AHC Accumulator or old fluid / B&B vs toyota (1 Viewer)

[4FLATS]

All,
I have a 1999 LX 470 that seems to have a problem with the front suspension. Super stiff, from what I have read this is one of 2 things, Bad fluid (wishfull thinking) or Bad accumulators.
I posted on another board and got sent to B&B for their replacemnent system. I spoke with Keith and he seemed to know his stuff. Then somone said that the ih8mud folks said not to use him. I serched and didn't find any negitive posts other than his shipping boxes aren't pretty. I don't want to pick a fight or get everyone ralled up I just want to know what works at the best price.

Can anyone share your thoughts on this part vs factory?

 

[4FLATS]

Still searching for anything neg about B&B / Keith. Why would someone send me here to find how mad everyone is if I can't find it?

I know it is strange for a guy with 1 post to be asking a question like this but I got to pull the trigger on factory or B&B parts.

 

[hoser]

I have no experience with B&B and cannot say anything good nor bad about them but just looking at the two offerings, this is how I understand it:

B&B $700/pr front accumulators (plus $250 per unit core charge)
OEM roughly $900/pr through one of several of our mud vendors (no core charge, afaik)

Warranty on OEM is 1 year. Warranty on B&B is one year full, then prorated up till 3 years. But prorated means if failed after 2 years, then they will only cover 33% of the cost.

The fact is both OEM and B&B have and will fail/wear down eventually. After you replace the front two, the rear will go sometime in the future and you'll be down $1500-1800.

If you don't want to worry about it, switch to OEM or OME suspension now and you'll have saved in the long run. I think fixing the accumulators would be worth it if your LX was just a few years old but it's not.

Or search the classifieds here and pick up Land Cruiser OEM T-bars and springs for maybe $100. Buy some new bilsteins for $250 or so and a few hundred bucks on labor or do it yourself.

 

[4FLATS]

I have no experience with B&B and cannot say anything good nor bad about them but just looking at the two offerings, this is how I understand it:

B&B $700/pr front accumulators (plus $250 per unit core charge)
OEM roughly $900/pr through one of several of our mud vendors (no core charge, afaik)

Warranty on OEM is 1 year. Warranty on B&B is one year full, then prorated up till 3 years. But prorated means if failed after 2 years, then they will only cover 33% of the cost.

The fact is both OEM and B&B have and will fail/wear down eventually. After you replace the front two, the rear will go sometime in the future and you'll be down $1500-1800.

If you don't want to worry about it, switch to OEM or OME suspension now and you'll have saved in the long run. I think fixing the accumulators would be worth it if your LX was just a few years old but it's not.

Or search the classifieds here and pick up Land Cruiser OEM T-bars and springs for maybe $100. Buy some new bilsteins for $250 or so and a few hundred bucks on labor or do it yourself.

Thanks for the reply, 900 is quite a bit less than the local dealer will sell them to me.

I do hate the AHC when hooking up the boat trailer. It is really a pain. Do you know of anyone that has had sucess with with LC stock swap? This truck is 99% Grocery-Getter and baby wagon and I pull the 9,000lb (I know it is over weight) boat 2 blocks at 10mph every weekend.

Would the LC susp handle that? How is the highway response? My wife isn't the most attentive driver with 2 kids going nuts in the back seats.

 

[pman]

There are several members that have gone to regular LC suspension on their LX. There is nothing you need to worry about as far parts working or damaging anything, the suspension on the LC/LX are identical except for the shocks/springs.

As for the boat, LC springs will be very soft for that kind of weight. You may want to consider getting airbags or going to some stiffer OME springs. Honestly though you should be considering a Tundra to pull that kind of weight, but your not going far or fast.

Alot of people on here prefer the ride/handling of traditional suspension over AHC, but that is more personal preference. In your situation, removing AHC will not negatively affect the highway handling unless you do something wrong.

 

[4FLATS]

There are several members that have gone to regular LC suspension on their LX. There is nothing you need to worry about as far parts working or damaging anything, the suspension on the LC/LX are identical except for the shocks/springs.

As for the boat, LC springs will be very soft for that kind of weight. You may want to consider getting airbags or going to some stiffer OME springs. Honestly though you should be considering a Tundra to pull that kind of weight, but your not going far or fast.

Alot of people on here prefer the ride/handling of traditional suspension over AHC, but that is more personal preference. In your situation, removing AHC will not negatively affect the highway handling unless you do something wrong.

Using the adjustable suspension as a guide, would you say the LC stuff would be like the softest setting on the dial? Or worse? What about something from Eibach / Bilstine (I haven't had to spell that since I was a kid)

Will my check engine light go nuts? I need it as some family members don't keep an eye on the gauge cluster...

Honestly if I am going to tow my boat further than down the block to the ramp I borrow a full size truck.

 

[pman]

The LC shocks/springs are somewhere near the middle of the LX's ride settings. However, the LX will compensate for extra weight using the hydraulics, standard LC springs will not be able to do that.

Check engine lights wont be a problem

 

[4FLATS]

Thanks for all the info, It is just kind a hard to say good by to all that fancy suspension....

