Vincenza V

I have a 99' GS4 and the "Shake" after several hundreds if not thousands of dollars worth in parts/labor. It's a second owner car. I got it with 62K miles (now 100K even) and it had "IT-the shake" then on factory 16" wheels with new yokohamas. I now have 20's and Falken 452's. I've done the following repairs and the terrible shake is still there. I won't give up (I'm so close now-)

-new rims/tires, 20's with spacers, tapered lug nuts, and hub centric rings (fail)
-multiple alignments at multiple locations, road force too (fail)
-new front ball joints (fail)
-new Daizen upper, lower, castor arm bushing set (fail)
-new Daizen steering rack bushing kit (fail)
-new Daizen front/rear sway bar bushing kit (fail)
-new inner and outer tie rod ends (help the squirrely steering immensely, tracks perfectly, but still shake-fail)
-new Brembo rotors (about two years ago) and new Lexus installed pads same time frame) (fail)
-new OEM Lexus struts at dealership (fail)

There car drives GREAT around town only, where I go no more than 45. Once I'm on the highway, "the shake" is there as violent as ever. I did detect a pattern though. I though it was random, but it is not. It comes and goes every 4-6 seconds at 55-65-ish miles an hour. Like clockwork. It starts in the floor/chassis, and then radiates through the wheel.

The ONLY thing I didn't replace on the front end are the wheel bearings (they pass the standard test of NO PLAY at all when you grab them at the 12-6 and 9-3 positions. Absolutely none (same with the rear too), so I don't know if they can go bad and NOT have play in them) and the steering gear itself (when I was replacing the inner tie rod end, I inspected the PSG for any fluid leaks, non. It works fine and doesn't leak, so I have to assume it is good).

My suspicions are:

-maybe a stuck front brake caliper? (I do feel a vibration in the wheel when braking in the front now (did two years ago when I went to the new brembo set-up) and the disc is difficult to turn even when the wheel is off. Should it be able to spin more than one whole rotation? It doesn't even do half now.
-maybe a bad front brake line (collapsed?)
-maybe warped front disc's?
-maybe bad front bearings (can they go bad and NOT have play, hmm....?)
-could it be something in the rear?
-I doubt it is a motor mount, car idles smooth as silk in park and in gear.

I will get to the bottom of it (hopefully soon!) and will keep you all posted.

I check my email more often if you have any questions (coshana@hotmail.com)

GS4_Fiend

iTrader: (22)

Did you changed the LCA or LCA #2?

LeoGTE

If all your tires and rims are inw good cindition and you have made all those repairs it would be cosidered steering flutter there is a fix for it that requires the steering rack to be adjusted but only certain people know how to do such fix.

bluwagun

OMG I have the same problem, is this common in the GS's? Vincenza V, I hope you get to the bottom us this. GL

sakataj

iTrader: (182)

says who? there are SEVERAL threads on a DIY for the steering pretensioner adjustment

yes its a common problem but most of the time its fixed with a few things of the above list, mainly the castor bushings and a few others,OP is the only member i know of who has done all this and still has issues

kit cat

iTrader: (6)

Did you change the upper, lower, or both?

vwynn

iTrader: (4)

tighten the steering rack??

Grantville

Steering rack adjustment, a little goes a long ways. But this may not solve the problem.


I have done what you did to your car early this month, go check my $$$ VIBRATION thread about 4 pages deep.

I discuss balance the wheels and got rid of MOST, but not all. I discuss how the wheels may appear to be balance but still cause this shake.

I have a very good shop who went after this issue. They balanced using the latest and greatest, we had bad shakes. Shop owner drove car was like crap!
Then he put the wheels on his Hunter 9700 and they showed to be in balance. At this point he ripped off all the weights after making some marks to show where they were and started from scratch. We ended up with weights in similar place and amounts but not exactly the same. Reinstall wheels and wow o wow, huge difference.

Conclusion these cars are very sensitive to wheel balance and there is probably nothing we can to do but live and deal with it.

bluwagun

Ok I read the following post and understand. I did take my car to the shop and had my bushings and joints inspected. Nothing showed any weakness or being worn out. The original owner to my car had replaced the LBJ, but I read about the funny noise they make, but how about the steering wheel shake while braking that happens intermittently? I all ready replace the pads and recut the disc @ all four corners. By the way I am sorry to thread jack, I will try to help Vincenza V w/our problems and keep this thread updated as I continue to fix my problems, Thanks everyone.

AshburnM3

how about checking your "propeller shaft and its related components" , rear drive shafts

Vincenza V

AshburnM3-"how about checking your "propeller shaft and its related components" , rear drive shafts"

Sounds great, but is there any way to measure what is tolerable "play" or not? Thats the problem. I have the online lexus manual and didn't see a way to check those parts.

Vwynn-tighten the steering rack??

I feel this only PUSHES the problem down to JUST the chassis. It does fix the problem in my opinion.

Cocobun-Did you change the upper, lower, or both?

I did upper, lower and castor arm. On BOTH sides too.

I've been out of work all week sick and haven't had a chance to get the car to my new tire/alignment shop to get their thoughts. I already typed up a list to give to the mechanic to help them in the process of elimination. I feel this will help them bypass the simple "you need a wheel balance" type first responce.

Lately, I have been feeling what seems like a loss of brake power on the right front wheel under CERTAIN conditions. I don't know if it is related to the shake or not. Let me explain:

When backing out of my driveways most every morning, I turn the steering wheel hard right. As I am backing onto the main street with the wheel ALMOST in not all the way cranked over-I press on the brake to stop. I feel what seems is the brake (seems like the front passenger side-but who knows) failing. The pedal kind of "pushes back" against my foot and you lose momentary braking effort. It has done it while going forward with the steering wheel cranked to the SAME direction ONLY. I've been to the lose local dealer and they could find anything (big shock).

Could it bee a collapsed front passenger line? Or a bad front passenger caliper? Could that braking problem affect the shake? Or is this some other unrelated issue?

As soon as I get a chance this week to get the car to the shop with some new eyes on it, I'll keep you all posted. Lexus really screwed up on this car. I don't know why, but I still love it and want to get these problems fixed.

Gunnut

Frozen caliper slide pin?

Vincenza V

Gunnut-I will have the shop check it tomorrow.

Anyone-Is there a way to tell if the caliper slide pin is frozen, or on the way out? Does it just freeze completely or does it "hang-up" before it fail, and more importantly, is there a way to check it while the car is stationary?

Another though I had, do these cars have a rubber rear tranny mount? Could that be split and or deterriorated? I could imagine if we had a rubber mounted one "floating" above the metal part of the mount and causing vibrations. Just a though. But, can't confirm in the manual either. It doesn't show a clear picture.

Gunnut

I was doing a brake job with new rotors and pads. The left side would not turn freely once everything was installed (just like you mentioned). this was before I knew what to look for.
On mine, the pedal was soft until you pumped them a bit and when the brakes were cold (my frozen pin was on the left side) the brakes would grab and pull to the right.

GS300ToM

iTrader: (32)

take the caliper off and press the brakes to see if the piston pushes out.. and then push it back in.. the bolts shud slide back with while the piston is being moved! ( use a c clamp or a caliper brake tool )