mi430

Hi, I'm not sure if this subject has been brought up before, but I haven't seen a thread on it yet. I drive an '05 sc430 and the steering wheel shakes at above 50mph when I lightly step on the brakes. I have recently had my brakes done and an alignment done as well as both rear shocks replaced. Before I go out and spend more money, does anyone know if something else could be going on?
Much appreciate the responses!!

Off the topic: I love SC's!!!! My bro has been driving a '92 SC400 and that beauty is still beautiful and going strong!

braheem

iTrader: (4)

If you have aftermarket rims get hubcentric rings and a force balance.

mi430

No aftermarket rims..they are stock. Could aftermarket rims give me a smoother ride?

braheem

iTrader: (4)

I would try a force balance first.

PS, I know faulty rotors is usually the cause, I'm assuming they were turned. A badly balanced wheel will also start shaking when the weight of the car is shifted to the front wheels, ie braking.

mdpuff

The shake is in your brakes, you have warped rotors. If you just had you brakes done find out if they machined your rotors. Most times when brakes are done they automatically machine the rotors but if they didn't and just threw on new pads they do need to be machined. Another alternative is to put new rotors on, there are lots of cross drilled to choose from, they have holes drilled in them for better cooling and resist warping much better. Hope this helps!

cyberlexus

iTrader: (2)

I agree with mdpuff. Most likely, the pads were replaced, but the rotors are not. The rotors need to be resurfaced or replaced when new pads are installed.

mi430

Thanks for all the suggestions! Those were all very helpful. I think I will bring it to another shop to see if they "machined my rotors". I hope I get some answers there. Wonder why a shop would work on it if they had not known to do that. Hopefully those symptoms did not further damage my car. ^_^

SteadyEddy

iTrader: (1)

I wouldn't take it to another shop yet. Take it back to the one that has already gotten paid for the work. Ask them what they did. Ask them if they had checked the run out on the rotors. Then tell them what is happening. If they are any good they will make it right. If not then go to another shop. Then you know never to go back and tell all your friends. Maybe turn the into the Better Business Bureau.

mandyfig

Make sure who did the brake job torqued the caliper bolts to specs. If the rotors were turned and turned correctly, that is the only root cause for the shaking. Who did your brakes?

OBP

I had exactly the same symptoms when I replaced my front brake pads and rotors on another car ( not the SC but our Acura RL) recently. The front of the car would shake when I hit the brakes. Learned that with new pads and new rotors, you need to bed in the pads. The process involves progressive application of the brakes in quick succession. It should be detailed on many brake manufacturers websites.

I did the bed in process a number of times on a weekend and my front end vibrations and steering wheel shakes are gone. Took a while and lots of worries about what was wrong with the car but now, my slotted rotors and after market pads on the RL bite good and hard, better than OEM.

Here is what some brake shops and specialist brake websites told me: steering wheel shakes when braking implies issues with the front brakes/rotors. Pedal vibration when braking means issues with the rear brakes/rotors.

Thankfully, my SC has not had any such issues but then I only changed the pads, not the rotors on my SC.

Last thought: some brake shops say over torquing the lug nuts can cause rotors to warp. Did you ask the brake shop that did your brakes what they torqued the lug nuts to ? I think for our cars, the lug nuts ought to be about 80 or 85 lbs but Mandy knows this stuff by heart so chime in Mandy.

Good luck mi430, let us know what happens.

hypervish

Sounds like the rotors are warped.
I agree with the above poster, over-torquing the lug nuts can cause severe warpage on rotors.

Rickard

I hate to bust your myths, but generally, rotors don't "warp". And they certainly aren't going to warp from over-tightening the lug nuts. Do a Google search and you'll find some articles written by a Stoptech engineer who discusses these points.

The most common problem with rotors is a buildup of material on the rotors which causes a variation in the grip with the pads.

hypervish

Over-Tightening the lug nuts will most definitely warp the rotors. If you don't believe, go try it yourself... LOL

Yes, the most common is pad material on the rotor. But, that only happens if you've overheated your pads at one point, and then stopped at a red light. That will eventually work it's way off.

Rickard

Here's the article: http://www.stoptech.com/technical-su...nd-other-myths

scdroptop

iTrader: (1)

I think you are both right, in certain circumstances. Typically you will see the "warping" affect after a pad job when they so-called turned or machined most likely because they did tighten too much. It usually takes a second visit to adjust or bed like aforementioned to work it out. If you notice it right away after leaving-regardless...take it back! However most common initial rotor issue is that there is a major build up that needs to either be machined or turned...see below.

On a similar note, took my 2009 FX35 with 20k miles on it back to dealer for the 4th time for brake squeaking and wobbling and they machined and turned rotors as well as measured pads and adjusted but plenty of life left on them. I have had this FX since new in 1/09 and on original pads, rotors but they have been adjusted about 4-5 times, machined, turned, etc. This is my 4th G/FX model since 2003 with the 3.5L V6 and similar setups and they all have had squeaky and wobbling brakes from time to time. The service tech always remind me that "high performance brakes...blah blah blah". How come you don't hear the Porsche guys complaining about brakes all the time? HUH? Riddle me that! LOL Oh well. Like my wife says, I wouldn't be satisfied if I didn't have anything to complain about!