LX470: how well will it "carry" an ARB?

[RoderickGI]

Or would they have such a problem with an owner doing this that they'd refuse to perform the service?

I know that the Lexus dealers I have used, and there have been about three, will only do maintenance work by the book.

Since the FSM specifies adjusting the pressures at the Normal position, I don't think a Lexus dealer will touch it. Unless they don't realise it is the High position, in which case they would adjust it incorrectly.

 

[hoser]

There is one Lexus dealer around here that will do it.

 

[AggiePhil]

I know that the Lexus dealers I have used, and there have been about three, will only do maintenance work by the book.

Since the FSM specifies adjusting the pressures at the Normal position, I don't think a Lexus dealer will touch it. Unless they don't realise it is the High position, in which case they would adjust it incorrectly.

So how else can you get the AHC and torsion bar s*** lined out properly if you want to roll with it in H mode all the time?

 

[RoderickGI]

So how else can you get the AHC and torsion bar **** lined out properly if you want to roll with it in H mode all the time?

As it is not designed to run that way by Lexus, you are on your own as far as they are concerned. I think that is fair enough. You can't expect them to investigate and design work arounds for any mod people do to their trucks.

If you can find a Lexus dealer who will do it, great. Otherwise you will need to find someone else willing to do it, or do it yourself.

Or you could get Slee to do it, or tell you how to; what the settings/pressures should be and so on. After all, you have installed a Slee mod, not a Lexus mod.

 

[AggiePhil]

Oh yeah, I understand that. So Slee is in Colorado. That's gonna be a no-go. Does anyone on this forum know how to do the procedure and what equipment is involved? This place could really benefit from a Tech Article reference area.

 

[hoser]

Manual way to do it....
https://forum.ih8mud.com/100-series-cruisers/457836-tool-adjusting-ahc-torsion-bar.html

Electronic way to do it...
Google "Mongoose J2534 Interface Toyota"

Be advised the specs are different depending on which method used to measure. Specs are in FSM.

 

[uHu]

This place could really benefit from a Tech Article reference area.

This is the Tech Article Place. That's why we post here. And the Neutral-Pressure-Adjustment procedure is in here.
Search is a friend, but she's not easy.

 

[joshuaesc]

I have had an ARB Sahara Bar and Warn HS9500 winch, plus dual batteries, compressor, snorkel and ARB diff locker on the front of my 1998 LX470 since 2003. I didn't adjust the Torsion Bars originally, as ARB didn't advise it, or think it necessary when I asked. It is necessary, and the truck rides much better since I adjusted the TBs to the correct settings.

I also have an ARB rear bumper with dual tyre carrier, a Longranger fuel tank, storage drawers, cargo barrier, radios, etc., on the rear half of the truck, so have fitted OME 862 springs on the rear to carry the extra weight. They are a little stiff, especially when the truck isn't loaded, but they are the correct height for a standard AHC installation.

I agree with just about all of the above advice with no issues, except that if you don't have an FSM and either the electronic or hydraulic equipment to set the AHC pressure correctly at the NORMAL setting, then take it to a dealer and have them adjust the Torsion Bars for you. Don't guess how many turns you need to add, or take advice on that here, since all bars are set differently to begin with, and wear differently.

Personally, while I understand the allure of larger tyres, I have taken my truck over every sort of terrain except real rock crawling, without the need for them. The same thing with a permanent lift. If I have to drive through deep water, I set the AHC to Hi and drive slowly enough that the AHC stays in high. That means I can drive through one metre deep water without a problem. If I have to get up, or down a big shelf on a track, AHC in Hi and away I go. Only really big shelves cause me concern.

If you really need a lift because you will be going rock crawling, or need larger tyres because you will be driving in deep mud a lot, then you had better add sliders to protect the side sills of the truck, and you probably should install a Slee front bumper, rather than the ARB.

