LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Rear UCA Replacement - Re-assembly Question

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Old 10-29-16, 04:32 AM
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M4rk
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Default Rear UCA Replacement - Re-assembly Question

Hey everyone,

I am currently in the process of replacing the rear upper control arms on my '97. The job entails disconnecting the UCAs at the subframe, the lower three links at the knuckle/carrier, and pulling the assembly off in order to access the UCA balljoint nut. While the removal process is fairly straightforward, I am unsure about what I think is a crucial part of the re-assembly.

Prior to final torque being applied to all the arms, common sense and past experience with another vehicle tells me the suspension needs to be loaded up with the weight of the car, or at the very least, raised to normal ride height. However, the Toyota service manual I posses makes no mention of such procedure - re-assembly is simply stated as "reverse the installation process." On the other hand, another manual sourced online for an early model LS states to install the wheel, settle the suspension by bouncing it and only then to apply final torque. Quite contradictory..

FWIW, I had the UCA disconnected from the subframe once already, and prior to re-assembly, I raised it to ride car's normal height. Ever since then, I felt like that side was a little unsettled over bumps or perhaps more bouncy. Could be in my head..

Any feedback is greatly appreciated!

Cheers!
Old 10-30-16, 12:06 PM
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dicer
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I am not sure about the rear uca but on the fronts for a gen1 with the metal spherical bushings it really doesn't matter what position its in for final tightening, though I did push it up into its approximate position before the final torque. The one bushing that did matter though is the one at the lower control arm for the shock strut, it needs be loaded to be final torqued. Just put it up on ramps to do it. The thing that tells if it needs to be loaded to final tighten is if it is a full rubber type bushing, something like the front sway bar link ends are not.
Old 10-31-16, 01:10 AM
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PureDrifter
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not needed for UCA.
Old 10-31-16, 04:33 AM
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M4rk
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Thanks, guys. I pre-loaded it anyways because all of the lower links had to be disconnected. No harm in doing so.

Rear wheel play is now gone. Now to muster the strength to swap the pass side UCA as well.
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