LX470 Globes passed the pencil test, but my ride is aweful (1 Viewer)

[LanghorneLX]

Hi All!

I have had my LX470 for 6 years and I had all 4 accumulators replaced when I first purchased it with 120,000 mi. It now has 175K miles and the car has gotten bouncy really quickly like almost instantly I noticed a big difference. I drove up a high curb and rolled off at each of the 4 corners and I found that the rear SLAMMED to the ground and the front had no drama. So I ordered some 500cc rear accumulators from a Japanese "OEM" source and was ready to change them. I check and there was ~10 levels between the hi and lo setting. Also note, I proactivly change the AHC fluid ~6months ago and it had 14 level difference then. Any it rode great after the service.

Today I put the car on jack stands, drained the AHC fluid from the bleed screws in the rear, and I removed the rear accumulators. Note, I did not put it in lo first, my bad! During the service I found that quite a bit of fluid from the first side (drivers) that I drained and almost no fluid from the passenger side. I would say .25L from the drivers and like .05L from the passenger. Also the globes were NOT all foamy and the depth check (pencil check) was almost exactly the same as the new units. This was not what I was expecting. I pushed a metal punch into the globes to check that they have pressure and they seemed ok to me (180lb guy pushing down on them and they didn't budge). I was hoping that maybe I just reversed the pressure in the globed by jacking up the car prior to the service - Like I "sucked" the diaphram back to the neutral position, but that was not the case.

I am hesitant to put new units on because I can't return them if I do and I would think if they are holding N gas then they are ok. I just put the old globes back on and bled the system some and am scratching me head. I am wondering if the lack of fluid that drained from the passenger side is indicating a blockage or other issue?

I am open to ideas guys! Thanks for any help. Is there an expert you can recommend I direct message?

 

[suprarx7nut]

The system is linked side to side so when you released the fluid from the first side, that removed nearly all pressure from the other. That all makes sense and is generally how bleeding or fluid changes work with AHC. The first side releases more fluid. The second releases almost none.

Gradations: New globes are somewhere around 14. Completely dead and flat is around 4. That's 10 grads for 4 globes. Therefore, each has roughly 2.5 grads. If you went from 14 to 10, that's enough change to have 1 totally dead globe and 1 near death... Or perhaps 2 partially deflated.

The globes start at a very high pressure. I forget exactly what it is, but I recall something like 500psi+. The globe could be mostly dead and you'd still have a hell of a time manually depressing it. If it's totally ruptured, the pencil test will show that. If it's just a little low on pressure, I don't think you'd be able to tell.

The globes are a wear item. They are intended to be replaced. I would slap on the new ones. If it doesn't fix it then perhaps you have an actuator that's seized or something, but that's rather rare. Worn out globes are very common and they tend to last 50-150k miles and somewhere around 10 years. Their lifespan is akin to normal shocks. Eventually they'll completely fail and it will be obvious, but their performance will wane long before total catastrophic failure.

 

[IndroCruise]

Hi All!

I have had my LX470 for 6 years and I had all 4 accumulators replaced when I first purchased it with 120,000 mi. It now has 175K miles and the car has gotten bouncy really quickly like almost instantly I noticed a big difference. I drove up a high curb and rolled off at each of the 4 corners and I found that the rear SLAMMED to the ground and the front had no drama. So I ordered some 500cc rear accumulators from a Japanese "OEM" source and was ready to change them. I check and there was ~10 levels between the hi and lo setting. Also note, I proactivly change the AHC fluid ~6months ago and it had 14 level difference then. Any it rode great after the service.

Today I put the car on jack stands, drained the AHC fluid from the bleed screws in the rear, and I removed the rear accumulators. Note, I did not put it in lo first, my bad! During the service I found that quite a bit of fluid from the first side (drivers) that I drained and almost no fluid from the passenger side. I would say .25L from the drivers and like .05L from the passenger. Also the globes were NOT all foamy and the depth check (pencil check) was almost exactly the same as the new units. This was not what I was expecting. I pushed a metal punch into the globes to check that they have pressure and they seemed ok to me (180lb guy pushing down on them and they didn't budge). I was hoping that maybe I just reversed the pressure in the globed by jacking up the car prior to the service - Like I "sucked" the diaphram back to the neutral position, but that was not the case.

I am hesitant to put new units on because I can't return them if I do and I would think if they are holding N gas then they are ok. I just put the old globes back on and bled the system some and am scratching me head. I am wondering if the lack of fluid that drained from the passenger side is indicating a blockage or other issue?

I am open to ideas guys! Thanks for any help. Is there an expert you can recommend I direct message?

@suprarx7nut has explained accurately and succinctly as always. If more detail would help -- especially on why the so-called "pencil test" tells almost nothing useful about 'globe' condition unless they are completely destroyed -- suggest have a wander through the long explanations and pictures at Post #276 and Post#278 at this link:

The ABCs of AHC - How to Measure, Flush, and Adjust all in one place

On the topic of AHC fluid, I'm dropping my data point: I replaced all 4 factory globes a week ago and did the initial flush before globe R&R with 2.5 1L bottles that were bought Jan 2021 batches E8736 and E8737. The fluid sat in my garage for a year so I filtered them with 2 layers of coffee...

forum.ih8mud.com

 

[LanghorneLX]

Thanks for the explanation @suprarx7nut and follow up @IndroCruise !

