Show us some pictures (actuators (where the Globes screw onto), hydr. rams, front sensors)
AHC Bouncy & Stiff Front End
- Thread starter NorCalFJ100
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I'll get photos in the morning. The shop is about 45 minutes away plus traffic on a Friday. What are you thinking? I hate loosing the height control.
I'm thinking that we can tell if it's a goner or not by the pictures.
Lots of mechanics (masters included) just don't want to touch the system. Rust is the knock out punch though. The problem is, there's no "bypass". The fix is to install an aftermarket system or retrofit OEM conventional. Both those options are laborious and often more expensive than fixing AHC (the one exception being fatal rust).
Pics would help a ton.
Yes, curious what's rusty. Rusted lines mean game over usually. Other things like the dampers can probably handle some surface corrosion.
They suggest the system has an internal leak.
These components don't look to be in a very bad shape & IMO they're still useable. Do you have pictures of the struts and the height sensors?
This is it. The concern is the bleeder valve. Not sure I’m calling it the right thing. They worry it will snap. The concern is that there is an internal leak. Fluid is very low and no external leak was seen.
What I mean is no other photos.
As a comparison, this is how mine looked like when I had to decide to delete the AHC instead of trying to fix it. But my struts (rams) where rusted through and leaking and all 3 sensors where gone / hacked by PO.
Ah I see.. Well the bleeder nipples handle a lot (all 5 of mine came loose* - and they're replaceable if they round them off. Snapping them is a different story ofcourse, because for that to fix, the actuator would have to come off).
*I was not so lucky undoing the AHC lines from the actuators / struts - Those I had to cut off. And that is the real issue.. If the corrosion of the AHC system gets to the point that the actuators / struts are not removable without cutting the AHC lines, then it is not financially viable to repair the system.
I don't know what to say to be honest.. depends on how bad or good shape the other components are.. I would definitely give at least the bleed nipples a try & replacing the AHC fluid, setting neautral pressures & see how it acts after that before deciding on replacing the whole lot.. Best would be to take it to someone who has experience with fixing AHC issues, because lots of mechanics just don't like to deal with it. I also don't recommend DIY'ing on it if you're not 100% sure what you are doing, because it is easy to drop the truck on yourself (when undoing the nipples for example) & the pressure in the system is also not something to play around with.
One thing I can tell for sure, that going for a conventional suspension is a huge loss after one has got used to the plushness of the AHC. Even if you somehow manage to nail a good suspension configuration for your truck / driving style (which is very-very-very hard to achieve) it won't be half as good riding in it compared to the AHC. On the other hand, ~$2000 solves all your current and future issues - this is why I'm happy I did the replacement on mine afterall. Yes it rides bad, I hate how I can feel every little bump in my spine, but at least I know that the suspension will outlive the truck and I'll never have to put a single dime into it..
Let's see what others say.
@fotomon , there is very little rust on your ahc parts. There is no reason the bleeders would brake, unless they are, or have been, mistreated. Some penetrating spray on first, then use a 6 point socket to brake them loose.
Internal leak is not a thing - it shows only how much (little) the tech understands. (Most of them do not know the LC100 AHC/TEMS). If you combine the info that the fluid is low and that you have a very small difference in fluid level between Lo and Hi, the conclusion is that the globes are in need of replacement. The missing fluid is now in the globes, where you should have had nitrogen. That the fluid is dark could be an indication that someone has filled in the wrong fluid, unless it is actually 13 years old.
But you actually have to go through complete diagnostics, measure heights and get all the readings from ahc ecu. My guess is that you will need new globes, new rear springs and an adjustment of the front springs.
Internal leak is not a thing - it shows only how much (little) the tech understands. (Most of them do not know the LC100 AHC/TEMS). If you combine the info that the fluid is low and that you have a very small difference in fluid level between Lo and Hi, the conclusion is that the globes are in need of replacement. The missing fluid is now in the globes, where you should have had nitrogen. That the fluid is dark could be an indication that someone has filled in the wrong fluid, unless it is actually 13 years old.
But you actually have to go through complete diagnostics, measure heights and get all the readings from ahc ecu. My guess is that you will need new globes, new rear springs and an adjustment of the front springs.
In that case yes, a globe replacement and a fluid replacement is probably all what's needed to get it back on track.
