Is it OK to position floor jacks where the green arrows are pointing in the picture? Are those "frame rails" solid enough? I've read that many people don't like using the sills, as the sills can bend or warp over time.

 

Never have had a problem with the pinch welds deforming myself, but I also use rubber pads on my jack stands, and the aluminum pinch weld load spreaders in the rare occasion that I need to jack it up on the sides.

Could you use the frame like what you have shown? Not sure .. I just stick to the FSM instructions myself

 

I stick with the FSM jack points as well. The pinch welds are strong enough; as long as you lift in the specified location. I wouldn't try lifting at the pinchweld/body under the doors, etc.

Consider the emergency jack that's in the trunk. The pad is metal and designed to lift across the pinch weld.

 

If yer using a trolley jack, use the points shown in the Owners manual (diff at rear, just in front of the sump at the front).
Once you have her jacked up place axle stands on the hard-points (subframe mounts or on the subframe itself).
If you must lift with anywhere that is not thick steel (eg. sills or "frame" rails) then always use an appropriate pad, especially with the pinch welded sills.

Your picture is of the underside of a Mk1 (89-92) LS400. The LS430 is similar but not the same.

 

The pinch welds may fold over, go for the main rails or subframe.

 

now that it is up there, what are double shims on the brake pads for?
do you re use shims or just leave them off?
1st LS had brakes from brake shop but this one has real LEXUS brakes
what is difference.

 

Double shims are anti-squeal. Many brake shops use aftermarket pads that the shims don't fit on, so they throw the shims away.

 

Do not lift the car from the two areas you pointed to in green. Only lift from the specified points in the manual

Too many mistaken the floor pans for frame rails. I have seen plenty LS 400s and 430s with bent floor pans after being lifted from there. The damage is permanent, tears the undercoating, and can cause rust.

EDIT: Here are some examples of what can happen if you try to lift these unibody cars by the "frame rail", which is actually the floor pan..

https://www.clublexus.com/forums/ls-...l#post11611773

https://www.clublexus.com/forums/ls-...l#post11611799

And an extreme example last year where the floor pan actually split because it was lifted near a seam:
https://www.reddit.com/r/Lexus/comme...or_pan_repair/

 

If I’m removing only one wheel, I just a floor jack with block of oak at the pinch weld jack point. If putting the entire car on stands, I jack the rear under the rear diff or front in the center of the cross member and put jack stands at the pinch welds. I use Lincoln jack stands, which have shallow troughs, not the V shape found on inexpensive stands. So far, 15 years and no issues. Remember this and most cars are monocoque like a turtle shell, not built on a ladder chassis like a truck, so you can just jack anywhere what you think is a cross member. Only Lexus on a ladder frame chassis would be the GX and LX.

 

I too use the cross members to lift, and put stands at the pinch welds. Even if I'm just removing one wheel, I still lift the entire front/back end.

I use pads on the stands so that the stand pad straddles the pinch weld. I have rubber pads in place. This mimics the jack pad that's on the emergency jack in the trunk.