I installed new rear globes and bled (following the instructions provided) with new fluid from a 1.5L metal can I got at the dealer yesterday. The 6month old fluid was very dark and the new stuff was pink. No bubbles in the old fluid. The car drives the same. Very bouncy - I am not happy with it. I drove off a curb and its dramatic af with the rear wheels (individually) and not the front wheels. I rank from lo to hi and it have 14 graduations. I also did notice that when I was initially cycling from lo to hi it "released" with a thud and jerk but after I exercised it it stopped doing that. I checked all my bushings and I don't see anything that looks off, just signs of 178K miles (rubber cracked, but not metal to metal or large tears in the bushings).

For a moment there I thought maybe it was stuck in SPORT mode. So I drove the car at 2mph and slam the brakes in SPORT mode - it's very dramatic and when in comfort mode its much less dramatic. So I think that is working. I already drive in comfort - my perference.

Any ideas?

I will go through YOTAMDs checklist and adjust the ht sensors and torsion bars, but there is something wrong with the rear suspension IMO. I even checked for a cracked spring in the back. I might get new springs, once I figure out how to get the software. I am sure at 178K it needs new springs.

One thing I will add is that I tow a 6x12' enclosed trailer with two motorcycles 1500mi/year. It has a high tounge load but I have never had an error code with the AHS or anything.

Thanks all!

 

[suprarx7nut]

Thanks for the explanation @suprarx7nut and follow up @IndroCruise !

I installed new rear globes and bled (following the instructions provided) with new fluid from a 1.5L metal can I got at the dealer yesterday. The 6month old fluid was very dark and the new stuff was pink. No bubbles in the old fluid. The car drives the same. Very bouncy - I am not happy with it. I drove off a curb and its dramatic af with the rear wheels (individually) and not the front wheels. I rank from lo to hi and it have 14 graduations. I also did notice that when I was initially cycling from lo to hi it "released" with a thud and jerk but after I exercised it it stopped doing that. I checked all my bushings and I don't see anything that looks off, just signs of 178K miles (rubber cracked, but not metal to metal or large tears in the bushings).

For a moment there I thought maybe it was stuck in SPORT mode. So I drove the car at 2mph and slam the brakes in SPORT mode - it's very dramatic and when in comfort mode its much less dramatic. So I think that is working. I already drive in comfort - my perference.

Any ideas?

I will go through YOTAMDs checklist and adjust the ht sensors and torsion bars, but there is something wrong with the rear suspension IMO. I even checked for a cracked spring in the back. I might get new springs, once I figure out how to get the software. I am sure at 178K it needs new springs.

One thing I will add is that I tow a 6x12' enclosed trailer with two motorcycles 1500mi/year. It has a high tounge load but I have never had an error code with the AHS or anything.

Thanks all!

I wonder what your neutral pressures are. Perhaps they're just way too high.

Pictures might be good. Do you have air bags in there?

 

[LanghorneLX]

I am following instruction on this forum to get XP and TIS installed.

Also no airbags, but I was gonna consider helper bags for when I tow but wanted to check pressures and then get new springs and bags at the same time. Open to suggestions there, but I think i need pressures first.

 

[FxFormat]

Rear being slammed leads me to believe the rear height sensor might be faulty, they can be had for cheap on here, look for people selling them. Worth a shot.

 

[jOnathN]

If you have too much AHC lift dialed in it will behave like that:
1) bouncy, because too much load is being carried on the globes alone, and
2) hard bang/thump dropping off a curb or ledge as the already-extended suspension runs out of travel.

 

[LanghorneLX]

Rear being slammed leads me to believe the rear height sensor might be faulty, they can be had for cheap on here, look for people selling them. Worth a shot.

I like that idea. I think that the pressure will be high when measured. That may be caused by the ht sensor issue. correct?

Also I wonder if I can test my sensor with a multimeter? OR perhaps there is a techstream test for the sensor?

If you have too much AHC lift dialed in it will behave like that:
1) bouncy, because too much load is being carried on the globes alone, and
2) hard bang/thump dropping off a curb or ledge as the already-extended suspension runs out of travel.

Thanks guys! Can I just adjust that out with the heim fitting on the rear height sensor? I took the sensor off and added dielectric grease on the connector and the gold springs.

 

[IndroCruise]

I like that idea. I think that the pressure will be high when measured. That may be caused by the ht sensor issue. correct?

Also I wonder if I can test my sensor with a multimeter? OR perhaps there is a techstream test for the sensor?

Thanks guys! Can I just adjust that out with the heim fitting on the rear height sensor? I took the sensor off and added dielectric grease on the connector and the gold springs.