I found several after market kits that use the stock torson arms and add a coil over along with new all new springs and shocks in the rear.

If my main concern is highway safety for my wife and kids. (pulling the boat is low on the list) am I barking up the wrong tree? Is the factory setup better?

 

[Brock]

i would think that any towing, offroading, or loaded trips would be much better off with aftermarket OME suspension upgrade....the stock had a soft mushy feel with a lot of body roll on all LC I drove....I like my AHC better in my LX. When it leaks or starts having issues I am going to OME or Ironman suspensions for overall stability, wide range of uses, and still having a domesticated feel on highway that is not overly rough.

I would get their medium setup and never look back if in your shoes.

 

[pman]

Going to standard shocks and springs, whether they are from Toyota or some other company, will not adversely affect safety unless you put on the overly stiff or soft stuff.

Do you have link to the add a coil kit you mentioned.

IMO you should go with Toyota or OME t-bars/ springs and some Bilstein shocks. Do that as a baseline, if you feel that it is way to soft for towing your boat, just add some airbags in the rear or change to stiffer aftermarket springs.

I'm a bit lost on your question regarding safety concerns. When you say factory setup, are you asking if keeping AHC is safer than going to traditional suspensions. Or do you mean going to factory LandCruiser shocks/springs is safer than aftermarket shocks/springs?

.........either way, any reasonable setup is not going to be more or less safe than another

 

[RoderickGI]

I must one of the few here that will be keeping my AHC, I suspect. I have made some changes though, since I have increased the kerb weight from ~2525 Kg to 3180 Kg. I replaced the rear springs with OME 862's, and tightened up the standard LX torsion bars so that the AHC wasn't runnning higher pressures than it was designed for. In fact, my AHC now runs at lower than standard pressures.

I installed four B&B Actuator Spheres when my rears failed, and my fronts were on the way out, at less than half the cost of OEM spheres, plus shipping America to Australia. They seem to be doing the job fine, although the ride isn't like it was when the LX was new, since I have a lot of extra gear and weight on it. I found Keith extremely helpful, providing advice and pre-charging the spheres to a pressure I agreed to, in addition to sending them over to Australia promptly. As Keith doesn't recharge OEM units any more, there is no Core charge involved in the transaction. Just the price on his web page (US$1,400), plus shipping. I would buy from Keith again.

If I was doing the rear springs again, I would definitely consider putting air bags in instead of the 862's, so that I got a better ride when I wasn't carrying a load in the back. As it is, my suspension is firmer than standard, but quite acceptable.

The reason Lexus claim it isn't safe to replace the AHC with standard suspension is that the AHC does have some anti-roll functionality built in. If the steering wheel is turned beyond a certain amount, and the outside of the vehicle is lower than the inside when cornering, as measured by the front sensors, the AHC can lift the outside body, reducing body roll and the potential for rollover. As I understand it, this is achieved because the front oil circuit is common to both wheels normally, but each side works independently once the steering wheel is turned beyond a certain point. What real value that is as compared to aftermarket suspension is up for debate.

If you like the AHC, buy a couple of spheres from Keith (or a set of four), flush the system properly, and maybe put some adjustable air bags in the back to support the springs when you are towing.

 

[Tinkerer]

<snip>

The reason Lexus claim it isn't safe to replace the AHC with standard suspension is that the AHC does have some anti-roll functionality built in. If the steering wheel is turned beyond a certain amount, and the outside of the vehicle is lower than the inside when cornering, as measured by the front sensors, the AHC can lift the outside body, reducing body roll and the potential for rollover. As I understand it, this is achieved because the front oil circuit is common to both wheels normally, but each side works independently once the steering wheel is turned beyond a certain point. What real value that is as compared to aftermarket suspension is up for debate.

<snip>

Can anyone post a link to info on c.1999 LX470 AHC roll control details?

I saw something on this in Service Manual or etc., but all it said is that when steering wheel is turned more than 30 degrees, the left and right side are decoupled to allow better roll control, or something like that. (And inside steering wheel assy, there is a thin disc and sensor assy that does have cutouts at about +/- 30 degrees, evidently for this purpose.)

What I'm wondering is whether the AHC roll control provision is limited to simply decoupling left and right side in a tighter turn, or whether there is also some active roll control such as changing pressure or damping on one side or the other in a turn. I don't think it could increase pressure fast enough to help, although it might decrease pressure and change damping rapidly enough to make a difference.

 

[Brock]

stiffer OME suspension reduces body roll on turns as well...makes it handle more like a slot racer. Had my FJC loaded with hundreds of pounds on roof rack and with OME Heavy/Heavy springs and their long travel shocks...never felt awkward or unsafe.

I think you will be more than pleased with the OME and Bilstein setup...getting Medium springs for rear, OME Tbars and the Bilstein shocks....even the OME are nice.

 

[uHu]

Can anyone post a link to info on c.1999 LX470 AHC roll control details?

I saw something on this in Service Manual or etc., but all it said is that when steering wheel is turned more than 30 degrees, the left and right side are decoupled to allow better roll control, or something like that. (And inside steering wheel assy, there is a thin disc and sensor assy that does have cutouts at about +/- 30 degrees, evidently for this purpose.)

