I'm brand new to this, so forgive me for my lack of knowledge. I put new accumulators on my LX470. The extremely rough ride has returned. I am curious to know if the problem could be due to something other than the accumulators??? The vehicle will lower and raise itself using the AHC. Is it possible for the accumulators to be dead/flat and the AHC system to still have the ability to raise and lower in a normal amount of time? Considering switching to the a non-AHC setup, but want to have clarity about my real problem before deciding. Any insight is greatly appreciated. Thanks
AHC- Are my accumulators dead?
- Thread starter LXnovice
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try flushing and replacing your hydraulic fluid if you have never done it completely.....but depending on how long you did it there should not be a reason they would be bad again other than contamination.
many have had problems with them after a Lube Service at non LX shop....the highly skilled technicians mistake the Hydraulic Fluid reservoir and pump for the windshield washer reservoir and put in washer fluid...once it cycles into system it ruins everything and you never know until too late.
I pulled mine completely....lines, actuators, shocks, springs, resevoir, relays, etc......never looked back.
many have had problems with them after a Lube Service at non LX shop....the highly skilled technicians mistake the Hydraulic Fluid reservoir and pump for the windshield washer reservoir and put in washer fluid...once it cycles into system it ruins everything and you never know until too late.
I pulled mine completely....lines, actuators, shocks, springs, resevoir, relays, etc......never looked back.
- Thread starter
- #3
Thanks, Brock. I have totally flushed the system. Samples look clean. I am assuming that the accumulators could be bad and the vehicle would still be able to raise and lower properly when not in motion? It is literally so bouncy on the road that it is bordering on unsafe. Could there be any other parts that might be causing the rough ride? I have read that the pump quits functioning if certain things are/aren't happening. Again, I don't claim to know much about this. Thanks
uHu
Bridgeburner
If the accumulators collapse, everything still works, lower and raise, standing still or in motion (slowly, that is). Just that it becomes extremely bouncy.
If you see that the ahc fluid level goes down, without a leak, it means that the accumulators' membrane has given in, and it's filled with fluid, becoming hard and not having any "springy function" anymore.
You haven't said anything about how long the accumulators lasted, in miles or years. Have you ever checked the neutral pressure? - to see that the ahc is not overworked. The dealers/workshops will never do it unless you insist - they normally don't even know that it could or should be done either.
If the accumulators don't last long, the fluid probably contains something foreign, like brake fluid. To get it out you need to flush the shocks as well, by taking them off. A normal bleed/exchange will not remove all.
If you see that the ahc fluid level goes down, without a leak, it means that the accumulators' membrane has given in, and it's filled with fluid, becoming hard and not having any "springy function" anymore.
You haven't said anything about how long the accumulators lasted, in miles or years. Have you ever checked the neutral pressure? - to see that the ahc is not overworked. The dealers/workshops will never do it unless you insist - they normally don't even know that it could or should be done either.
If the accumulators don't last long, the fluid probably contains something foreign, like brake fluid. To get it out you need to flush the shocks as well, by taking them off. A normal bleed/exchange will not remove all.
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- Thread starter
- #5
uHu, Thanks for the help. My LX can go from L to H in about 8 or 10 seconds. I thought that this might be an indication that the accumulators were still good, but it sounds like I need to test if the level in the resevoir changes when going from H to L and visa versa. Thanks again for your help.
I read about AHC contamination on here and I was curious to see if anybody else had experienced contaminated AHC fluid straight out of the can from Toyota/Lexus?
Any thoughts on a Suncore conversion kit? My LX vertually never gets off the road. I have heard great things about an ARB kit with a diff drop, but I figured if the Suncore was sufficient for on-road driving, I might go that route given the cost difference.
I read about AHC contamination on here and I was curious to see if anybody else had experienced contaminated AHC fluid straight out of the can from Toyota/Lexus?
Any thoughts on a Suncore conversion kit? My LX vertually never gets off the road. I have heard great things about an ARB kit with a diff drop, but I figured if the Suncore was sufficient for on-road driving, I might go that route given the cost difference.
- Thread starter
- #6
Also, Who would you recommend to take it to in order to test the neutral pressure. Lexus??? They will probably bend me over even for something minor. I saw this on other threads and it sounds like it requires a specific computer/tool.
Bottom line:
1) check gradations on ahc reservoir going from L to H and see whether you get 7 or more. (for reference I've seen others say they got 12 gradations on new globes, personally I get 10 gradations on my 05 original accumulators). If you get <7 you know you have bad accumulators. You can also remove them and look for a ruptured membrane on the accumulator.
