My steering wheel will vibrate when I hit about 55MPH and it'll also vibrate when I'm braking (various speeds) and it happens on and off - sometimes the steering wheel will vibrate, sometimes it won't.. i don't understand it?!

 

for the braking vibrations, sounds like warped rotors in the front. they need to be turned.

however, while driving vibration, you mite need a tire balance.

 

warped? i just got them though, they're brembo's.. and what's it mean to have them turned?

as for the balancing of the tires, how do i know if they need to be balanced? should i just take them to where they were balanced originally?

 

oh, and the vibrations when i brake, they only happen for a few seconds, it's not the WHOLE time i'm braking..

 

Did you replace the pads at the same time as the rotors?

 

yes, i replaced all 4 pads when the rotors were put on. the back rotors and pads were put on before the front rotors and pads were, they are about 2-3 days off from each other.. don't know if that makes sense?

 

how many miles are on your car?

 

i have just reached 98000 miles

 

When you had your brakes done did the shop bleed your system ? Make sure that they did because you dont want air in your lines which could cause your calipers to seize up, the repair and expense behind that is costly.

 

why would they need to bleed the brakes? the brake lines were never removed from the calipers, but we did compress the pistons, which wouldn't allow any air in, right?

 

make sure your tire pressure is good too

 

This is a common problem for the GS especially if you have aftermarket wheels. I fixed my steering vibration by getting my wheels/tires balanced and rotated.

Do a search on CL, this has been discussed many times.

 

98000 miles

bushings bushings ,balljoints and tie rod ends.. remember folks lexus designed these cars mainly for luxury and comfort , they had very little tolerence for sport tuning susp wise, when going to 19 and 20 in and going with lower offsets with wide tires up front and you are lowered you are changing the dynamics /geometry of the originsl design .. you are wearing bushings and joints at a much faster rate so all imperfections will be amplified


the daizen bushing upgrade will take care of shimmy, vibrations and wandering it will also take care of brake pulsing sensations you described provided your rotors are not warped or you dont have brake pad sploaches on the rotor surface

 

bleeding brakes is usually only required if the master cylinder reservoir fluid gets very low or you break a line loose and introduce air into the system.