I guess my query is: How serious are you about the off road work you will be doing, and do you really need a lift? If not, just add the front and rear bars, and maybe other stuff I mentioned above, and go out and enjoy!

Can you post several photos of your LX?

 

[Wilsil]

Roderick, what you describe is exactly what I want to do with my car.
Do you have any issues with the weight sensors with all this weight?
Only difference is I will be towing a Kimberley Kamper as well.

 

[RoderickGI]

Do you have any issues with the weight sensors with all this weight?

Do you mean the height sensors? The AHC simply measures the height of each front corner, and the rear axle, and pumps oil into the system, or releases some, until the correct height is achieved, with some exceptions.

If you mean the height sensors, no, I haven't had trouble with them.

If you mean pressure sensors within the system, the weight of the vehicle i still pretty close to the GVM, unless fully loaded, so I'm hoping that the pressure sensors, used for things like pump cut-off, oil return bypass and such, can cope with the extra pressure. That could be a misguided hope.

However, I did replace all four spheres because they had lost pressure and I had a bouncy plus hard ride. I used rechargable third party spheres with custom pressures in them, from Keith Bowers at Active Suspension Systems. I also adjusted the torsion bars to carry more weight. The rear springs had already been upgraded to carry extra weight. Which ones I used are in posts around here somewhere . . . ah yes, Old Man Emu (OME) 862 springs from ARB.

Anyway, the fix using new spheres lasted a few months, then the problem gradually returned for the front axle. The rear still seems to be fine. I haven't fixed that problem yet, with other things like life getting in the way, so I have a bouncy and hard ride at the front again. The spheres could have lost pressure, or it could be a problem with air/gas in the lines, which are a pain to bleed properly, especially from the hydraulic rams.

It could be a problem with the front actuators, such as worn or stuck valving, stuck or blocked return line, or god knows what. All I know is that I don't want to pay Lexus to fix it, since they just replace something until it works again, at great cost to the customer. So I have to find/make time to investigate properly, and potentially find somone to recharge my spheres.

So, if your real question was, "Does it all work with all that weight on it?" The answer is yes, for a while. Can it be maintained? Maybe, but I don't know as I don't know why it isn't working properly now.

I suspect that to really make it work with lots of extra weight on the LX, you should both increase the spring rates and increase the dampening. Because I can't really redesign/rebuild the Actuators, which do the dampening, the only way to increase dampening is to increase the viscosity of the oil use. I haven't looked into that yet.

Not much help really, am I? I guess if you do it, you take the risk that you will have the same problems as me in a few years.

Note that my suspension worked fine for over six years after I added all the weight, and I used the LX on some very serious 4WDing trips. So it isn't like the AHC fails under more weight immediately.

 

[Jim_Chow]

According to the FSM, you are supposed to adjust the t-bars if anything up front weighs more than some amount (I think it's like 40 lbs). IIRC, when I installed my sahara bar (winchbar, but no winch), with the mount bolted on, it sat at the same height as with the factory bumper/crash beam. The wing is maybe 60-70 lbs more? In the end, my front end was maybe 1/2" lower, but the AHC will take up the slack. Technically, you are supposed to crank the t-bars until the AHC pressure at each front shock falls in some range (it's in the FSM...too lazy to look it up for 'ya, plus you need the lexus tester). IIRC, you use the tester with the engine OFF but have to turn it on to allow the pressures at each shock adjust to the load of the sahara bar.

 

[RoderickGI]

Can you post several photos of your LX?

Hmmm, I thought I had a couple in my Profile Album, but there was nothing there. I added one there anyway.

For larger and more, see here

 

[RoderickGI]

According to the FSM, you are supposed to adjust the t-bars if anything up front weighs more than some amount (I think it's like 40 lbs).

That is about right, but I used hydraulic gauges attached to the bleed points to measure the pressure directly.

