LS - 3rd Gen (2001-2006) Discussion topics related to the flagship Lexus LS430

HELP - Switched from air to steel suspension

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Old 02-23-18, 01:02 PM
  #16  
garcea
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I’ve a 2004 UK market LS430 fitted with the dreaded air suspension. It’s now 14 years old with 79,000 miles from new - with a full main Lexus dealer service history but so far the air suspension seems fine. The car is in great condition, I’ve only owned it for just over a year but want to keep it until something terminal and unaffordable to fix happens to it. Hopefully that eventuality is years away as I just love the car!

I’ve been gradually working through small maintenance issues with it such as broken AC compressor (replaced along with a leaking condenser radiator ), broken brake pad wear wiring harnesses- also replaced - new radiator as original was looking past its best and new Toyota coolant.

The timing belt was replaced 3 years ago at 54,000 miles by a Lexus main dealer but the water pump is original.

Other stuff done is new PCV fitted, throttle body cleaned along with air mass meter, new Denso Iridium OE spark plugs fitted, air filter, engine oil and oil filter (with oil flush), brake fluid change and new front Lexus rotor pads fitted.

Transmission had 4 ATF drain and refills using Toyota WS fluid plus a new transmission filter fitted, plus a bottle of Lubeguard Red ATF additive used on the final fill. A separate ATF cooler was fitted which bypasses the original (and potentially unreliable!) ATF to coolant heat exchanger. Gear changes perfect - smooth and quiet.

The car is running great, but with its ago I’m thinking that the rubber air strut bladders are on borrowed time and won’t last much longer. So, my plan is to gradually accumulate all the parts needed to ‘convert’ from air to conventional strut and coil suspension using KYB strut mounts, strut gaiters, new KYB struts and the ‘correct’ KYB steel springs, Lexus spring seats, bolts and spacers etc. and change all the air suspension later this coming summer.

So, I know about disconnecting the air suspension compressor fuse to avoid warnings on the dashboard display, but can I entirely remove the compressor after removing the compressor fuse?

Used LS430 air suspension struts and air suspension compressors are worth good money, and removing all the air struts and air suspension compressor and selling them on eBay etc would pay for most of my standard suspension conversion!

So, if I remove the air suspension compressor fuse, can I then go onto remove the compressor as well without triggering warnings on the dashboard display?

Advice welcome please!


Old 02-23-18, 02:45 PM
  #17  
toddmorr
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I'd suggest that used struts with 80k miles on them have very little market value but you can always try. I guess you can start to accumulate the parts for a conversion if you're set on it, but it seems early to me. Lots of folks go to 100k with no issues on their struts.
Old 02-23-18, 04:53 PM
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garcea
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You’d be surprised! In the UK used LS430 air struts go for about £175.00 - about $244.00 US due to limited supplies this side of the pond. So probably better to sell the working air suspension struts now before they fail?

There’s a UK specialist LS430 breaker who sells at these prices worldwide on eBay who stresses that these struts come off low mileage cars which he buys for breaking. Low mileage cars he classifies at about 80,000 miles.

i can buy complete in the UK Lexus LS430 OE brand new components (KYB) to convert to ‘normal’ suspension for about $775.00 US - plus professional fitting as I’m probably too old now to do this job myself.

So, what makes better sense. Selling the working air suspension struts now or waiting until they fail and then sourcing the non-air suspension replacements?





Old 02-23-18, 05:16 PM
  #19  
garcea
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But, what I need to know is. If I remove the air suspension compressor fuse and then remove the air suspension struts - can I then disconnect and then remove the air suspension compressor completely (for sale) without having a ‘Christmas Tree’ light display on the driver’s dashboard?
Old 02-24-18, 08:11 AM
  #20  
toddmorr
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Originally Posted by garcea
You’d be surprised! In the UK used LS430 air struts go for about £175.00 - about $244.00 US due to limited supplies this side of the pond. So probably better to sell the working air suspension struts now before they fail?

There’s a UK specialist LS430 breaker who sells at these prices worldwide on eBay who stresses that these struts come off low mileage cars which he buys for breaking. Low mileage cars he classifies at about 80,000 miles.

i can buy complete in the UK Lexus LS430 OE brand new components (KYB) to convert to ‘normal’ suspension for about $775.00 US - plus professional fitting as I’m probably too old now to do this job myself.

