Wobbles During Braking...Have NEW Rotors and Pads. What Is It?

MLC Stang said:

You didn't say if you got new front brakes, back brakes, or both.

If only one or the other, it might be the other!

If both, you might have a bad wheel bearing on one corner or you might have improperly torqued lug nuts causing a "warp" in an otherwise new rotor.

Click to expand...

Is there a general method of diagnosing a bad wheel bearing? Don't want to steal this thread but I have a similar problem with vibration. I've balanced the tires, replaced the rotors and pads, even replaced the tires and still get this intermiten shake. You can hear it in the tire noise at slow speeds.

any idea ???..

c-zap said:

Is there a general method of diagnosing a bad wheel bearing? Don't want to steal this thread but I have a similar problem with vibration. I've balanced the tires, replaced the rotors and pads, even replaced the tires and still get this intermiten shake. You can hear it in the tire noise at slow speeds.

any idea ???..

Click to expand...

you can take a look at them (visual check).

and, before hand: jack up the front end. use jack stands and be safe and all that. grab a wheel at 3 and 9 o'clock and push pull on the tire (in the direction like steering the car). do the same at 12 and 6. if you have play at both, that suggests wheel bearings. if you have play at just 3 and 9, that suggests tie rod(s) . if at 12 and 6 only, that suggests ball joint.

you can further check (look at the tie rod, etc) while pulling to look for movement and so on if you get slop somewhere. a lot of this is a feel thing, but that is some general info to see if it checks out.

good luck.

Thanks. I'll give it a try this afternoon.

What happenend when your strut went bad on you?

Might wanna check for vacuum leaks. I run a B303 cam and it takes a lot of vacuum away from me so my brakes (when below 1500RPM) pulsate somewhat as the cam turns...as I understand it this can cause your brake booster to pulsate in strength.

Of course it doesn't help that I have big 13" Bullitt brakes in the front, either, but front/rear new everything and I still have a pulsating feeling.

SS

I did some reading a few weeks ago and it mentioned 'indexing' the rotors.

When mounting new rotors- they should be installed on the vehicle and indexed with a dial indicator to minimize runout. New rotor runout is typically between .002" - .005" However, failure to mount the rotors ON THE VEHICLE and measure TOTAL runout can cause a vibration even with brand new rotors. You should check hub runout as well- since a very small amount of hub runout (even as small as .002") can create additional runout of as much as .006" - even with perfectly true rotors.
This is similiar to mounting and balancing tires. Often times a rim and tire combination that would require additional weight to correct balance can be rotated and then require less or no weight to balance.
This means you should test the rotor in a number of configurations and install it in the confirguration which results in the LEAST amount of total runout.
http://www.raceshopper.com/tech.shtml#warped_rotors