 

[Wilsil]

Thanks mate, I only notice that you are in Oz.
And close to Dazz or what his username is. He is on the LCOOL site and has a workshop in upgrading the AHC.
He is too far away from me (Perth)
I haven't done anything to my LX yet, but an ARB deluxe winch bullbar will be on it.

 

[Surfy]

I would not change something on the AHC System, when you want to have a good system.

It is designed, to be capable of everything. On road, Offroad, what you want. Put it in high, you get a bad milage on the highway.

When you have to quickly dodge on higher speed, you are in high - near a rollover. Thats why the car gets lower on higher speeds.

Too loose the ride comfort, is another issue.

 

[Alanywhere]

I have had an ARB Sahara Bar and Warn HS9500 winch, plus dual batteries, compressor, snorkel and ARB diff locker on the front of my 1998 LX470 since 2003. I didn't adjust the Torsion Bars originally, as ARB didn't advise it, or think it necessary when I asked. It is necessary, and the truck rides much better since I adjusted the TBs to the correct settings.

I also have an ARB rear bumper with dual tyre carrier, a Longranger fuel tank, storage drawers, cargo barrier, radios, etc., on the rear half of the truck, so have fitted OME 862 springs on the rear to carry the extra weight. They are a little stiff, especially when the truck isn't loaded, but they are the correct height for a standard AHC installation.

I agree with just about all of the above advice with no issues, except that if you don't have an FSM and either the electronic or hydraulic equipment to set the AHC pressure correctly at the NORMAL setting, then take it to a dealer and have them adjust the Torsion Bars for you. Don't guess how many turns you need to add, or take advice on that here, since all bars are set differently to begin with, and wear differently.

Personally, while I understand the allure of larger tyres, I have taken my truck over every sort of terrain except real rock crawling, without the need for them. The same thing with a permanent lift. If I have to drive through deep water, I set the AHC to Hi and drive slowly enough that the AHC stays in high. That means I can drive through one metre deep water without a problem. If I have to get up, or down a big shelf on a track, AHC in Hi and away I go. Only really big shelves cause me concern.

If you really need a lift because you will be going rock crawling, or need larger tyres because you will be driving in deep mud a lot, then you had better add sliders to protect the side sills of the truck, and you probably should install a Slee front bumper, rather than the ARB.

I guess my query is: How serious are you about the off road work you will be doing, and do you really need a lift? If not, just add the front and rear bars, and maybe other stuff I mentioned above, and go out and enjoy!

RoderickGI,

I liked your post and found it informative. I bought the LX because it had the AHC which allowed me to drive it as a daily driver 80% of the time and then use the AHC when I needed the height. My expereience is that the speed requirements are resonable and I wouldnt be going any faster in rough terrain anyway.

Out of curiosity, what size tires do you run. You seem to have a fair load on your turck and still manage to not hit ot rub (I assume here). I'm currently running 275/70's but was looking at moving to the 285's

 

[RoderickGI]

Out of curiosity, what size tires do you run. You seem to have a fair load on your turck and still manage to not hit ot rub (I assume here). I'm currently running 275/70's but was looking at moving to the 285's

I'm still running the standard size tyre. Specifically, the Silverstone AT-117 Special 275/70R16 114S. Look under the "More Info" tab. Actually I am back on the original rims and tyres at the moment, as I need to replace the Silverstones, probably with Coopers of some designation. I might consider 285's, but I would need to be sure. My brother runs 285's on his 100 series Landcruiser with no issue, as do many around here.

See https://forum.ih8mud.com/100-series...-tire-pressure-very-confused.html#post5722243 for some more information.

Unfortunately the AHC isn't working as well for me these days. Search around here and you will find some posts on the topic. Just another thing I need to fix. I've never had a problem with rubbing though, even fully loaded up at 3500 Kg. The AHC and springs I'm using, with tightened torsion bars, hold the weight no problem. The AHC just isn't dampening properly these days.