Message/Reply from Tech:
And he may be correct.
If the nitrogen bulbs are ruptured and you continue working the AHC it would eventually burp out the gas and replace with the fluid in the bulbs.
I can assure you fluid can bypass the lower seals and eventually leak from the top.
Keep driving the way it is and it will get there.
You can try new nitrogen bulbs. But in my experience with that many miles you are putting a band aid on a very worn suspension.
Dollars and cents.
And he may be correct.
If the nitrogen bulbs are ruptured and you continue working the AHC it would eventually burp out the gas and replace with the fluid in the bulbs.
I can assure you fluid can bypass the lower seals and eventually leak from the top.
Keep driving the way it is and it will get there.
You can try new nitrogen bulbs. But in my experience with that many miles you are putting a band aid on a very worn suspension.
Dollars and cents.
I kind of agree with him. It really comes down to what shape the struts (including bushings) and sensors are in.
The bulbs/globes/spheres/accumulators/gas springs (the devil is known by many names) do not have a top from which they can leak, and no "lower seal" other than the o-ring preventing the fluid to leak out. They are sealed chambers with only one opening.
Even without knowing you ahc pressure, it looks like your globes are out of gas, which means that the nitrogen (which is the main ingredient in air) has leaked out through the membranes in the globes, making the fluid foamy, and eventually making its way up to the reservoir and merging with the atmosphere there. This happens eventually with all the ahc equipped cruisers.
When the globes are "flat", the car should not be driven (at speed), as it is no longer roadworthy. The movement of fluid in and out of the globes is what make it possible to dampen the suspension movement (shock absorber function). Without gas in the globes, there can be no movement of fluid and therefore you have no shock absorbers.
The suspension parts are normally worn on an old car lacking maintenance, but the ahc components normally last longer then other suspension components. The first parts to require replacement are normally bushings, ball joints and coil springs. The gas springs (globes) normally last longer than the coil springs, and the rams that look like shock absorbers last much longer than normal shock absorbers. But, if you don't change the coil springs in time, and tighten the torsion bars, you will put more and more load on the globes and shorten their life span.
That said, there are many parts of the ahc/tems system that need checking, and if you are not comfortable with maintaining an ahc equipped cruiser, it can be a daunting task. The common way of diagnosis at a dealer's workshop, is to change out parts until everything works, which can get expensive. You really need to get hold of TechStream or some other code reader / tester which is compatible. You can check the heights and pressures and from that find the state of your springs (the state of the globes does not affect the static pressures and the functioning of the height control). You can also check the state of your 3 height sensors and their linkages.
It is more expensive to maintain a cruiser with ahc than one with conventional suspension, mainly because of the diagnostics and lack of understanding of the system. But if you do it yourself, and can afford to spend time on it, it can be affordable. I do like the ahc, but if I was going to drive across Siberia, or Africa, I would think twice about going with ahc.
@fotomon Thanks for the pictures. I'm with @uHu on this. That is not a "Delete AHC" level of rust. That's somewhat on the rusty side of normal, but that would not make me give up on AHC.
It sounds like you need new globes. $1000-$1500 in parts and you should be in good (at least better) shape. If you buy new globes, find a bigger failure down the road, you can sell the globes rather easily and recoup [most] that cost. Lots of folks here show up in need of new globes and are always looking for a cheaper option than the brand new OEM cost. Lightly used with a verified purchase date should sell well.
I'm not sure what the mechanic is talking about in regards to the worn suspension. What's worn? The globes? The $3 O-rings? The $5 bushings? The $150 pump? The $300 rear springs? All the other suspension links that are worn on most 100's with or without AHC?
On high mile AHC cars, I'd be concerned with the pump, sensors and globes. The rams seem to last damn-near forever. The top O-ring seal is the common problem point and occasionally a shock will need outright replacement. The O-ring is very cheap and the shock is $300-400. Sensors are $300-400 if memory serves. There are 4 shocks and 3 sensors. It's extremely unlikely you'd need to replace more than one or two of each in the duration of a 5 year ownership.
Replacing with good conventional setup is maybe ~$3k if you're paying a shop, maybe more to cleanly delete AHC. That should buy globe replacement and new O-rings on the rams and maybe even a new pump with the associated labor. Replacing with conventional isn't going to save you much $$ right now, but it does minimize the variation in your potential future costs.
