AHC Globe Life Expectancy, Age or Mileage dependant? (1 Viewer)

[Snowrydr01]

Is there a conclusion on what the primary reason for AHC globe failures are?

Is it the charge seeping out of the rubber over time? Or is it the constant exercising that come with mileage?

Im looking at two car this weekend that are VERY different so the question is AHC specific.

One is an 02 LX470 with only 97k miles on it. The other is an 06 LC (with AHC) with 189k miles on it.

Neither show AHC service being performed. Assuming both are "ok" now, which would you put your money on going downhill first?

 

[Ramathorn15]

I think the common cause of acute failure is putting washer fluid in the reservoir. The alcohols/solvents eat through the membranes.

Chronic failure seems pretty rare but it's surely from not having the fluid changed and likely moisture build up in the fluid.

I'd trust either if it is functioning at time of purchase. Just change the fluid right away and keep driving.

A friend recently got a 2002 with 220k miles with no history of ahc service except for one when a shop put washer fluid in and the previous owner caught it and took it immediately to the dealer. His system still works flawlessly.

 

[planomateo]

Based on what I've read, it doesn't sound like dealerships provide servicing of the AHC fluid...which is odd to me. Maybe I misread some of the posts, the FSM had a bleed procedure, so you'd think this was something they'd offer as a service.

Contamination of fluid, lack of neutralization that could ultimately cause premature failure would be primary cause of failures based on what I've read. Replacing the fluid is super easy to do along with getting things in proper specs.

I have a LX with 160k and a LC with 114k, I've replaced fluid in both and dialed in to specs.

 

[flintknapper]

I wouldn't let the prospects of globe condition be the determining factor for which vehicle to buy. There are much more important things to consider. I.E. maintenance, overall condition of each, newer features (transmission)....etc.

You can replace the globes on either vehicle with Modified Citroen units for approximately $800.00 (if you install yourself) if you wish to retain the AHC system. Alternately....its possible to replace the AHC system with a conventional suspension (springs, shocks and TB's) for about 1K.

Personally, I'd be looking at the 2002 since it has 90,000 fewer miles on it. But again, maintenance can be a BIG factor. A higher mileage (but better serviced) vehicle can be the better value. But unless....abused or neglected, a vehicle with 'substantially fewer miles, will always garner more attention from me.

 

[DirtDawg]

It's the high pressures that kill the globes. So the short answer: both mileage and age affect this and improper maintenance. The rear springs lose their height and spring rate over time and with mileage resulting in higher neutral pressures. The front torsion Bars are the same, but can be adjusted.

 

[Ramathorn15]

It's the high pressures that kill the globes. So the short answer: both mileage and age affect this and improper maintenance. The rear springs lose their height and spring rate over time and with mileage resulting in higher neutral pressures. The front torsion Bars are the same, but can be adjusted.

Totally overlooked pressures. Definitely a big factor but is pretty easily cured.

 

[Snowrydr01]

It's the high pressures that kill the globes. So the short answer: both mileage and age affect this and improper maintenance. The rear springs lose their height and spring rate over time and with mileage resulting in higher neutral pressures. The front torsion Bars are the same, but can be adjusted.

Neither show a service history for adjustment so ones been potentially sitting at high pressure for 15 years but ones been potentially cycling more at high pressure.

Sounds like 6 of one half dozen of the other.

I guess it is all moot and comes down to my calibrated but and the all important rust factor of the northeast.

 

[trdcorolla]

My new to me 2001 LX with 95k miles (dealer maintained till 75k) failed the AHC grad test (5) but I still bought it. I did the 2 can AHC flush during my baselining. It has high Techstream pressures. Talked to @PADDO and i'm going to replace the rear springs and add a 30mm spacer and then adjust the TB's neutral pressure. I'm hoping that the new parts will get my pressures back to spec and maybe give me a few more notches on the grad test, we'll see.

 

[Snowrydr01]

My new to me 2001 LX with 95k miles (dealer maintained till 75k) failed the AHC grad test (5) but I still bought it. I did the 2 can AHC flush during my baselining. It has high Techstream pressures. Talked to @PADDO and i'm going to replace the rear springs and add a 30mm spacer and then adjust the TB's neutral pressure. I'm hoping that the new parts will get my pressures back to spec and maybe give me a few more notches on the grad test, we'll see.

That is kind of where i am leaning towards if i go with the older one since it is cheaper. Throw some fluid and spacers at it and adjust back into optimum range, then if its still not good then replace it with tough dog or iron man and not have that much invested. the 06 is at the absolute top of my budget so if its not functioning correct its not even on the options list since i wouldnt have funds to do anything about it.

 

[PADDO]

Is there a conclusion on what the primary reason for AHC globe failures are?

Is it the charge seeping out of the rubber over time? Or is it the constant exercising that come with mileage?

Im looking at two car this weekend that are VERY different so the question is AHC specific.

One is an 02 LX470 with only 97k miles on it. The other is an 06 LC (with AHC) with 189k miles on it.

Neither show AHC service being performed. Assuming both are "ok" now, which would you put your money on going downhill first?

By "globe failure" do you mean the relatively rare sudden, catastrophic rupturing of the diaphragm resulting in no damping/compressibility at that particular damper assembly or the gradual loss of the nitrogen pre charge due to gas permeance? If its the former then that may be caused by AHC fluid chemical contamination weakening the resin/rubber membrane and ultimately causing it to rupture or simply by mechanical failure due to a weakness in the membrane's matrix. I've had bladder accumulators burst in very high end, meticulously maintained systems for no obvious or apparent reason. If the latter then that's the normal phenomena of gas permeating across a physical barrier - the resin membrane - and time and temperature are the dominate driving forces and not so much the pressure differential. All accumulators with flexible bladders/diaphragms will loose pre charge. Industry norm is 5-10% per year in general applications. High neutral pressures will encourage fluid past "shock" actuator seals and cause visible weeping; aged fluid with depleted friction modifiers and reduced viscosity will exacerbate any weeping. My position would be there are too many variables and unknowns to say an '02@97k will be better/same/worse than an '06@180k. Best you can do is drive them, do the L to H test for a rough and general indication of the remaining net charges and buy the one that suits your needs and check book.