 

[joshuaesc]

I'm still running the standard size tyre. Specifically, the Silverstone AT-117 Special 275/70R16 114S. Look under the "More Info" tab. Actually I am back on the original rims and tyres at the moment, as I need to replace the Silverstones, probably with Coopers of some designation. I might consider 285's, but I would need to be sure. My brother runs 285's on his 100 series Landcruiser with no issue, as do many around here.

On my 99 LX I have 305 with no rub.

 

[Wilsil]

RoderickGI, your setup is exactly what I want to do with mine.
Good to read that everything was working well.
What is the problem now? The age of the system?
With the ARB bar on the only thing you did was adjusting the torsion bars? Did you just put the ride height back as it was before the bar?

 

[RoderickGI]

What is the problem now? The age of the system?
With the ARB bar on the only thing you did was adjusting the torsion bars? Did you just put the ride height back as it was before the bar?

The problem now is that I have a bouncy and hard ride, which are the symptoms of failed Actuator Spheres. That is, the spheres have lost their gas pressure, again. I replaced the OEM spheres with aftermarket ones a while back, and they worked fine for a while, but then the symptoms recurred. I don't really know exactly what the problem is now, and haven't had time or resources to investigate or fix it. So I bounce down the road for now.

I replaced the rear springs with OME aftermarket springs when I fitted all the heavy gear back in 2003, but didn't adjust the torsion bars until I replaced the OEM spheres, at which time I tightened them a lot, and then backed them off a bit to get the AHC to carry a bit more load and reduce the springiness of the ride. (The ride was good, but the suspension felt overly "keen".) The installer said they didn't adjust the torsion bars in 2003, and advised against it. Wrong.

The aftermarket spheres I bought had custom gas pressures to match my rear springs, weight, and expected torsion bar settings. The pressure was set lower than standard, in the expectation that I would be loading up the truck and hence the pressure would be normal when out travelling. This was probably a mistake. I should have gone for standard pressures to allow the Actuator to work corredctly, in its correct pressure range.

You live and learn. I can charge my aftermarket spheres to a higher pressure, which may fix my current problem, but I'm not sure. There could be air in the AHC lines, even though I have bled the things to death. Or the Actuator valves may no longer be working properly, maybe just because of the lower AHC pressure at normal height, or maybe because they are old.

I went for a lower pressure in the spheres partly because I wanted to match the front to the back, and I have the heavier OME springs in the rear all the time, so need less AHC pressure in the rear unless I am really loaded up. The rear sits up a little when I am unloaded.

If I was doing it all again now I would leave the AHC at standard pressures, put heavier torsion bars in the front, like standard non-AHC bars, and adjust them to carry the additional static weight in the front, leaving the AHC to carry the dynamic weight, and running at normal (standard) pressures.

In the rear I would leave the original springs, or maybe just slightly heavier springs, and install a supplementary set of Air Bag springs inside the original springs to carry the additional static and dynamic weight when the truck was loaded. Basically the bags would carry the additional static weight when unloaded using a low air pressure setting, and carry the dynamic load when the truck is loaded up using a higher air pressure. With this arrangement I could either have a variable air pressure controller in the cab, or air filling points on the rear bar. Either would work, since usually you don't need to change the airbag pressures on the fly.

As long as you don't exceed the AHC's maximum load carrying capacity, you only need to tweak the torsion bars up to carry the extra static load. In your case, the ARB Bullbar, winch, second battery, etc. if fitted. The stiffer non-AHC torsion bars would assist in carrying the extra weight when the suspension is articulating. The AHC will always adjust the truck to the correct height, without any need to adjust the torsion bars, by just adding more pressure into the system. The only reason you adjust the torsion bar when weight is added is to reduce the working pressure of the AHC back down to its normal range. Don't adjust the ride height sensors. Don't overtighten the torsion bars in an attempt to lift the vehicle. Get the FSM and read how to measure and adjust the AHC pressure at Normal height setting, which involves either electical voltage testing, or using pressure gauges. I used gauges.

Good luck.