Need advice - keep AHC or AHC delete? (1 Viewer)

[Congo]

07 LX @ 170k miles. My AHC original shocks are weeping/rusted, but globe accumulators and AHC heigh control works fine. I know most have gone with AHC delete to normal shocks when the AHC breaks, but I really like the suspension. Need some advice whether I should do a direct stock AHC shock replacement or go with non-AHC shocks? I do not want a lift, factory height is just fine.

Is this the smart way to go for longevity? how long do stock AHC shocks last? I perhaps may be willing to delete AHC for a sportier ride if there's such shocks out there

Also, when under load and turning, I hear popping - so probably need to replace ball joints or something else too right?

 

[GTV]

If you look in your owners manual you'll see where weeping AHC shocks are addressed. They weep because over time your coil springs and torsion bars fatigue so the hydraulic system raises pressures to maintain ride height. Correct the pressures and they'll stop weeping.

 

[SkidMarcus]

My truck rode great with AHC...until it didn't. I was 10 miles in the woods when one corner decided to ride the bump stop (after cycling the key and letting it rest for a while, it started to act right). Another time I was in the mountains and another corner decided to be higher than the others (again, started acting right eventually). I enjoy my regular suspension as it doesn't rely on a 20 year old computer and parts, and can diagnose without a computer.

 

[Rhetoric]

My truck rode great with AHC...until it didn't. I was 10 miles in the woods when one corner decided to ride the bump stop (after cycling the key and letting it rest for a while, it started to act right). Another time I was in the mountains and another corner decided to be higher than the others (again, started acting right eventually). I enjoy my regular suspension as it doesn't rely on a 20 year old computer and parts, and can diagnose without a computer.

Did you perform all the maintenance on your AHC before going off road?

I am sure you did, but just wanted to check.

For what can be spent on new super awesome rides rough as a chuck wagon suspension you could do globes, sensors, and fluid before trekking into the finest expanses of God’s country. Heck, you could even put some new hydraulic rams (shocks) in there, too!

I have to chuckle every time the AHC bad mouthing starts. Find me another dynamic hydraulic suspension that can last 20+ years without a soul touching it. A static suspension would be shot well before then.

 

[2001LC]

07 LX @ 170k miles. My AHC original shocks are weeping/rusted, but globe accumulators and AHC heigh control works fine. I know most have gone with AHC delete to normal shocks when the AHC breaks, but I really like the suspension. Need some advice whether I should do a direct stock AHC shock replacement or go with non-AHC shocks? I do not want a lift, factory height is just fine.

Is this the smart way to go for longevity? how long do stock AHC shocks last? I perhaps may be willing to delete AHC for a sportier ride if there's such shocks out there

Also, when under load and turning, I hear popping - so probably need to replace ball joints or something else too right?

Those with a properly tuned AHC system, love it. They'll not give it up. Even some that build a heavy off road rig, keep AHC. AHC does have weight/load limits. But even load limit can be increased greatly. I helped set up one at shock height, that is very heavy. i.e. iron bumpers, swing out, sliders, roof rack, winch, cooler, 4 big hunters, their gear and dogs. It handles & rides great. It is also set up; So if a failure of AHC was to happen. It will not go down to the bump stops/rocks.

AHC shocks "weeping" is only a concern, if dripping wet. Rust may be a concern, but likely just outer sleeve. The AHC shocks last forever, if properly flushed and adjusted. AHC shocks, are actually more like hydraulic rams, than shocks. It's the 4 globes that need replacing over time. Which are gas chambers. Over time, the gas depletes from the globes, and sometimes the rubber membrane within, ruptures releasing the gas. All 4 globes will eventual need replacing.

But understand it is a more expensive system to maintain. If you've a rust bucket, the AHC hydraulic hard line, may also rupture. So evaluating your rig & intended use, helps make the decision to keep AHC or not.

Popping under load and turning. Can be a few different thinks. You need your rig properly inspected.
Just to some parts to consider:
Loose shocks mounts.
Loose wheel bearings.
Loose or bad TRE (inner or outer)
Bad ball joints.
Bad front drive shafts (AKA: FDS. AKA: CV's) or it's snap rings (inner or outer).
Rack & pinion mounts.
Control Arm bushing loose, damaged or worn out (upper and or lower)
Sway bars, and their: links bracket, bushings & cushions.