If the Rear Height Control Sensor is in good condition inside, meaning no corrosion or moisture 'tracks', good clean connections at top and bottom of the spring connectors, brushes making good contact on the carbon track, and especially no visible wear points on the carbon track (usually occurs around the mid-point of the swing), then it is worth testing the Sensor. Inspection of the carbon track and brush contact is not enough -- makes no more sense than trying spot a fault by eye in an old Long Play record, may be visible, but may be not. Testing is essential. There are two testing possibilities:

• per attached extract from the FSM using a multimeter and 3 x 1.5 volt batteries, or at least,

• checking for smooth changes in resistance through the Sensor swing – along the lines suggested by @PADDO at Post #2 in this thread: High as a kite, hard as a rock! (Yes AHC again...) - https://forum.ih8mud.com/threads/high-as-a-kite-hard-as-a-rock-yes-ahc-again.1119157/#post-12149330

The practical realities are that the Height Control Sensors are 'wear item' and eventually will have to be replaced. When required, suggest use only Toyota/Lexus or AISIN Sensors - for reliability avoid others and avoid second-hand

Suggest also measure and feed back details of Front and Rear heights to give an idea of suspension travel in response to @jOnathN -- compared to stock hub-to-fender tape-measurements which are approximately 19.75 inches (or 500millimetres) at Front both sides, and, 20.50 inches (or 520 millimetres) at the Rear both sides.

Unless you have a non-standard link on your Rear Height Control Sensor (?), there should be no heim double-ended adjusting bolt on the Rear Sensor -- the adjuster moves in simple slider as shown in the pic below -- move it up to increase vehicle height (which also increases Rear AHC pressure), move it down to reduce vehicle height (which also reduces Rear AHC pressure).

As mentioned by @suprarx7nut, it is important to check actual Front and Rear AHC pressures, otherwise you are flying blind -- if either too high or too low at Front or Rear, then there will be poor damping at Front or Rear and 'bouncy' or 'springy' performance at Front or Rear is inevitable.

It is a wild long-shot guess way down the list of likely causes rather than good diagnosis (because there is insufficient information), but you may wish to check the response of the Damping Force Control Actuators (to which the 'globes' are attached) for each wheel using the "Damping Force Controlling Condition Check" (also called the 16 Step Test). This is described in Section 4 at page 5 of the last attachment (use an unbent paperclip or some other bridging wire rather than bothering with a Toyota/Lexus SST 09483-18020 connector -- which is a simple bridging wire anyway). The idea is to try to identify any stuck Actuators -- unusual but possible and certainly would affect damping performance.

Extracts from the FSM DIagnostic section for the Height Control Sensors and the Damping Force Control Actuators are attached. These explain the "fail safe functions" for both items and set out the symptoms which can be recognised in vehicle behaviour. Test methods also are described for each circuit.

Also suggest be suspicious of results of fluid displacement at the AHC Tank measured by graduations at "LO" and "HI" heights UNLESS this test as been done per the attached FSM extract with AHC pressures within the FSM-specified ranges. Otherwise the results are not comparable with FSM numbers.

Some of the information in Post #7 at the link below may be helpful:

Factory AHC Sensor Position

Had one of my Volvo techs put new upper control arms in my 05 LX, he didn’t note the position of the front sensor heim in the slotted boss on the old arm prior to removal. He placed the sensor all the way at the bottom of the slot on the new arms, which locked out the high setting and rode like...

forum.ih8mud.com

 

[LanghorneLX]

Hi gang!

I did get Techstream on a winXP emulator and got my pressures also made a little jig to mount to the hub center caps to take fender measurements.

First off and likely most importantly, I have the following two trouble codes: C1721 Damping force Control Actuator FR Circuit and C1723 Damping force Control Actuator FR Circuit. I saw the thread about the exhaust leak and shorted wires. I will go look for that, but it seems hard AF to fix. I am game for splicing, but is there a fast way to tell me to check what to pin out? I see all the diagrams, but I don't even know what the actuator looks like or where the AHC ECU is located.

When I disconnect my AHC reservoir heater the AHC system deactivates. Its and 06 LX. I was disconnecting to get better pressures as YotoMD recommended.

My measurements are as follows:

FL = 19-3/8"
FR = 19-15/16"
RL = 21-7/8"
RR = 22-7/16"

N position:
FR Sensor = 0.1
FL Sensor = -0.5
RR (rear?) Sensor = 0.1

Front = 4.0 Mpa
Rear = 8.3 Mpa
Accumulator = 10.6 Mpa

What should I try next other than look for burnt and shorted wires?

Thanks all!!!

 

[BullElk]

I just replaced all four globes on one of my '00 Lexii. The ride was rather bouncy more in the front than rear as I recall. 45 minutes of work and now it rides like new and raises and lowers perfectly.

I noticed lots of gas in the first front globe I bled. The others had very little of anything drain out. I also noticed the front two globes still had fluid in them I poured out but the rear globes did not. Would that indicate the diaphrams ruptured or wore enough to allow fluid to stay behind it inside the globe? If so, perhaps the rear globes still have life in them and are worth saving. ??

Fluid from reservoir

Fluid from just one front globe.