Hey all,
When i picked up my CS earlier this year I noticed a significant vibration at freeway speeds and had my shop do a wheel balance that helped but I don't think totally corrected the issue. The PPI didn't show any bends in the rims. We put new pads on older rotors and now after a couple thousand miles there's a significant shimmy/shaking in the steering wheel upon braking over 40mph that is less pronounced under hard braking. I may be able to feel it a little in the pedal, but mostly in the steering wheel.
I didn't do any bed-in procedure when the new pads went on, but did try to do it since the vibration started hoping maybe there was some pad residue left on the rotors that might burn off. Isn't this typically called a "warped"
rotor
but really is just pad residue on the rotors causing an uneven surface?
Porsche rotors
aren't supposed to be turned, isn't that right?
What is my best option here? Should we start with new rotors, a good bed-in with the nearly new pads and see what that does? Or maybe a combination of things with a better wheel balance. I've got a
Fabspeed
exhaust
going on hopefully this week and I'd like to get the vibration taken care of at the same time, I love the car but that's a pretty unnerving feeling.
edit: The car is not a DD and I do plan on starting to do some autocross and/or track days shortly and I am under the impression reading here that the OEM pads should be plenty good for what I'll be doing
I'd guess warped
rotor
. Replace with new.:cheers:
Yes as Budman says, more than likely warped rotors so long as you are happy that you've given them a good work out to bed the pads in.
I would think it would be very hard to warp a
Porsche
rotor
on the street. Any sign of heat coloring? Put a dial indicator on its run out. You didn't indicate the mileage of the suspension components. When you change brake pad design you can always clean up the rotors with some 400-600 sandpaper.
Rotors don't warp, except under very very extreme conditions. If you feel a pulsing under braking it's due to either uneven pad deposits on the face of the
rotor
(most likely) or perhaps a
rotor
that is not properly mounted flush against the wheel hub (less likley). You may be able to get rid of it by bedding the pads against the rotors, but if the situation is extreme this may not help. Much of it depends on the particulars of the formulations of brake pads that the
rotor
has been subjected to. I had a similar sitiation on another car (
Audi
S5) and ended up having to swap out the rotors for new. If you're at all handy this is not a difficult job to do, and rotors aren't all that expensive.
"Rotors don't warp, except under very very extreme conditions." Are you referring to
Porsche rotors
when you say this or rotors in general. Just about every SUV I've owned has gotten warped rotors and many of the sedans I've owned have as well. Please clarify your statement.:cheers:
The car has 57k miles, I bought it around 54k so I can't say exactly age of suspension but let's say 57k miles. Car seems to track pretty straight.
It's my understanding that warping doesn't really ever happen on rotors - they just become unevenly worn or have brake pad material deposited unevenly on the surface
I tried 5-7 firm braking attempts from 50 down to 10ish and that didn't seem to burn off any residue, or at least didn't solve the problem
When the PPI was done they noted it was very close to needing front and rear pads and will need rotors soon so I am assuming there's not much life left in the rotors even if they weren't pulsing.
Right now the plan is to have my Indy look at it on Wednesday when I get my
Fabspeed
installed and probably will end up doing rotors just to start fresh
OK...I did some research on this and for the most part, apparently rotors don't or very rarely warp. They can and do wear unevenly causing low and high spots but what has for as long as I can remember, been called "warping" is inaccurate. I guess it was just easier for mechanics and dealers to try to explain the problem this way. On one occassion I actually went away from oem rotors which went "warped" every 5,000 miles to a higher quality after market
rotor
which lasted 50,000 miles before the problem occurred. Regardless, it apparently still wasn't warping. Geeezzz. And the term is still used every day.:cheers:
Actual physically warped rotors are almost unheard of these days. Uneven pad deposit causes
rotor
judder that many "feel" are warped but a quick turn on a lathe dispels this idea quickly as cutting is completely uniform across the
rotor
. Attempt to bed the pads and if that doesn't work just put fresh rotors and pads on. They are not terribly expensive and will return your car to smooth braking again.
Allowing a 5 minute cool down period before stopping the car after heavy braking use will usually prevent
rotor
rudder from pad transfer.
What is the concensus on turning
Porsche rotors
? I thought that was a no-no and they need to just be replaced
For the cost of turning your rotors, you might as well have just bought a new set.
maybe i should stick on a package deal on em tomorrow...
Lemon
ill give you the last schnell special ..
if you call me tomorrow..
Lemon
Just replace the rotors. There are OE brands out there that would cut the cost down quite a bit without sacrificing much of quality.
