Try wedging in a 4 x 4, 4 x 6 block of wood, so when the jack bleeds down it will bite into the wood.
I have a parts car out side sitting on a FJ with wood wedged in to hold it, and my 85
in the shop sitting on a FJ because of a leaky tire.
Holds them good. 85 has been like that for 2 years.
for the bolts holding the 1/2`s together. Clean the threads off good and apply Lock-Tite before tightening them down. Don`t know the torque setting.
On mine, just made them gootentite.

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