Tech

Hello everyone, 04 w/ 82k miles, suspension started to sag & compressor was activating frequently.

DIAGNOSIS

Thread............... Air Suspension Problems on GX470
After reading this entire thread I concluded the air springs were leaking. Page 10, post #143 by Invalid143, led me to this conclusion.
QUOTE Hey guys, I was looking through the thread and wanted to toss my .02 in here. I work for Lexus and have noticed 1 major item missing from the things everyone has replaced. Height sensors, yes, those do seize and/or break often. Shocks, yes, they can leak, but its not a major deal. I believe alot of techs over-sell them. What i'm not seeing in this thread is that nobody has replaced the airbags. Those are possibly the cheapest part of the AHC system! We've done a few sets here at the shop. I wouldn't say its common, but with some of the strange happenings, strange ride heights after sitting, leaning, etc.. They can develop pinhole leaks. And when the pump is on constantly trying to maintain that ride height, it will shut off after a predetermined amount of time to save the pump from burning out. And that could cause the exhaust solenoid codes and other codes because the ecu is tricked into thinking those could be the issue. It can't monitor air pressure inside the airbag (although that would be nice)

Just trying to help share some knowledge. END QUOTE

AIR SPRING REPLACEMENT

This youtube video was a great help w/ most of the details for replacement.


This special tool...the smallest one...is indispensable for disconnecting the air supply line on top of the air spring while it is in place.

https://www.ebay.com/itm/7pc-Quick-D...53.m2749.l2649

I bent the metal in the wheelwell up to allow my hand to get access to the flat clip holding the air spring in place. This clip is easily removed & reinstalled.

REAR SHOCK REPLACEMENT

This was very simple....disconnect the top & bottom bolts & the electrical connector, remove shock, reinstall.
I used some compressed air on the electrical connection to get some of the dirt out of the connector before separating.

FRONT SHOCK REPLACEMENT

This was a difficult job. The suspension does not need to be dismantled....so you do not have to get a new alignment after completion.

#! - The electric operator on top of the shocks is attached w/ -0 2 small allen head screws. The rear one is difficult to remove. I used a grinder to shorted the allen wrench to ease removal.

#2 - Disconnect/move out of the way, the sway bar.

#3 - 3 top bolts & 1 bottom bolt are easily removed. The strut will be wedged in. I used a pry bar on the coil spring to facilitate removal. Since I did not remove the sway bar I had to rotate the shock/strut in a screw like motion to remove it from the suspension.

#4 - I put the bottom shock mount in a vise & attached my Harbor Freight spring compressor to facilitate shock removal & reinstallation.
Make sure to rotate the shock top in accordance w/ the attached PDF for installation. This step is critical to an easy reinstall.

https://www.harborfreight.com/macphe...set-63262.html

#5 - Reverse steps 3, 2, 1.

COST & VENDORS

Air springs Right Rear Ebay APS $114.00
Left Rear Cool Springs Toyota $238.00

Rear Shocks Ebay Asian Auto $780.00

Front Shocks Bell Lexus $354.00

Disconnect Tool $7

Spring Compressor $35 I did not have this cost ...I already had this tool

Grand Total $1,493

CONCLUSION

The ride is now absolutely wonderful. KDDS works fantastic. This is my wife's car, purchased used 6 years ago w/ 27,000 miles on it. She is VERY particular & gives it a 10++

I HIGHLY recommend replacing the airs springs, F & R shocks w/ OEM Lexus parts as a package.

LoganDon

Great, informative post.