vagluv

I have some fairly serious steering wheel wobble while braking, but only between 60-50 mph. The rotors are fairly new, but that's my first thought. Is there anywhere else I should be looking?

Thanks!

Navaros911

Front suspension bushings... or, it may be the rotors or how they are mounted.

I've had brand new rotors that were out of tolerance... and I've heard of corrosion on the hub behind the rotors. Both giving issues like this.

rdean

I had the same problem.
It was deposits from the brake pads from over winter storage.
You can have your rotors scimmed or try to remove the deposit with a garnet based abrasive. Or wait for normal wear to resolve the situation.
Nonetheless a very un-nerving driving situation.
Good luck.

R6XTERRA

check your wheel bearings. Only other thing i could think of is worn rotors...but you have that covered already.

vagluv

Thanks, I'll check there.


I doubt that's my issue, as the car never sits too long. May end up having them ground though to see if they need to be straightened out.

This was actually my second thought. I just had to do both rear bearings, so maybe it makes sense that the front ones are shot too.

J richard

Do you autoX or DE the car? Or drive it with heavy brake use? If so pad deposits could very well be your problem...

KaiB

I've got a set of Hawk Blues here.

What size brakes are you running?

We really should pass these around to clean rotors.

BLACK-BETTY

I'm sure you do!

But these chewed up a set of discs like nobodies business on my car. Huge amounts of break dust too!

They're fine for a race car but not for a streetable track car. But yeah these will definitely shave a disc.

KaiB

That's what I mean!!

Worthless actually, for all but one thing. One lap around the block and the rotors are deposit free.

I'm thinking we could use my set to pass around to RL'ers for just this.

(I use Pagid Yellows)

boxsey911

Loose wheel nuts?

vagluv

Never anything but a little heavy braking while road driving.

Haha, let me inspect the rotors first. All are standard sizes.


Would surprise me, but I guess it's possible. The strangest part is that it really only happens in the 50-60 window.

vagluv

Does anyone have a link to a front wheel bearing DIY?

J richard

Pad transfer is the result of brake pad material effectively being "melted" in the process of heavy braking and transferring onto the disk. It happens with all pads and is part of the process of bedding in new brakes (moreso than "grinding" the pad to the disk irregularities) It is actually less prevalent with racing pads due to the fact that they are designed to take much higher temperatures. If you are using stock street pads and do some heavy braking you can cause it. Mixing different compounds on the same/ undressed disk causes this as well. The shudder is not a warped disk but the pad gripping and slipping that will cause the wheel to wobble just the same. The solution as Kai mentioned is using an aggressive compound to clean the disks. Grinding the disks will eliminate the problem but it will simply reoccur the same way with the same pad and you loose disk depth and heat sink in the process. Sanding the disk can work but the irregularity is hard to see/eliminate.

By all means check the bearings and lug nuts, tie rod ends and lowers, those are safety issues. But if the runout on the disks is ok I would look to changing out your pad selection and skimming the disks to remove all deposits. If it happens again you need a different pad to work with the type of driving you do.

vagluv

Thanks for the info! I am running Hawk Performance Ceramic pads, and was careful to bed them when they were new. Would what you're describing not be present at all speeds?

92C2Targa#119

Maybe seized caliper piston. For me it was hard braking at 70-80 miles/hour only, and found one piston was seized, replaced caliper and all was good.
Cheers