 

[suprarx7nut]

07 LX @ 170k miles. My AHC original shocks are weeping/rusted, but globe accumulators and AHC heigh control works fine. I know most have gone with AHC delete to normal shocks when the AHC breaks, but I really like the suspension. Need some advice whether I should do a direct stock AHC shock replacement or go with non-AHC shocks? I do not want a lift, factory height is just fine.

Is this the smart way to go for longevity? how long do stock AHC shocks last? I perhaps may be willing to delete AHC for a sportier ride if there's such shocks out there

Also, when under load and turning, I hear popping - so probably need to replace ball joints or something else too right?

AHC delete makes sense if the car is badly rusted underneath or if you don't understand AND don't want to learn the simple procedures to keep it very reliable.

AHC shocks *usually* last forever. Weeping is perfectly normal and likely means your system needs a quick and free pressure adjustment via torsion bars. The "shock" component of AHC is actually the "globe" that's remote mounted. That part wears roughly at the same time intervals as regular shocks and is far easier to replace than regular shocks. Costs about the same.

Height sensors can fail, but many last beyond 250k miles. Mine have so far. They more commonly fail from hitting violent potholes or rusting away, but they can also just wear out internally at the contacts.

Keep AHC.

 

[Kabanstva]

My truck rode great with AHC...until it didn't. I was 10 miles in the woods when one corner decided to ride the bump stop (after cycling the key and letting it rest for a while, it started to act right). Another time I was in the mountains and another corner decided to be higher than the others (again, started acting right eventually). I enjoy my regular suspension as it doesn't rely on a 20 year old computer and parts, and can diagnose without a computer.

same

 

[thibaut]

I had the same issue with corrosion on the dampners. They aren’t expensive from partsouq or equivalent.
I am a big fan of AHC as I do only very occasional off road and the comfort is hard to beat. Properly maintained the AHC is very reliable.

 

[PlutoBound]

I’m going to highjack if you don‘t mind as I’m in a similar decision point… I have a 2000 LX470 with about 300k miles on it. AHC has worked great up until now but then the left side sensor failed a few weeks ago. I replaced that but when I went to test the system I could not get any pressure and it is resting on the bump stops now. As part of trying to diagnosing\because I was there I went to flush the AHC fluid and have now sheared off the nipple off the accumulator. I have the records from new (all Lexus service before I purchased a few years ago) and although the system has been flushed I worry as I begin to replace parts i will have more issues with shearing/breaking lines etc just because of the age and it will turn into a never ending process. I’m leaning towards AHC delete now but love the ahc system.

 

[Skruf]

I’m going to highjack if you don‘t mind as I’m in a similar decision point… I have a 2000 LX470 with about 300k miles on it. AHC has worked great up until now but then the left side sensor failed a few weeks ago. I replaced that but when I went to test the system I could not get any pressure and it is resting on the bump stops now. As part of trying to diagnosing\because I was there I went to flush the AHC fluid and have now sheared off the nipple off the accumulator. I have the records from new (all Lexus service before I purchased a few years ago) and although the system has been flushed I worry as I begin to replace parts i will have more issues with shearing/breaking lines etc just because of the age and it will turn into a never ending process. I’m leaning towards AHC delete now but love the ahc system.

Forum wisdom is that unless your system is super corroded you're better off keeping it. Basically for the same price as an Ironman conventional set up you can go right through the AHC system and refurbish it and be left with a system that is far superior and with less compromises. I've just been though what you have been through. I put all new sensors in it and a new pump sub assembly. I'll go onto do the globes in time. Take the time to learn about it, it seems daunting but its actually not that complicated and theres heaps of resources here to point you in the right direction

 

[PlutoBound]

Forum wisdom is that unless your system is super corroded you're better off keeping it. Basically for the same price as an Ironman conventional set up you can go right through the AHC system and refurbish it and be left with a system that is far superior and with less compromises. I've just been though what you have been through. I put all new sensors in it and a new pump sub assembly. I'll go onto do the globes in time. Take the time to learn about it, it seems daunting but its actually not that complicated and theres heaps of resources here to point you in the right direction

Thanks! I appreciate the information.

