Wanted to document my experience with upgrading the rear springs on my 100. For reference the vehicle is a 2006 LX470 with 157k.
A little background - I bought the LX from the previous owner who had replaced all four AHC shocks with new OEM. When I bought it the ride seemed excessively harsh, but I wanted to keep AHC because it is really a great system. I replaced the globes with Pleiades about a year and half ago. This alone restored much of the ride quality. After performing cross leveling / adjusting torsion bars to get the front pressures in spec, the ride improved further. Rear pressures were on the high side but I left it alone at the time.
I recently added a Front Runner slimline roof rack and a pair of ARB drawers. Love the rack and drawers however on a recent trip the suspension struggled to stay at N, frequently dropping to Lo on its own. I suspected the rear springs could no longer handle the weight fully loaded with the rack, camping gear, and passengers. Confirmed this via techstream rear pressure was reading 8.0mpa (far above spec) with drawers loaded, driver only, and no other gear such as cooler, tent, etc.
Installation of the King rear springs was straightforward with two jacks and two jackstands. Disconnected the rear sway bar, and replaced the springs one side at a time by temporarily disconnecting the lower shock bolt to get enough clearance to swap the spring. I lowered the axle on one side only enough to get the spring out, while being careful not to over extend the AHC height sensor or any brake lines. I also swapped over the OEM rubber isolators (is that what they are called?) both top and bottom onto the King springs - edit: insulator, rear coil spring upper/lower seems to be the part name. None of the install guides I found mentioned anything about these. I decided I wanted my ride to be quiet and vibration free and figured avoiding metal on metal contact would help achieve that. If anyone has experience with and without the isolators (attached pic), feel free to chime in. After installation the ride is indeed quiet so I am happy with my decision to re-use them though at this mileage it might make sense to replace them.
Techstream shows rear pressure in spec and reduced to 5.9mpa with drawers loaded and driver only. Front pressure also dropped about .2-.3mpa to 6.2mpa - on the lower side but the ride quality feels good around town. Overall ride feels less sloppy, more controlled than before yet still incredibly comfortable. Looking forward to seeing how it performs on the next trip.
A little background - I bought the LX from the previous owner who had replaced all four AHC shocks with new OEM. When I bought it the ride seemed excessively harsh, but I wanted to keep AHC because it is really a great system. I replaced the globes with Pleiades about a year and half ago. This alone restored much of the ride quality. After performing cross leveling / adjusting torsion bars to get the front pressures in spec, the ride improved further. Rear pressures were on the high side but I left it alone at the time.
I recently added a Front Runner slimline roof rack and a pair of ARB drawers. Love the rack and drawers however on a recent trip the suspension struggled to stay at N, frequently dropping to Lo on its own. I suspected the rear springs could no longer handle the weight fully loaded with the rack, camping gear, and passengers. Confirmed this via techstream rear pressure was reading 8.0mpa (far above spec) with drawers loaded, driver only, and no other gear such as cooler, tent, etc.
Installation of the King rear springs was straightforward with two jacks and two jackstands. Disconnected the rear sway bar, and replaced the springs one side at a time by temporarily disconnecting the lower shock bolt to get enough clearance to swap the spring. I lowered the axle on one side only enough to get the spring out, while being careful not to over extend the AHC height sensor or any brake lines. I also swapped over the OEM rubber isolators (is that what they are called?) both top and bottom onto the King springs - edit: insulator, rear coil spring upper/lower seems to be the part name. None of the install guides I found mentioned anything about these. I decided I wanted my ride to be quiet and vibration free and figured avoiding metal on metal contact would help achieve that. If anyone has experience with and without the isolators (attached pic), feel free to chime in. After installation the ride is indeed quiet so I am happy with my decision to re-use them though at this mileage it might make sense to replace them.
Techstream shows rear pressure in spec and reduced to 5.9mpa with drawers loaded and driver only. Front pressure also dropped about .2-.3mpa to 6.2mpa - on the lower side but the ride quality feels good around town. Overall ride feels less sloppy, more controlled than before yet still incredibly comfortable. Looking forward to seeing how it performs on the next trip.
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