Ok, guys.....

Previous symptoms:
A creaking/popping noise is heard from the front end of the SC400 while braking at slow speeds. Ex: after shifting from forward to reverse and vice versa while pulling in or out of parking spots. Slightly more than light braking while approaching a stop sign.

Attempted repairs: New lower control arms incl. lower ball joints
New upper control arms incl. upper ball joints
New sway bar end links
New sway bar bushings
New steering rack bushings
New Shocks and springs

Nothing worked!!! or worse

The solution:
Retorque the (4)17mm nuts which hold the aluminum crossmember(cradle) onto the unibody chassis.The 4 17mm nuts should be torqued down to 94ft/lbs.

Another to check while you're under there are the (6) 19mm bolts which hold the steel crossmember located rearward of the aluminum crossmember. The 6 19mm bolts should be torqued to 148ft/lbs.

A 17mm deep socket/19mm socket, 6" extension, and a long handled ratchet will do the job just fine.

 

The following posts show the locations of the two 17MM bolts you'll need to retorque. There's a front and rear on both the left and right sides for a total of 4 nuts altogther.

 

Location # 2 ; The rearward most nut.

 

Hoping for the best on this. I also have replaced LCA's and went to a supra/bilstein coil. Still have a little clunk from the front right. Same parameters as you describe as well. Thanks. I'll tighten them this weekend and reports back.

 

Cool, I'll check mine out next time I am under there.

 

Will give it a try as this week.

 

I will check this out tomorrow. I changed control arms and rack bushings and I still hear a slight clunk coming out of my driveway. Its coming from the front passenger side.

 

OK I just torqued them down and NO MORE clunking when driving out of my driveway!!!!!

I can't believe it was that simple. I didnt even jack up the car. I just turned the wheels and laid on the side and tightened them. Took about 5-10 minutes.

Thank you UpInTheLex for this tip.

 

and the proper torque setting is?

 

Ill give it a shot this weekend!

 

Tight..........

We're not assembling a bottom end of an engine here.

Ok fine, I won't be an ***. 60-70 ft/lbs seems reasonable if tight doesn't do it for ya!

 

good info will try this when i change my brakes

 

You win. Good job man. I didnt get it entirely tight because I didnt have my airtools with me, but yup, its loose. So Ill hit it with the impact whenever I get the chance.

One thing is, are they both 17mm? One is 17mm the other is a lot larger...

 

All 4 of them were 17mm on mine. Might need a deep socket though as the ones I had barely reached.

 

So the popping/clunking/creaking noise is gone now?

The 4 Aluminum subframe nuts are all 17mm.
However, the black painted steel Tranny crossmember behind it has larger bolts.

The front 17mm nuts are easy to find.
The rearward ones are a little sneaky... You have to slip around behind the lower control arm to find it.

Definitely use a 17mm deep socket.