If it were me, I'd roll those dice and throw on some new globes (sourced from ebay or Partsouq) and a 30mm spacer for the rear (unless you plan on adding some weight, in which case get King Springs).
It sounds like you need new globes. $1000-$1500 in parts and you should be in good (at least better) shape. If you buy new globes, find a bigger failure down the road, you can sell the globes rather easily and recoup [most] that cost. Lots of folks here show up in need of new globes and are always looking for a cheaper option than the brand new OEM cost. Lightly used with a verified purchase date should sell well.
I'm not sure what the mechanic is talking about in regards to the worn suspension. What's worn? The globes? The $3 O-rings? The $5 bushings? The $150 pump? The $300 rear springs? All the other suspension links that are worn on most 100's with or without AHC?
On high mile AHC cars, I'd be concerned with the pump, sensors and globes. The rams seem to last damn-near forever. The top O-ring seal is the common problem point and occasionally a shock will need outright replacement. The O-ring is very cheap and the shock is $300-400. Sensors are $300-400 if memory serves. There are 4 shocks and 3 sensors. It's extremely unlikely you'd need to replace more than one or two of each in the duration of a 5 year ownership.
Replacing with good conventional setup is maybe ~$3k if you're paying a shop, maybe more to cleanly delete AHC. That should buy globe replacement and new O-rings on the rams and maybe even a new pump with the associated labor. Replacing with conventional isn't going to save you much $$ right now, but it does minimize the variation in your potential future costs.
If it were me, I'd roll those dice and throw on some new globes (sourced from ebay or Partsouq) and a 30mm spacer for the rear (unless you plan on adding some weight, in which case get King Springs).
- Thread starter
- #59
@geanes & @LndXrsr I was finally able to get some time to come troubleshoot this some more.
First, I remeasured my pressures using just the N-->L-->N method twice. Results were pretty identical. Front still seems to be a little low, but slightly higher than my first test. I will crank TB counterclockwise here in a bit and see how that helps.
Secondly, I did the graduation test. One thing that is odd and I am assuming I must have too much fluid is that when I was on L, the fluid line was way over the MAX line. I placed a piece of tape where the line was, so when I went to H, I could see the difference. My truck was parked on a level surface, but the fluid line was not level of course. I am attributing that to the unlevel front end. Measurements below.
ON LOW:
ON HIGH:
ON NEUTRAL:
Lastly, my measurements:
Driver Front = 18.75"
Passenger Front = 20"
Rear Both = 21.50"
I replaced my front globes a few months ago. The rears were replaced maybe 3-4 years / 20k miles ago.
First, I remeasured my pressures using just the N-->L-->N method twice. Results were pretty identical. Front still seems to be a little low, but slightly higher than my first test. I will crank TB counterclockwise here in a bit and see how that helps.
Secondly, I did the graduation test. One thing that is odd and I am assuming I must have too much fluid is that when I was on L, the fluid line was way over the MAX line. I placed a piece of tape where the line was, so when I went to H, I could see the difference. My truck was parked on a level surface, but the fluid line was not level of course. I am attributing that to the unlevel front end. Measurements below.
ON LOW:
ON HIGH:
ON NEUTRAL:
Lastly, my measurements:
Driver Front = 18.75"
Passenger Front = 20"
Rear Both = 21.50"
I replaced my front globes a few months ago. The rears were replaced maybe 3-4 years / 20k miles ago.
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Looks like you need to do a couple things then recheck:
1) Need to level the front end from side to side be turning the TBs opposite directions.
2) Then adjust your front sensors if needed to get front heights where you want them (OEM height 19.75")
3) Now check your pressures and adjust TBs in the same direction to get pressures where you want them.
4) Fluid level should be between max and min when in N. So siphon or bleed a bit out. You're going beyond the markings to read your L-->H graduations.
1) Need to level the front end from side to side be turning the TBs opposite directions.
2) Then adjust your front sensors if needed to get front heights where you want them (OEM height 19.75")
3) Now check your pressures and adjust TBs in the same direction to get pressures where you want them.
4) Fluid level should be between max and min when in N. So siphon or bleed a bit out. You're going beyond the markings to read your L-->H graduations.