I recently changed my front pads (Stoptech Streets) and rotors since when I got the car it had awful brake vibrations. I did the bed in process recommended. However I probably have about 1k miles on these rotors and pads and already I'm noticing vibrations when applying the brakes. What would cause this?

Second question; I'm debating on a RSB or doing the TRE rear dif. Its my understanding that the rear dif upgrade is night and day difference, how ever this is just a daily driver that sees quite a bit of spirited driving but will never see the track or autoX. Would it still be beneficial to go ahead and do the rear dif, or would just a RSB get the job done about as well?

 

bump.

 

for street driving, the RSB would probably be safer than the diff. If you push too hard on the street, and that diff locks, it's no joke. The rear diff change is night and day like you said. The RSB should help reduce a little understeer, but not completely change the car. But if you're getting understeer on public roads, you drive a LOT harder than me.

 

I would do the OEM restack in the rear diff. Still a very noticeable difference vs stock, but not to the point where you need to be worried about the rear-end overtaking the front.

 

^Restacking the diff would probably be a nice happy median. Another thing to consider would be an ACD reflash.

However, lets backup a second. Why are you even considering a RSB of diff upgrade in the first place? What is the car doing that you would rather it didn't? If you are solely street driving then Im not sure I would do any of that. Maybe I'd restack the diff since its essentially free but whats the point of throwing $ at something if you arent even going to take advantage of it?

 

I live 45 minutes from Deal Gap so the car gets to see quite a bit of spirited driving and there is definitely pronounced understeer with the Bil's and springs. I just want to get the rear end a little more free.

But back to the brakes. I've noticed that there are places on my rotors now that it looks like the pad has seated against it and sat for a while, I'm assuming thats what is causing my brake vibrations. I too have noticed that after washing my car and letting it sit, as soon as I go to back out or what ever I can hear a seized pop/creak from the front end of the cars, which is assuming the pads seating down on to the rotors. What would be the cause of this and how to fix it?

 

I wouldnt be too concerned about the issue you seem to be having with the brakes. I'd venture a guess that after the first true stop it the pads would scrub off the deposits on the rotor and the little vibrations should go away. I daily drive my car as well as auto-x it and what I have found is that while dd'ing it sometimes I will get a little pulsation while braking but this isnt during a hard stop. These pulsations do not occur while racing however or while doing a hard stop. You could always try rebedding them and see if that changes anything.

As for the suspension, what springs do you have on there? What is your current alignment and what tires are you using? Is the car pushing on corner entry or while trying to put the power down on corner exit?

 

So I went out to the garage and pulled out the old rotors I took off, you can see the lip that was cut and worn in to the old rotors. Then these are the places that I was talking about on the new rotors. For the first few hundred miles, there was absolutely no vibration, and now there is vibration beginning around 60mph.

 

When braking or just driving at 60mph?

 

Both.

 

how old is your car? how many miles? and what are your driving styles with your car. I'm going off my best guess that you may be developing steering play in your linkage check for rack and pinion leakage or even lift up your front end and wiggle your tires from side to side (hands at the 3 o'clock and 9 o'clock position) if you feel play then start there usually inner and outer tie rods if no play ya check balance when was the last time you replaced tires and had them balanced. check for cupping on the inside of your tires too. cupping is when the tire deforms and develops waves. you can run your finger tips across the inner edge and feel bumps, high and low points along the tire, indicating struts may be going soft and balance.