What I'm wondering is whether the AHC roll control provision is limited to simply decoupling left and right side in a tighter turn, or whether there is also some active roll control such as changing pressure or damping on one side or the other in a turn. I don't think it could increase pressure fast enough to help, although it might decrease pressure and change damping rapidly enough to make a difference.

As I understand it, it is only passive roll, pitch & squat control. I.e. the dampers are tightened up to maximum on the outside wheels in a curve, or on the front wheels when braking.
See attached.

 

[RoderickGI]

Can anyone post a link to info on c.1999 LX470 AHC roll control details?

I don't have one I'm afraid.

What I'm wondering is whether the AHC roll control provision is limited to simply decoupling left and right side in a tighter turn, or whether there is also some active roll control such as changing pressure or damping on one side or the other in a turn.

I assume that once the left and right sides are decoupled, the ECU will try to adjust each side to the correct height according to the sensors. I guess this would be constrained by any damping change actions it was taking as well.

This is why it makes sense to have the AHC Height Adjustment off button in the truck. If you are wheeling with only two wheels on the ground, and your steering wheel turned in a finely balanced attempt to negotiate large rocks, and not tip over, you do not want the AHC to cut in and try to lift the weight bearing side of the body. That could result it a roll over.

I don't think it could increase pressure fast enough to help, although it might decrease pressure and change damping rapidly enough to make a difference.

Don't forget that the AHC includes a reservoir of high pressure oil in the Accumulator, which can supply small quantities of oil for fast changes in height. The pump is required for larger changes, and to charge the Accumulator, of course. Also, I don't recall the numbers, but the AHC ECU makes adjustments to the damping force through the Actuator very fast. It calculates what is required something like 1000 times a second, and has something like 16 damping force positions. Again I have to assume that the switching is fast, so the damping force changes are fast.

 

[pman]

I don't have one I'm afraid.

I assume that once the left and right sides are decoupled, the ECU will try to adjust each side to the correct height according to the sensors. I guess this would be constrained by any damping change actions it was taking as well.

This is why it makes sense to have the AHC Height Adjustment off button in the truck. If you are wheeling with only two wheels on the ground, and your steering wheel turned in a finely balanced attempt to negotiate large rocks, and not tip over, you do not want the AHC to cut in and try to lift the weight bearing side of the body. That could result it a roll over.

Don't forget that the AHC includes a reservoir of high pressure oil in the Accumulator, which can supply small quantities of oil for fast changes in height. The pump is required for larger changes, and to charge the Accumulator, of course. Also, I don't recall the numbers, but the AHC ECU makes adjustments to the damping force through the Actuator very fast. It calculates what is required something like 1000 times a second, and has something like 16 damping force positions. Again I have to assume that the switching is fast, so the damping force changes are fast.

Dude, if thats true, then I have seriously been underestimating the powers of AHC on the 100.

 

[RoderickGI]

Well, some of it is educated guessing, and I don't have a reference for it. But it could be right.

An instructor on a 4WD course I did many years ago used my LX to demonstrate the effect of diff locks when balancing on two wheels. Basically he drove over an arrangement with humps staggered so that the LX was on two wheels, with two in the air. At the time he turned off the AHC because he said it would try to level the vehicle when on two wheels, and lift the body at the two supporting wheels.

I can't say I have conclusively proven that the AHC will lift the corner suspension, which is compressed when it is balancing on two wheels, but it definitely works the AHC hard trying to do something when in that situation. I usually just don't stay balanced long enough, or have an external observer, to test it.

The Accumulator definitely works as I described.

 

[uHu]

At the time he turned off the AHC because he said it would try to level the vehicle when on two wheels, and lift the body at the two supporting wheels.
I can't say I have conclusively proven that the AHC will lift the corner suspension, which is compressed when it is balancing on two wheels, but it definitely works the AHC hard trying to do something when in that situation.

This is why it makes sense to have the AHC Height Adjustment off button in the truck. If you are wheeling with only two wheels on the ground, and your steering wheel turned in a finely balanced attempt to negotiate large rocks, and not tip over, you do not want the AHC to cut in and try to lift the weight bearing side of the body. That could result it a roll over.

As far as I have observed, the AHC automatically turns off when negotiating large rocks or bumps. Try changing the height when the wheels are at different heights. Nothing happens, which can be quite frustrating.
But yes, generally it works pretty well.

 

[uHu]

Although we are getting a bit away from the original issue her, - for a bit of further reading on the issue:
* See page DI-211 for which input signals the AHC ECU has;
* page DI-221, Symptom #2, Suspect Area #2 for "Inhibiting conditions";
* page SA-338 for how to check the gas springs (aka spheres, aka nitrogen chambers), (which is more in line with the original post of this thread)

 

[4FLATS]

Wow, thanks for all the info. As this is my wife's baby buggy 99% of the time. I think I might replace the accumlatiors and fluid and let her run it for a few more years. When I see a good deal on a replacement system I am going to grab it and put in in the garage (aka car hole) for a rainy day when the whole system takes a crap. Then it will me my truck with the suspension I want

Question, can anyone point me to the best place to order these online?