Binguyen

I bought a Lexus rx330 (04) about a month ago
And we had the brakes changed about 3 weeks ago, now everytimes I drive faster than 60mph, and press on the brake the steering wheel violently shakes, please tell me what's the problem is

corradoMR2

Mods, move to 2RX forum.

@Binguyen. Sounds like possibly warped rotors which usually can be fixed by getting them machined (or replaced if really worn). Check in the RX forum here for further assistance. Good luck.

Binguyen

Thank you so much, after a little bit of researching, warped rotors seem the be the problem

corradoMR2

You're welcome. And sign up in the New Member thread of the 2RX forum, with pics of your new ride!

SneakyTink

i had the same problem on my sc300. i had to replace my rotors.

mmarshall

I agree it was probably warped rotors, but that doesn't mean that they were necessarily warped or had runout when the brake job itself was done. If some bozo put the wheels back on while using a classic air-wrench/impact wrench with too much air-pressure, or hand-torqued the lug-nuts down too much, that can warp a perfectly good set of rotors in a hurry (it happens far too many times). The best way to do it is to use a torque wrench and hand-torque the nuts to the proper figure....which, for many vehicles, is around 75-80 ft-lbs., but the exact figure will be given in the Repair Manual for that vehicle. Also, if they are going to re-shave the rotors to get them smooth again, there has to be a minimum amount of metal thickness left anthem, as shaving them removes a small layer of metal each time it is done. Again, the exact amount of minimum allowable metal thickness on the rotors allowed for safe operation is spelled out in the vehicle's Repair Manual. If you don't have enough metal left on the rotors, then they have to be replaced......which, in your case, may be justified at dealer expense.

There are a number of other things that can cause steering-wheel-shimmy that have nothing to do with rotors (out-of-round or unbalanced wheels/tires/hubs, wheel balance machine not calibrated properly, unevenly-matched wheel lugs that don't all weigh the same, internal tire defects, etc....... But, in your case, if the wheel shakes only when when the brakes are applied, it is usually the rotors.

Sulu

Out of balance wheels may only cause a shimmy/shake at certain speeds -- slow down and you won't notice it. Wheels may be thrown out of balance (temporarily) by ice and snow getting caught (and freezing) in the wheel (rim); this is more likely to happen with alloy wheels that have distinct spokes that leave large areas in which snow can get caught.

If you have ever parked in a snowbank and then driven away without clearing the snow from your wheels, that is when it is most likely to happen. Earlier this year, on business, I flew into a small airport in the US midwest and picked up a rental car. This was just after a heavy snowfall and while the parking lot had been cleared, there was, understandably, many snowbanks; the Chevy Cruze with alloys rims I picked up had been parked near one. I drove off and only when I was on the interstate did I notice the speed-sensitive shimmy. I pulled off the interstate into a small town, stopping in a parking lot. I cleared the accumulated snow and ice as best I could from the wheels and once driving again, noticed much, much less shimmy.

mmarshall

True......but heat from the nearby engine compartment and from using the brakes often limits the amount of snow and ice that freezes and builds up on the wheels.

In general, with steering-wheel shimmy, depending on the exact cause, one starts to notice it around 40-45 MPH, and it is often at its worst in the 55-70 MPH range that many people drive at on the Interstates.

BTW.....just for the record, I'd like to note that shimmy used to be a VERY common problem, even in brand-new cars right out of the factory, because of a number of flaws in the assembly process.....bent or out-of-round wheels/rims, out-of-round tires, tires not balanced properly, internal tire defects, defects in the wheel hubs, bad brake rotors, wheel balance machines not calibrated properly, etc..... It is much less common now to have cars come off the assembly like that....but it still occasionally happens.

NickTee

Another thing that can cause this is tie rods that have a ball-joint that is failing.

mmarshall

Usually, though, unless the suspension is damaged, that only occurs on very high-mileage vehicles, although the OP did day he had an '04.......which makes it 11 years old.

Sulu

Shimmy can be caused by out-of-balance front or rear wheels. And if it is a rear wheel that has the ice buildup, there will no heat from the nearby engine compartment to melt it.

The rear wheels had the ice buildup in my rental car and it was also backed into its spot. What likely happened on that car is that it sat in a snowbank / windrow (it was the last car in the row, next to the sidewalk) from a relatively warm snowstorm that was quickly followed by a deep freeze.

I did notice the snowbank but because the car was not stuck, I drove away, only to notice the shimmy on the higher speeds of the Interstate. Thinking that ice buildup may be the cause, I stopped to try to chip away the snow and ice, wanting to see if that would reduce the shimmy before calling Avis to say that there was a problem with the car. Seeing that it was ice buildup, the temperatures were particularly cold the week I was there and the short distances I would be driving each day, neither engine heat nor brake heat would likely have melted the buildup (it certainly did not prevent or reduce the buildup).