aksansai

iTrader: (2)

The previous owner said that he had the rear rotors replaced on my 01 Max, but that the front rotors are original. Inspecting the rotors today, I noticed that the front rotor has no "groove" (where the pad makes contact with the rotor), but the rears do. It's amazing that 114K that the front rotors do not have that groove (still smooth, but as if it is wearing evenly the rotor).

The front wheels get slightly dirty between car washes, but the rears get dark gray with brake dust. I'd imagine that's it is a combination of inferior pad to inferior rotor. Can anyone comment (if they have the OEM rear rotors) as to how much dust they see and if their rotors are also wear-free even given some good mileage?

theoutsider

Sticky calipers?

irish44j

iTrader: (38)

If it's at 114k, it's a good bet that the pads are not original, and may not be OEM, but "OEM replacement." Fronts and rears may be different....

There is nothing "special" about OEM rotors. They are just cast-iron rotors just like base Brembos, frozen rotors, etc.....

P. Samson

The fact that the rear rotors have been replaced and particularly that they've been replaced before the fronts, indicates something not right has occured with the rear brakes. I have OEM rotors and pads and the fronts should and do shed a lot more dust than the rears. On mine the fronts also have no "obvious" worn pad contact area, but I'm sure that if you were to measure the rotor thickness, they would in fact have some wear. The rears have no obvious wear as well, but with mine the rears have some minor circumferential grooving that I don't see on the fronts. It sounds like you possibly have some "hangup" issues with the rears. Check that on a slight incline in neutral, with the parking brake released, apply the brakes and then release the brakes........does the car "roll easily? If it doesn't, check that the parking brake is not the cause. If the parking brake is not the cause then it could be the pads not "retracting" away from the rotor due to a caliper problem. Sometimes when rear pads are replaced by an inexperienced person the pistons don't get "wound in" far enough, and after the "brake job" the pads can't retract away from the rotor for running clearance and the friction puts so much heat into the caliper(s) that the piston hangs up, sticks or seizes. Everything gets toasted including the rotors.

aksansai

iTrader: (2)

The car has no trouble rolling after I release the E-brake.

Intriguing... especially since I've never owned a car with rear discs that shed so much brake dust... I'll check into that! Thanks.

ghostrider17

iTrader: (6)

P. Samson's post is excellent, as usual!

In conjunction with that: have you considered that perhaps the rear pads were replaced with non-oem material, causing more dust?? They don't necessarily have to be an INFERIOR combination.....just not OEM, or the same as the fronts.

I have hawk pads fr & rr, and though they dust significantly MORE than OEM, the fronts still dust 5x more than the rear. As is should be.
I'd say pad wear fr/rr is roughly about the same as the dust output on the wheels as well: rears typically last 5x longer than fronts.
just fyi.
gr

Prophecy99

iTrader: (1)

as said before you got aftermarket pads casuing alot more dust than the oems in the front

<== in the same boat

KRRZ350

iTrader: (29)

I need to add to sampsons post though, seeing as I've seen and been the cause of many smokin' brakes in the past.

Caliper guide pins must be able to move freely. Pads must be able to slide in & out of the caliper brackets, corrosion can & will build up on both sides of the shim, this must be completely eliminated and in some cases the entire brackets warrent replacent. On top of that, replacing a "seized caliper" is not fun when you put the new one on only to have everything drag again because the problem was actually an internally collapsed rubber line.

ghostrider17

iTrader: (6)

...are you talking about the individual brake line coming from the master/res to the caliper???
Please esplain.
gr

aksansai

iTrader: (2)

I am going to chock this one up to poor quality pads in the rear. Which is another excuse to put a higher quality (i.e. OEM at minimum) pad when the rear brakes start to scream.

KRRZ350

iTrader: (29)

Yes, I think I'm talking about the rubber brake hose/line. They can & do collapse internally, and it acts as a check valve for pressure, holding hydraulic pressure between the collapsed part of the line and the caliper, ie it pushes on the brakes. It's a simple enough thing to check for and should always be done before you assume a bad caliper. All you have to do is step on the brakes & spin the wheel to make sure it's dragging, then simply crack the bleeder screw loose & if that allows the wheel to spin freely it is not a bad caliper but instead a collapsed brake hose. Cracking the bleeder screw loose will release the residual pressure that is stuck between the collapsed portion of line and the caliper piston.

spdfreak

I don't think the OEM rotors are anything special. They are decent though, but my sqwealer (on the pad) was able to notch a groove into the rotor, which is something that supprised me because the sqwealer is made of softer material than the rotor.

MichMaxFan

Regarding the rears,

My pass rear rotor can be warm but not hot enough to prevent you from keeping your fingers on it, while the driver rear can be warm enough to keep you from holding your fingers on it - but not so hot to burn you w/ a brief touch. The diff is noticeable, but not "extreme" between the two. The fronts are considerably hotter, as they should be, after use.

I'm thinking either one rear is not grabbing as it should or the other is possibly hanging a bit. So, when coasting to a stop after a drive and I check the rears, they are both cool to touch, indicating no hangups. If I were to jack the rear up and spin the wheels and apply and release the brakes and function is normal, would this be enough to say that there is no hangup w/ the rear caliper? The diff in heat from one side to the other seems odd, but they sure are not as hot as the fronts.

The brakes were just changed all around, and I can't say this wasn't occuring before changing them, but I am more observant just after a maintenance job so that could be why I am finding this issue.

Any suggestions?

skc

Nothing special about the rotors. They just didn't replace the backs in time and they grooved.

jreddington3

A good way to check is to try and find a place where you can travel a good distance without hitting the brakes and coast to a stop using downshifting. Then feel the wheels to see if there is a significant difference, especially left to right, between the temperature of the wheels.

I fortunately, on my commute, can manage on the right days to travel about 6 miles on the freeway, dowshift off the exit, time my way through a couple lights, coast slightly downhill in 1st gear into the driveway at work, and even get into my parking spot, turning off ignition a couple feet early (while still in gear) to stop exactly where I want to be without hitting the brakes once (then setting the parking brake).

After doing the rears last spring I noted that while the fronts were dead cool, my left rear wheel was noticeably warmer than the other three wheels. Took the wheel off that night and added some more lubricant to the slides and exercised it a few times. Next morning, made the lights again and all brakes dead cool. After a couple other morning checks I was confident I had fixed the problem.