Resurfacing Brake Rotors - Page 3

ezhangin · Aug 22, 2004, 05:40 PM

I don't know about you guys but I had a bad case of steering wheel vibration, really bad. Variance was .015 and .009. Once I had the rotors resurfaced (under warranty, mind you

), the steering wheel vibration simply disappeared and the car is now smooth as butter when braking.

Evo D · Aug 22, 2004, 06:32 PM

Infantsam-I think your analysis sounds logical in general, but it doesn't seem to apply to my situation, since the shimmy went away immediately, no unusual braking at all. I have a stretch of road quite near my house where I can brake from 70 or so, a condition that would have produced the shimmy which had been quite obvious (while I didn't actually measure it, the severity of the vibration was such that any given point on the outer edge of the steering wheel was easily oscillating back & forth a good 3/4 on an inch, if not more). Also during this most recent shimmying prior to removing the wheel & measuring the run out I had tried some fairly aggressive braking, which had no effect. I have always felt that the steering wheel shake came about due to the brakes not applying evenly side to side on a momentary basis. Like the effect you'd get it you just applied the right front brake. The wheel would jerk to that side, as would the car. This is more extreme than what would be produced by variations in rotor thickness/flatness, so in these cases the effect is not as severe. I never felt the pedal pulsation in any car, though I have had the shimmy in other disc brake cars. The only other relationship (other than the possibility of the rotor to hub) which conceivably was altered (almost certainly) was the position of the wheel (i.e., in relation to the lugs). You have a 1 in 5 chance of getting the wheel back on in exactly the same position (since there are 5 lugs) so odds are this changed. It's not inconceivable this had an effect, though I doubt it.

Dan

rraulston · Sep 3, 2004, 12:05 AM

i think the shimmy in the wheel is caused by the pads "grabbing" the rotor. I had a truck that did this very bad. After everyone in the world tried to fix it, my dad discovered that the brake cylindar was very occasionally dripping brake fluid on the rotor. This would cause the brake to grab and ever so slightly move the steering wheel. If you hit your brakes and the steering wheel vibrated left to right, then they are grabbing. Now if you dont have a leak, then somthing else is creating sticky spots. Maybe the pads. Ime gonna use a scotchbright pad on my 4" and scuff the surface of the rotor. If the shimmy goes away, then there were sticky spots on the rotors. If it dont, ill cut them and try different pads. Ill let you know...RRR

Steve@Evolution · Sep 4, 2004, 09:15 AM

My car have around 5k miles and it vibrates pretty hard during high speed braking. I can feel the pulsing during slow speed braking on the pedal. Since the pads are still brand new, I had the rotors turned at a friends' work place and sand the pad slightly with 180 grit paper. Now the brakes feels brand new again. That is what I usually do first to fix the vibrations on brakes due to uneven pad deposits. I refuse letting the car touch by mitsubishi technicians.

Jason8 · Sep 4, 2004, 10:29 AM

Knowledgeable brake gurus, I need your help.

After my 5 track-day of the season yesterday I started hearing some god-awful grinding from my brakes & could feel it through the pedal. So I aborted my last session and went directly home, very loud grinding accompanied me the whole way.
Long story short… I had worn my inner front pads on both sides down to bare metal… I mean no pad whatsoever!

As a result the inner rotor surface on each side got scored up pretty good from metal grinding on metal. Were talking hundreds of tiny groves of varying thickness and depth (kind of like a vinyl record but worse). However, none of the grooves are even close enough to pass the penny test that Timzcat mentioned. None seem to even be as deep as the border that frames the penny. Do I need to resurface? Could I just sand it down myself with a long level sanding block? Again, we are only talking about the inner rotor surface on each side. The outers on both sides seem to be just fine… just normal looking wear.

Also, what is the correct torque spec for our wheels?

TIA,
Jason

umiami80 · Sep 4, 2004, 02:16 PM

Ok he is the deal, my Evo is about to wear out on the breaks. There is NO shaking or shimmy, stops just like it did the day I got it, it NEVER had a problem. Looked @ my rotors today, they have minor grooves in it. Looks like the rings of saturn, very slight. I hear this is normal ware of the pad.

I have 32,000 miles on nmy car.

DO I NEED to RESURFACE MY rotors? Is it necessary? WHY or WHY NOT???

Thankz...

