Fellow G35ers,

Yesterday when braking suddenly at speeds around 65-70, I could feel the brakes pulsate and the steering wheel vibrate. In my limited auto experience, this normally is an indication of rotors that need to be resurfaced or completely replaced. When driving on normal city roads, this doesn't happen. Only at highway speeds when braking suddenly.

Any input you can provide would be helpful.

 

your correct. Most likely your rotors have uneven wear and the pulsation just isn't that noticeable at lower speeds.

 

Thanks. Do you think it's better to get them resurfaced at the dealer? I've had bad experiences with "specialist" brake shops.

 

Before you do all that, try going out on a back road (no traffic) where you can do some hard stops and then travel for a bit. Sometimes it's not always a warped rotor so much as pad residue transferred to the rotor under a hard stop or two in the past. It's a free fix if it works and might correct the problem. Sort of like breaking in new pads (called burnishing), go out and do a 50-60 mph hard stop down to about 10 mph and immediately let off the brakes and drive for a couple minutes to cool the pads and rotors down. Do that 3-5 times. On the last time, immediately get back up to normal road speeds and go for a smooth ride where the brakes can get lots of ventilation. The object is to not come to a complete stop until the pads and rotors are cooled down from the hard stops. This basically uses the pads to scrub the rotor and peel off that transferred pad material (if that's what it is). If that doesn't fix it, get the rotors turned.

 

warped rotors ..

 

if someone that works at the shop you take your car too cant machine rotors correctly then they need to find a new job and you need to find a new shop lol machining rotors and brake work (aside from drum brakes) is some of the easiest jobs you see in the automotive field.

 

Alright...I may be lame here, or Captain Obvious.

Are you describing Anti-lock brakes?

Back in the olden days, we used to have to pump our brakes. You brake, ease up, brake, ease up. Otherwise, you lock up the tires and skid all over.

Anti-lock brakes do this pumping for you (after all heading straight into a wall, people just put there foot through the floor anyway).

I think anti-lock brakes feel like the exact pulsating you are describing. It feels like you are braking, then not, then braking. That is what keeps them from locking.

Highway speeds and slamming the brakes would be cause for this.

OK, I read it again. I guess if you feel it in the steering wheel, I understand why people are making further suggestions. I do question if that part is in your head.

Good Luck and update this thread,
Dave

 

Hmmmm. I've been having a similar problem as the OP. I was figuring on just replacing the rotors, guess it wouldn't hurt to try this first though.

 

Wouldn't hurt. Free attempt. I read this some time back on a site referencing brake repairs and such. Many think they warped a rotor from hitting them hard at one time or another. Some instances it's simply the pad got hot enough to soften and transfer some of the material on to the metal rotor face. When normal braking, you would feel that extra pad material passing by the actual pad, thus feeling a "wobble" of sorts. Then you pay someone to true the rotors when all you needed to do was simply do this procedure to clean the rotor face.

 

"Officer, no no you don't understand, I was merely trying to get the pad residue off of my rotors"

" Sure, please sign here"

 

^LOL. That would be just my luck!

 

hi guys, new here, i just had the same problem, and just cleane the rotors and put a new set of breake pads and magic, now they feel like new.

 

Thanks for all the input. Is it likely that it's my front rotors? I am thinking of potentially doing this myself. What tools would I need? My pads are ok as the dealer checks them every time I go in for an oil change.

 

personally i would never change just pads or just rotors. Your brakes wear at different areas and levels so just changing one might not fix the problem. To remove your front rotors all you need is a breaker bar, the right sized socket to remove the 2 caliper bolts and some type of c-clamp to push the piston back into the caliper for re-installation.

 

That won't help get the rotors off. You need to get the caliper bracket off before the rotor comes off. 14mm for the caliper bolts. I think it's 21mm for the caliper brackets in the front and 18mm for the brackets in the back.

If his pads are smooth (no deformation), turning the rotors and reusing the original pads should be fine so long as you use sand paper to scuff the pad a bit. But if you're changing the pads, you should at least resurface the rotor. You can get away with scuffing the rotors too unless the old pad dug grooves in the metal.