So, what makes better sense. Selling the working air suspension struts now or waiting until they fail and then sourcing the non-air suspension replacements?
well if the market for used struts is that strong over there, AND the air suspension is of limited appeal to you, then yes I'd sell them soonest and start your migration. That would be logical.
Old 02-24-18, 11:01 AM
  #21  
GrahamG
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I am sure I have read on here some one following this same procedure and selling the compressor. Presumably with the fuse removed it no longer exists as far as the ECU or any circuitry is concerned.
Old 02-24-18, 11:58 AM
  #22  
rkw77080
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A number of people on the forum also experienced problems with the "Height High" warning light after the air suspension system was removed. Check out the link below for more detail...
https://www.clublexus.com/forums/ls-...onversion.html
Old 02-24-18, 03:48 PM
  #23  
garcea
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Interesting- thank you. The air suspension compressor has other electrical connections as far as I’m aware without removing the protective liner to have a look - other than the compressor motor one which would be disabled by removing the fuse. I guess I’ll just have to find out what happens once I remove the main compressor fuse and then electrically completely disconnect the compressor.

If if I have any further trouble I’ll just leave the compressor on the car with the main 40 amp fuse removed. I see that American air suspensions offer a conversion kit and state on their website that the installation instructions show a quick and easy fix to permanently disable any warning lights. I’ve emailed them to get a copy of their instructions to see how they do it - if they’ll tell me!
Old 02-24-18, 04:43 PM
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rkw77080
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Here are some sketches for the US model LS430. I'm not sure how they differ from the UK version...

You will have to remove 2 fuses and a relay as pictured below (see circled in red).

Here's a sketch of the compressor...


Here are sketches of the front and rear control valves...



If you learn to disable the "Height High" warning light, please come back and post the instructions on the forum for others to know. Good luck!
Old 02-25-18, 12:45 AM
  #25  
GrahamG
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Thanks very much rkw77080 for those diagrams. I now realise there are in fact two fuses and a relay for the air suspension and exactly where they are.
Old 02-25-18, 02:12 AM
  #26  
iriz
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Originally Posted by rkw77080
Here are some sketches for the US model LS430. I'm not sure how they differ from the UK version...
So many components...
Old 02-25-18, 09:03 AM
  #27  
garcea
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Thanks rkw 77080. This is very helpful. Do you know if removing any of these 2 fuses or the air suspension relay will affect the operation of the self-leveling xenon headlights? Having the self-leveling function working with xenon lights is needed here for our annual vehicle safety inspection - known in the UK as the ‘MOT’ test.

If the ‘Height High’ warning is then illuminated I assume that it could easily be defeated by removing its relevant bulb at the back of the instrument cluster?
Old 02-25-18, 01:16 PM
  #28  
rkw77080
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Originally Posted by garcea
Thanks rkw 77080. This is very helpful. Do you know if removing any of these 2 fuses or the air suspension relay will affect the operation of the self-leveling xenon headlights? Having the self-leveling function working with xenon lights is needed here for our annual vehicle safety inspection - known in the UK as the ‘MOT’ test.

If the ‘Height High’ warning is then illuminated I assume that it could easily be defeated by removing its relevant bulb at the back of the instrument cluster?
Removing the 2 air suspension fuses will not affect the operation of the self-leveling xenon headlights.

Unfortunately, the "Height Hi" warning light cannot be easily defeated since the same display area is used for many other warning messages.

Once you remove the air shocks and unplug the actuators, the ECU will "think" the car is riding high. I believe you can fool the ECU in thinking the ride is normal by installing a resistor onto the now-abandoned actuator connectors. I don't have a UL so cannot tell you which resistor to use. Hopefully, someone on the forum will chime in soon.

Old 02-25-18, 01:30 PM
  #29  
garcea
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Thanks rkw77080. This is getting more complicated by the minute!

By ‘actuators’ do you mean the ride height sensors - I’ve read on other posts that both the front and rear ride height sensors have to stay to prevent error messages appearing on the instrument panel?

They no longer control the air suspension as it’s obviously now gone, but give a feedback to the air suspension ECU that everything is still ok?

i know that the sensors on the front are also needed for the auto-leveling headlight system so they definitely have to stay.
Old 02-25-18, 02:34 PM
  #30  
rkw77080
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Originally Posted by garcea
Thanks rkw77080. This is getting more complicated by the minute!

By ‘actuators’ do you mean the ride height sensors - I’ve read on other posts that both the front and rear ride height sensors have to stay to prevent error messages appearing on the instrument panel?

They no longer control the air suspension as it’s obviously now gone, but give a feedback to the air suspension ECU that everything is still ok?

i know that the sensors on the front are also needed for the auto-leveling headlight system so they definitely have to stay.
No, the "sensor" and "actuator" are both part of the control scheme, but serve different functions. The "sensor" measures the current status and report to the ECU. The ECU makes decision based on the input from the sensor, and in turn sends out an output to the "actuator" to do something. Shown below (circled in red) is the actuator for the air shock.



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