want.turboII.S5

ok so i know my front rotors were warped, my brkae pedal was pulsing really bad at anything over 30mph, and could even feel it lower speeds, like coming to a stop i could feel the whole car actually jerking a little bit. i relpaced the front rotors, and it helped. there is hardly any pulsing at high speeds actually, but can feel it more at like 20-30mph. could this just be my rear rotors? i did not replace those. or could it be something else? i know this isnt really rx7 specific but i wanted to get direct answers, i have googled and found all kinds of stuff. maybe someone else has experienced before. thanks

lduley

iTrader: (1)

If i were you, i'd be replacing the rears next. Are you only feeling it while braking? Or at all times?

Sgtblue

iTrader: (16)

Probably still some run-out on the rear rotors. If they've never been turned it's likely you could get them trued up instead of replacing if your budget's tight. Even some of the chain parts stores have laths these days. I would also check the hat surface and hub faces on ALL FOUR corners to make sure they're clean and smooth.

misterstyx69

iTrader: (142)

pads should be replaced when you do rotors..did you do that too?

Ricebox

iTrader: (3)

everytime I do brakes I do all 4 pads and rotors, id do your rear rotors at least as well.

Turbonut

iTrader: (1)

Rotors don't warp, it's just pad deposits on the rotor, put for a test:
As the rears use the pads when ebrake engaged, pull up while slowing
without your foot on the brake pedal and see if any abnormality is felt.
Also, when doing the job, did the piston(s) recede into the caliper easily,
or was there resistance? When driving, either front rotor excessively hot?
Nice to check them, or all 4 with an infrared thermometer.
If single piston, caliper pins able to move easily?

Sgtblue

iTrader: (16)

Not so.

Turbonut

iTrader: (1)

Care to elaborate?

Over my lifetime I've never seen a brake rotor warp. Actually if you read the Stop Tech articles,
they've never seen one either.

On our '08 knock-around car with now 249k miles, I've used metallic pads many times to clean
up the rotor. Before our yearly trip down to Florida in Sept, the brakes were doing their normal
pulsation, so in August I installed the metallic pads I keep in the garage. In 2 days of normal
driving, the pedal was smooth, no pulsations. Installed the ceramic once again and no
pulsation since. Be going back North this weekend and still good to go.

Might want to peruse the following:
https://www.zeckhausen.com/catalog/i...Path=6446_6444

Sgtblue

iTrader: (16)

How do you define warping? The metal, particularly on the less expensive (Chinese) rotors is not uniform. There are areas that are harder or softer than surrounding areas and that difference is exposed by high heat or agressive pads...or both, causing uneven wear. Rotors aren't bending but become warped...or if you prefer...develope runout. All it takes is a thousandth or two. Exacerbated by uneven mating surfaces between the hat and hub, corrosion and by glazing.

Turbonut

iTrader: (1)

Not to be smart, but the definition of warped is to bend or twist out of shape, especially from a straight or flat form, and the rotors will not experience this phenomena.

Use a dial indicator on the outer edge and find there is no run out, then check the pad wear surface and the difference can be seen.

Pulsating occurs not only on as you state, cheap Chinese rotors, but will also occur on more expensive aftermarket and OEM rotors, at least in my experience.

Whether mechanics know the difference or not, it's an explanation they have used for years, and so has most everyone else.

Sgtblue

iTrader: (16)

I said particularly on cheap rotors...not exclusively on them. But ok...you got me on the dictionary definition of "warped". Regardless, in my experience wave-like high and low spots develope over time which are IMO understandably described as warping. Maybe manufacturers like to split that hair but the effects...and cure, are the same. And yes, runout is to be expected on the wear surface and not on the edge.

want.turboII.S5

thanks everyone i will have to check everything mentioned here

DWNUNDR

iTrader: (1)

when I had my shop I had brand new out of the box rotors that were "warped" but as stated typically its pad deposit

if you feel the pulse in the pedal it doesnt mean its the fronts unless you typically feel it thru the steering wheel too... Id say go thru the rears next

Gab

Easy and quick test is to pull up the e-brake slowly at a slow speed (<25) - if the rear rotors have pad deposits, you should feel pulsation as the car slows down when you apply the e-brake.