Jason8 · Sep 8, 2004, 12:42 PM

Okay- the brakes have been replaced with OE. I got a decent deal and they had them in stock so I did not have to be without the car waiting for them to come in. The cool thing is the OE's come with the lube, so you don't have to get that separately, and there has been no squeaking whatsoever. However, I still plan to get some track pads for track days though.

I would still like to get the correct specs to Torque down the wheels. I suspect that may be part of the reason the I had uneven wear on the inner vs outer pads.

Could someone please post the correct Torque number for our lug-nuts?

TIA,
Jason

Z1 Performance · Oct 9, 2004, 06:57 PM

Jason - I'd have to consult the manual, but most cars are around 70-80 ft lbs per lug

feldguy · Oct 27, 2004, 09:18 PM

I passed this thread and have some thoughts on this.

I read Stoptechs sight the day that I had scheduled to go and get my rotors turned. I cancelled, went out with some 150 grit sand paper, brake cleaner and went like hell on the rotors. I took their sheet printed it out and went and bedded the rotors properly. Problem stopped. Apparently a "warped" rotor is a myth, and brake guys dont seem to know their ass from their elbow. I work in a service business and know when people are bs-ing me, and my former brake guy told me I was crazy and that my rotors were shot. He told me all types of nonsense and all types of useless info because he wants the 1000 bucks for 4 new rotors, when I could fix the problem with a 4 dollar can of brake-kleen and sand paper.

feldguy · Oct 27, 2004, 09:20 PM

Correct spec should be 80 lb ft. I have had my wheels come loose on me, so I go up to 95 lb ft without any issues. Mind you, I used a digital torque wrench and carefully monitor the process, as I work with tires. I'd suggest you keep your hub and rim seat very clean, as I have had "issues" in the past with this.

Mark T · Oct 28, 2004, 07:53 AM

I was having the steering wheel shake problem with the stock rotors and pads at 20k miles. I purchased Racing brake rotors(machv) and ferrodo ds2500 pads(raceshopper). The problem started again almost immediately. I have retorqued the wheels twice, re-alinged the car and changed to my winter tires which were rebalanced. I am completely frustrated.

tsi90awd · Oct 28, 2004, 08:14 AM

Mark - Did you bed the Ferrodo pads as stated in the instructions?

My opinion is that a lot of the "warping" that has been reported on EVOM is from not bedding in the pads properly. And this includes the stock pads. The stockers are high performance pads that should be bedded similarly to the Ferrodo instructions. Brembo used to have bedding instructions on their site, but I couldn't find them last time I looked. The "breaking in" instructions that Mitsubishi provides are not suitable.

I went through 4 sets of stock front pads before they got very expensive earlier this year. I bedded them in properly and had essentially no problems with pad transfer. Same goes for the three sets of Ferrodo 2500 pads that I used this year.

Of course, YMMV, but proper bedding-in is very important with the large pads that are on the Evo.

Mark T · Oct 28, 2004, 09:07 AM

I did follow the bedding instructions that came with the pads.

Gumpy · Nov 13, 2004, 08:02 AM

I have had the rotors re-surfaced twice, the rotors and pads replaced with stock ones once, and now again have the steering wheel vibration. I also bedded the brakes properly each time. I only do highway driving. The brakes have never been abused, but for such a performance car they should take a beating with no trouble. Since many of you have switched pads to a different make (i.e. Ferrodo, Hawk, etc) and still have problems, do you think that this could be an actual defect or problem in the brake calipers themselves. Any insight or help would be appreciated.

Gumpy.

machron1 · Nov 15, 2004, 04:25 PM

Quote:

Originally Posted by bukhumnoi2000

I'm going to get new pads .. I have not decided yet but maybe project Mu or Ferodo 2500 .. I am thinking of just replacing the fronts and resurface the rotors.

I don't abuse my brakes but it seems that some who do don't have this problem. It's one of those things that is hard to troubleshoot down to the root cause. Some of the cause are.. defects in the manufacturing, pads, owners washing their brakes while hot or drive through a puddle while brakes are hot. Over torquing lug nuts, installing after market wheels that does not allow sufficient cooling of brakes....

In our case... I will start off with just replacing the pads and resurface the rotors then if that doesn't fix the problem I will replace the rotors and the pads again.

If you buy the Ferodo DS2500s they will resurface your rotors for you believe me. After about 1,000 miles my rotors were smooth as hell.