the various DTC's acting together, rather than an arrangement for excess pressure to vent somewhere. This allows a very compact design.

Is it a "simple" pump?? "Elegant" might be a better word.

One further aside: There is a third strainer similar to those in the AHC Pump sub-assembly. This third strainer is located in Return Valve and is positioned to receive fluid discharged from the AHC Pump (but does not receive fluid returning from the system). Reports of blockages here are yet to be seen on IH8MUD -- or maybe it is just very difficult to diagnose.

 

[GremlinMobile]

Thanks for the great info @IndroCruise.

On another note, when I turkey basted the "new" gelled up AHC fluid from the reservoir, I saved it, and ran it all through a paper coffee filter. It looked perfectly pink and crystal clear as a result. That's the fluid that went back in. Should I be worried about this fluid gelling up again over time? Or was the gelling some kind of reaction the fluid had with the plastic bottles?

I guess I was lucky that the gelled fluid never made its way past the first mesh strainer inside the pump. Now that the fluid is all throughout my system, if it ever develops gel again, I'll be chasing the clumps of gel for a very long time..

 

[IndroCruise]

Thanks for the great info @IndroCruise.

On another note, when I turkey basted the "new" gelled up AHC fluid from the reservoir, I saved it, and ran it all through a paper coffee filter. It looked perfectly pink and crystal clear as a result. That's the fluid that went back in. Should I be worried about this fluid gelling up again over time? Or was the gelling some kind of reaction the fluid had with the plastic bottles?

I guess I was lucky that the gelled fluid never made its way past the first mesh strainer inside the pump. Now that the fluid is all throughout my system, if it ever develops gel again, I'll be chasing the clumps of gel for a very long time..

I don't know the answer to your two questions @GremlinMobile .

It is strange that this gel thing in fresh AHC Fluid seems only to have occurred in the 1 litre plastic bottles in the US market, and apparently was overcome with a return to the 2.5 litre steel cans.

-- Problem at the Idemitsu blending plant in USA?? (where it is likely the product was made),
OR
-- Problem with old stock?? (Seems unlikely when the recommendation is that the fluid can stay in the vehicle for up to six years),
OR
-- Problem with reactive packaging?? (No idea but surely some lab analysis would reveal]

Somebody knows but nobody is saying.

Will "reinfection" be experienced?? Don't know that either. Maybe yes if there is microbiological aspect of the problem -- something actually growing in the fluid?

What to do next??

If I had the problem, I would do the following:

-- use whatever consumer affairs agency is available to help me find some oil analysis outfit or other laboratory who are able analyse the gel,

-- sample the AHC Fluid in the AHC Tank, maybe every month for a while and visually inspect to see what develops, if anything, and act on any discovery of suspected gel with a comprehensive bleed and change-out with fresh new AHC Fluid,

-- after year, pull the pump and reinspect strainers -- then change the existing fluid anyway with fresh new AHC Fluid.

 

[Hokie LX]

I usually just flush my fluid every 2 years and I've owned my truck for 8 and haven't had any issues. Even my pump was pretty clean when I opened it up.

 

[gregdawg89]

Ever used an inductive bolt heater? Now might be your introduction, lol.

I recently got an induction heater and it works wonders on stuck and rusted fasteners. They come out with ease after that.

 

[GremlinMobile]

I don't know the answer to your two questions @GremlinMobile .

It is strange that this gel thing in fresh AHC Fluid seems only to have occurred in the 1 litre plastic bottles in the US market, and apparently was overcome with a return to the 2.5 litre steel cans.

-- Problem at the Idemitsu blending plant in USA?? (where it is likely the product was made),
OR
-- Problem with old stock?? (Seems unlikely when the recommendation is that the fluid can stay in the vehicle for up to six years),
OR
-- Problem with reactive packaging?? (No idea but surely some lab analysis would reveal]

Somebody knows but nobody is saying.

Will "reinfection" be experienced?? Don't know that either. Maybe yes if there is microbiological aspect of the problem -- something actually growing in the fluid?

What to do next??

If I had the problem, I would do the following:

-- use whatever consumer affairs agency is available to help me find some oil analysis outfit or other laboratory who are able analyse the gel,

-- sample the AHC Fluid in the AHC Tank, maybe every month for a while and visually inspect to see what develops, if anything, and act on any discovery of suspected gel with a comprehensive bleed and change-out with fresh new AHC Fluid,

-- after year, pull the pump and reinspect strainers -- then change the existing fluid anyway with fresh new AHC Fluid.

I noticed that my ride quality has deteriorated over the last several weeks since I cleaned the pump and put new fluid in. I went to bleed the globes last night and noticed that the fluid coming out of both rear globes appears to be an emulsion of oil and micro bubbles. It doesn't come out as a see-through oil like the fronts. Here is what I did:

1. Drained DS front globe. Clear fluid coming out. No bubbles.
2. Drained DS rear globe. Fluid with micro bubbles throughout. It didn't get any better no matter how much I drained. I didn't want it to get to the bump stops because I was worried there would be zero pressure and air would be introduced so I took about a cup or so of fluid out and closed the bleeder.
3. Poured new fluid into reservoir and started the engine. The pump ran and re-leveled the car. Turned engine off.
4. Went to drain PS front globe. Clear fluid coming out. No bubbles.
5. Went to drain PS rear globe. Extremely full of bubbles. Looked like a milkshake no matter how much I drained. Once it sat in a bottle for 10-15 mins, the fluid was clear.