 

[SilverKast]

I'm about to start going through the basics on my AHC system. I got the vehicle over the winter and just haven't had the chance to work on it until now so I'm going to go through the AHC thread and hopefully work my way slowly around. I really like the system, it's pretty cool being able to adjust the height with it. Mine currently "sorta" works. It goes into L, N or H but it won't stay in High. Once I start driving over about 25 km/h it just goes back to N. I'm hoping some basic maintenance will fix everything but it is a little overwhelming at first seeing the volume of info we have available.

 

[SteveH]

@SilverKast Once I start driving over about 25 km/h it just goes back to N.

That's normal - at 19 MPH, the system will not let itself run in 'high' and reverts to normal. If you have the truck in 'low' and exceed 8 mph, it will revert to normal. Read your owner's manual....and I think there's even a sticker somewhere in the vehicle that says this.

 

[GTV]

I'm about to start going through the basics on my AHC system. I got the vehicle over the winter and just haven't had the chance to work on it until now so I'm going to go through the AHC thread and hopefully work my way slowly around. I really like the system, it's pretty cool being able to adjust the height with it. Mine currently "sorta" works. It goes into L, N or H but it won't stay in High. Once I start driving over about 25 km/h it just goes back to N. I'm hoping some basic maintenance will fix everything but it is a little overwhelming at first seeing the volume of info we have available.

@SteveH nailed it. First step to AHC is to read your manual so you understand how it was designed to work. It will operate in low up to 10km/h, then raises to neutral. It will stay in high until 30km/h then lowers to neutral.

 

[Skruf]

Unless you're in low range then it stays in high regardless of speed

 

[SilverKast]

@SilverKast Once I start driving over about 25 km/h it just goes back to N.

That's normal - at 19 MPH, the system will not let itself run in 'high' and reverts to normal. If you have the truck in 'low' and exceed 8 mph, it will revert to normal. Read your owner's manual....and I think there's even a sticker somewhere in the vehicle that says this.

Did not know that, thanks! The previous owner did not provide a number of items that would have been useful - owners manual being one of them. Also no factory tool kit, which made for all sorts of fun getting the full sized spare out he had put in.

 

[suprarx7nut]

I’m going to highjack if you don‘t mind as I’m in a similar decision point… I have a 2000 LX470 with about 300k miles on it. AHC has worked great up until now but then the left side sensor failed a few weeks ago. I replaced that but when I went to test the system I could not get any pressure and it is resting on the bump stops now. As part of trying to diagnosing\because I was there I went to flush the AHC fluid and have now sheared off the nipple off the accumulator. I have the records from new (all Lexus service before I purchased a few years ago) and although the system has been flushed I worry as I begin to replace parts i will have more issues with shearing/breaking lines etc just because of the age and it will turn into a never ending process. I’m leaning towards AHC delete now but love the ahc system.

Did you replace with genuine Toyota sensor? Aftermarket sensors are 100% garbage and should be expected to fail immediately (literally immediately - many users share stories of the aftermarkets ones not working at all brand new).

A couple sheared nipples are a piece of cake compared to an entire suspension swap. Just refurb AHC as needed. Pervasive rust is a problem. Normal surface corrosion and a sheared nipple is fine.

same

Every time you share that I think it needs an asterisk: *because I never did the free and fast pressure check and T-bar adjustment.

 

[Zjohnsonua]

Keep it. Jam some air bags in the springs if the time comes that you need more load capacity and want to de-leverage the hydraulic system.

 

[PlutoBound]

Did you replace with genuine Toyota sensor? Aftermarket sensors are 100% garbage and should be expected to fail immediately (literally immediately - many users share stories of the aftermarkets ones not working at all brand new).

A couple sheared nipples are a piece of cake compared to an entire suspension swap. Just refurb AHC as needed. Pervasive rust is a problem. Normal surface corrosion and a sheared nipple is fine.




Every time you share that I think it needs an asterisk: *because I never did the free and fast pressure check and T-bar adjustment.

Luckily no rust. It is an ASIN sensor but did not come in a Toyota box [but from Rock Auto]. I'll go that route first and see if it fixes the glitch outside of the wayward nipple.

 

[Jfcol]

Just the fact that owners with AHC have coined the term “pogo sticking” reminds me how happy I am that my 05LC came with primitive suspension! I’m sure I don’t know what I’m missing but I love the ride from my medium duty OME springs and stock shocks. I’m also happy with my ride height regardless of speed and terrain.