Steering wheel shake?

cotizi

Quick question for those who know much more about braking/handling systems than me.

Last night I was screwing around with my G-tech trying to work on my launching, 0-60 times, etc, and I noticed after about 30 min of what I would say is moderate braking, I started getting some shaking in the steering wheel during light /moderate braking at like 70-80mph range. Its not physically shaking noticeably, but I could definitely feel it in the wheel, and this is definitely something I haven't felt yet since I bought the car.

Any ideas what the possible causes of this are? I've never really gotten on the brakes hard at all, aside from the occasional hard stop to show friends they work

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Past - 2009 Silver 6MT Sport 370Z
Current - 2012 VW GTI 6-Speed

molamann

Braking and car moves strangely.

Anything like that? If it is, Modshack has a good explanation on page 2.

davidyan

You may have warped your brakes from constantly braking from high speeds. What may have happened is the brake discs overheated and are now slightly uneven, resulting in some vibration in light braking. Either that or the fluid is overheated. Hopefully, its temporary. I would let the car cool down overnight and try it again in the morning.

cotizi

Same problem this morning on the drive to work. Only on light braking from 60+ mph range do I feel the wheel start to vibrate.

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Past - 2009 Silver 6MT Sport 370Z
Current - 2012 VW GTI 6-Speed

370Zsteve

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SOLD MY Z MARCH 2018 - another Core OG moves on - new ride 2019 Z Corvette Grand Sport - no mods necessary but already have eyes on HFC and intakes LOL IT NEVER ENDS.

WhiskeyHotel

Yep, it sounds like the rotors are slightly warped from the braking session.

imag

One of the brake guys should correct me if I'm off, but my immediate thoughts was pad deposits on the rotors. If you got them heated up, then stopped in one place with the brakes on for a bit, or put the parking brake on for a bit, that would do it.

You can get the rotors resurfaced. Any brake shop and even most mechanics can do it. And don't let someone try to make you think you need a whole new set of rotors.

If you have abrasive pads (HP+), it's possible you can repeat the bed-in procedure to remove the deposits. If you don't know how to do this, I recommend resurfacing.

G37Sam

Yup definitely warped rotors

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cotizi

It was definately some stop-start. 0-70 brake, stop. launch, 0-70, etc.
and then after about 15 min or so I parked for awhile after stopping to talk to this guy in a 2010 STI who loved my car.

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Past - 2009 Silver 6MT Sport 370Z
Current - 2012 VW GTI 6-Speed

Solus

I did the same thing. pad deposits... got the rotors turned works just fine now

imag

That will do it. Never use the parking brake after those kind of runs - just leave it in gear and turn it off. Also, after heating your brakes up, if you need to wait at a traffic light, or need to stop and talk to someone (like the marshal who black flagged you ), make sure you let the car roll slightly or move it every few seconds.

The good thing is that it's a relatively cheap fix...

antennahead

Don't immediately assume it's warped rotors, as others have said, may very well be pad deposits, and most likely it is........ unless you did something wacky like ran through cold standing water with very hot rotors.

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WhiskeyHotel

Either way, the solution is to have the rotors turned.

ResIpsa

The technical term for what you are experiencing is "brake judder." And "brake judder" is caused by an uneven layer of pad deposits on the rotor.

If your rotors were truly warped then you would experience the vibration all the time. They would vibrate when cold and when hot.

I was able to cure a brake judder problem on my Z with 3M Roloc Discs attached to a drill. I used one disc for each surface and gave my rotors a good scrub. Voila! Problem solved.

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AP - Chris_B

+1 on this answer. You could also try a Flex-Hone, which is pretty quick and effective. The trick is to remove the uneven pad transfer layer, not iron. Then re-bed the pads and you should be good to go. When bedding, always remember that proper cool down is critical. You never want to press hot pads against hot rotors at a standstill.

This is why bedding procedures should never dictate a full stop. It's usually 35 down to 15 several times, then 55 down to 25 several more times, etc. Once they are hot, you can feel the green fade starting and you can smell the pads. Drive at least a mile without using the brakes to "freeze" the transfer layer in place.

Chris