2) you should also check for any DTCs off the AHC system (OBD scanner will not show them). obviously techstream and handheld tester does this quickly/easily, but there are manual steps you can follow (they've been posted numerous times b/f).
Specific responses to your questions and comments are below.
Rough ride is a vague term - from your descriptions below it looks like you're having a bouncy ride and that would seem consistent with failed accumulators.
As uHu said, system will raise and lower just fine regardless of Accumulators failed or intact.
If the pump quit working your ride wouldn't raise and lower, so I think you can rule that out.
The FSM has a test for identifying failed accumulators: you measure the gradations on the AHC Reservoir from when going from L to H. In short, more than 7 gradations and you're good, 7 or less, you've got bad accumulator(s).
If you replaced your accumulators yourself, I believe you can simply look at them to see if the membrane is ruptured. If you replaced them and now had another failure (how soon after in miles/years) then something else must be wrong. Are you using OEM accumulators?
The time it takes is not an indicator of the accumulator's condition (if anything I think it's an indicator of the pump and/or motor's condition).
You have nothing to lose other than time by asking an indie or dealership how much they would charge for testing and adjusting neutral pressure. If they have no clue move on to the next mechanic/dealership. An alignment costs ~$170 at my Lex dealership - technically vehicle height adjustment and neutral pressure adjustment is part of that alignment. If you paid for an alignment I wouldn't assume they checked vehicle height and NP unless you talked to the mechanic ahead of time, and make sure to have them show you the readouts b/f and after.
To reiterate same info in many other threads there are only two ways to test neutral pressure:
1) with a hydraulic pressure gauge that can handle a few thousand psi with the correct fitting
2) with techstream or handheld tester
I know some folks have used pressure gauges successfully but I've never seen a post where someone could say exactly what fitting and gauge kit works.
I have purchased Tactrix Openport 2.0 cable and used it successfully with Techstream Lite to measure neutral pressure and get access to all the other techstream lite goodies. Cable was ~$200. I found it to be well worth the money since I can see everything for myself and use it for other toyota/lexus vehicles and use it for other settings and diagnostics on my vehicle. I look at it as a long term 'investment'. If you go that route pm me if you want some additional guidance on how to use.
I live in N. Va - if you're anywhere nearby I can check your NP for you, just pm me.
1) check gradations on ahc reservoir going from L to H and see whether you get 7 or more. (for reference I've seen others say they got 12 gradations on new globes, personally I get 10 gradations on my 05 original accumulators). If you get <7 you know you have bad accumulators. You can also remove them and look for a ruptured membrane on the accumulator.
2) you should also check for any DTCs off the AHC system (OBD scanner will not show them). obviously techstream and handheld tester does this quickly/easily, but there are manual steps you can follow (they've been posted numerous times b/f).
Specific responses to your questions and comments are below.
Rough ride is a vague term - from your descriptions below it looks like you're having a bouncy ride and that would seem consistent with failed accumulators.
As uHu said, system will raise and lower just fine regardless of Accumulators failed or intact.
If the pump quit working your ride wouldn't raise and lower, so I think you can rule that out.
The FSM has a test for identifying failed accumulators: you measure the gradations on the AHC Reservoir from when going from L to H. In short, more than 7 gradations and you're good, 7 or less, you've got bad accumulator(s).
If you replaced your accumulators yourself, I believe you can simply look at them to see if the membrane is ruptured. If you replaced them and now had another failure (how soon after in miles/years) then something else must be wrong. Are you using OEM accumulators?
The time it takes is not an indicator of the accumulator's condition (if anything I think it's an indicator of the pump and/or motor's condition).
You have nothing to lose other than time by asking an indie or dealership how much they would charge for testing and adjusting neutral pressure. If they have no clue move on to the next mechanic/dealership. An alignment costs ~$170 at my Lex dealership - technically vehicle height adjustment and neutral pressure adjustment is part of that alignment. If you paid for an alignment I wouldn't assume they checked vehicle height and NP unless you talked to the mechanic ahead of time, and make sure to have them show you the readouts b/f and after.
To reiterate same info in many other threads there are only two ways to test neutral pressure:
1) with a hydraulic pressure gauge that can handle a few thousand psi with the correct fitting
2) with techstream or handheld tester
I know some folks have used pressure gauges successfully but I've never seen a post where someone could say exactly what fitting and gauge kit works.
I have purchased Tactrix Openport 2.0 cable and used it successfully with Techstream Lite to measure neutral pressure and get access to all the other techstream lite goodies. Cable was ~$200. I found it to be well worth the money since I can see everything for myself and use it for other toyota/lexus vehicles and use it for other settings and diagnostics on my vehicle. I look at it as a long term 'investment'. If you go that route pm me if you want some additional guidance on how to use.