Are the bubbles a function of cavitation or something in the pump or valves? I know people have perpetuated the theory of "failing globes" that leak nitrogen gas. But there's only so much of it. At some point, all the nitrogen gas will escape and be drained. I havent done too many bleeds so I'm wondering if this is part of the normal procedure and if I should keep draining and refilling or do I have an issue.

After the bleeding last night, the ride seemed maybe a little smoother. But if it's anything like last time, it'll probably get harsh again.

Thoughts?

 

[IndroCruise]

I noticed that my ride quality has deteriorated over the last several weeks since I cleaned the pump and put new fluid in. I went to bleed the globes last night and noticed that the fluid coming out of both rear globes appears to be an emulsion of oil and micro bubbles. It doesn't come out as a see-through oil like the fronts. Here is what I did:

1. Drained DS front globe. Clear fluid coming out. No bubbles.
2. Drained DS rear globe. Fluid with micro bubbles throughout. It didn't get any better no matter how much I drained. I didn't want it to get to the bump stops because I was worried there would be zero pressure and air would be introduced so I took about a cup or so of fluid out and closed the bleeder.
3. Poured new fluid into reservoir and started the engine. The pump ran and re-leveled the car. Turned engine off.
4. Went to drain PS front globe. Clear fluid coming out. No bubbles.
5. Went to drain PS rear globe. Extremely full of bubbles. Looked like a milkshake no matter how much I drained. Once it sat in a bottle for 10-15 mins, the fluid was clear.

Are the bubbles a function of cavitation or something in the pump or valves? I know people have perpetuated the theory of "failing globes" that leak nitrogen gas. But there's only so much of it. At some point, all the nitrogen gas will escape and be drained. I havent done too many bleeds so I'm wondering if this is part of the normal procedure and if I should keep draining and refilling or do I have an issue.

After the bleeding last night, the ride seemed maybe a little smoother. But if it's anything like last time, it'll probably get harsh again.

Thoughts?

If the AHC Pump was implicated, you would have seen the relevant Diagnostic Trouble Codes, particularly DTC C1762 and DTC C1751, and/or possibly others -- and would have experienced the accompanying "fail safe function" which prohibits AHC and TEMS operation -- meaning that the vehicle cannot be made to raise and the TEMS damping settings are fixed at the mid-point (step 8 of 16 steps) and there is no variable damping.

If the vehicle is raising as expected LO > N and N > HI in reasonable times, and if it appears that the Height Control Accumulator is being recharging as normal at the end of a raise, that would suggest that the AHC Pump is performing. If these responses are slow, then be suspicious of air or nitrogen in the system. Be aware also that "slowness" also can simply be the effect of a very heavy vehicle!

"Bubbles" mean gas in the hydraulic circuit -- either air (which is about 78% nitrogen, 21% oxygen and 1% other) or 'pure' nitrogen (close to 100%). Under pressure, either of these gases will be entrained and/or dissolved in the AHC Fluid and the fluid becomes "spongy". When the fluid escapes outside the system in the bleeder tube or container, it is suddenly released from AHC pressure, say 5 MPa to 7 MPa or more, to atmospheric pressure of about 0.1 Mpa. That is huge change pressure -- enough to trigger a change of phase and the gas emerges from the fluid as bubbles. This can take a while -- as observed when fluid is given time in a non-pressurised container.

This might just be air still in the circuit after the pump clean-out -- it can take a lot of persistent repetitive bleeding to clear the system after it has taken in the inevitable gutful of air which accompanies a disruption resulting from component change-outs. In particular, once air has found its way to that part of the 'shock absorbers' not swept by the piston -- it can wobble back and forth and take quite a few repetitions before the gassy fluid gives itself up and emerges from the fluid via the bleeder valve. Ditto the long pipes to the rear of the vehicle.

Sometimes it can help to force things along a bit by going to LO then starting the raise to N with the bleeder valve open (and tube attached) -- this can be messy and just be very careful that the fluid level in the AHC Tank does not drop too far and admit even more air into the system!

If your 'globes' are old, then your observations may be entirely consistent with the experience we all have when the 'globes' are in decline and nitrogen is leaking past or through a membrane -- it is a bit more than a "theory".

When at rest (and also in motion except when cornering at speed) the Rear Gate Valves (in the Control Valve Assembly) are open and the RH Rear and LH Rear 'globes' and 'shock absorbers' are hydraulicly connected. Ditto the Front Gate Valves. The Front and Reat AHC hydraulic circuits are not hydraulically connected.

The point here is that it can be diffcult to discern whether the problem is just one 'globe' -- or both Rear 'globes'. The reality is if one 'globe' is past its best, the others will not be far behind.

Sometimes the intensity of the "bubble stream" at one 'globe' may suggest that this 'globe' is problematic.

If not already done, suggest carry out the attached FSM test of overall 'globe' condition.

Yes --if failing 'globes' are the cause, then the rate of deterioration may increase and as a result you can expect that the ride harshness to occur more often.

And yes -- eventually 'globes' with failing membranes will have fluid going through the membrane and taking over the volume previously occupied by nitrogen. There is a lot of highly compressed nitrogen in there, displacement can take a while and usually occurs slowly but surely over the life of the 'globe', say 10 years but can be more or less.