I live in N. Va - if you're anywhere nearby I can check your NP for you, just pm me.
- Thread starter
- #8
agaisin, thanks. Your post was very helpful. I just checked to see how many gradations the level in the resevoir changed when lowering from the H to L position. It was only 3. I think that answers my question. Would you recommend checking the neutral pressure still, or is that irrelevant? To answer your question, I replaced the original accumulators with ones from B and B suspension in July 2010. I put roughly 10k miles on it since then, but the ride is worse than ever. Thanks again for the help.
Wow - sux. Your ride height is to spec, right (as far as you know)?
Anyhow, sounds safe to say that one or more of your accumulators are blown. If I were you I'd want to figure out why your accumulators keep failing before I consider getting a new set(faulty globes, contaminated fluid, extreme lift or weight in the vehicle?).
Let me ask another question - why did you replace the first set of accumulators and after how many miles on them?
If you decide to keep your AHC suspension DEFINITELY get the neutral pressure adjusted as part of the install (part of that process is setting vehicle height correctly first).
- Thread starter
- #10
Yeah. I think it is probably just time for me to switch to a non-AHC setup. I ran the original globes until 155k+/-. I am sure that it was not due to overloading. Haven't hauled anything since putting the new globes on. Any recommendations on the best kit (Old Man Emu, stock LC, Suncore, etc.)? Thanks for your help.
Man ... B&B blew after 10k? I'd think it's worth getting them replaced under his 'warranty' unless you're that deadset on replacing. 150k on the originals aint shabby!
As far as non-ahc options, there are other threads on the topic but I think you need to ask yourself what you are looking for in your suspension - lift or comfort or just non-ahc?
OEM (stock LC's shocks, springs, torsion bars), Bilstein, OME all seem to be popular options. Plenty of threads on the pros cons of them all.
If you're looking for the most comfortable ride I think functional AHC is your best bet with OEM coming in second. Bilstein and OME are both stiffer then OEM.
I've seen people rag on the OMEs for quality (blown shocks) but can't remember seeing anything negative about the Bilsteins. Can't remember anyone talking about Suncore at all. Seems like there are a lot of happy Bilstein users.
Fwiw, just what i can remember seeing. Search is definitely your friend
I had a similar issue and after I replaced the front, driver side height sensor, the problem went away. The sensor would not allow the truck to change height from the "N" position. The ride is now silky smooth. I have NO idea why that sensor would make a difference but it did.
I love the AHC and for our family use of your LX, I'll repair it when it fails.
I love the AHC and for our family use of your LX, I'll repair it when it fails.
FWIW, i have a similar sensor problem. I.e. My driver's side height sensor and the pressure sensor are both throwing codes intermittently and the ride is harsh in front. Every so often the "off" light will flash for a few hours or day. Just finished the 120k service and the mechanic tells me the globes are fine (plausible; the PO changed them at 80k).
Sensors are a 10 minute job although not exactly cheap.
Maybe the AHC sensors should be considered a maintenance item around 120k-140k like the oxygen sensors? I am right at 120k and had to replace the rear sensor a few months back.
BTW: the sensors can be persuaded to go a bit longer (months) if you disassemble, clean (electrical contact cleaner) and bend the little contact fingers down a bit.
Agaisin i am also in NoVa (Reston). I wouldn't mind a tutorial on the Techstream/Tactrix setup if you have time some weekend.
J
Sensors are a 10 minute job although not exactly cheap.
Maybe the AHC sensors should be considered a maintenance item around 120k-140k like the oxygen sensors? I am right at 120k and had to replace the rear sensor a few months back.
BTW: the sensors can be persuaded to go a bit longer (months) if you disassemble, clean (electrical contact cleaner) and bend the little contact fingers down a bit.
Agaisin i am also in NoVa (Reston). I wouldn't mind a tutorial on the Techstream/Tactrix setup if you have time some weekend.
J
Hi Brett, I know this is an old post but I was wondering how you knew you had a bad height sensor? Did your truck throw a code? I hear that the off light will flash if the sensor is bad. I'm about to pull the trigger on a set of new globes but might try a new sensor if that might solve my problem. thanks
uHu
Bridgeburner
Height sensors and globes have no influence on each other. If only the globes are shot, the height adjustment will still work just fine. You can read all about the AHC system here on mud, and easily find out from the different test if it is the sensors or globes which are faulty.
Thank you Brett, I appreciate it.
