Chrno

umm.. this is gabe the penguin.. my account has been inactive so im using chrno's (the xb poser) jp jp.. well i had a question about the brakes.. my brakes have been making a grinding noise coming from the front driver brakes.. it started happening when i touched 13k miles.. about a week ago also.. i checked them out visually but i havent had it inspected because im asian and im cheap.. when i took a look.. the surface of the inside rotor was shining.. i touched it and it wasnt smooth.. my grinding has been coming from the rotor.. but i dont know what my situation is.. my friends have suggested me to bleed my breaks due to the pressure or my rotor is warped.. does anyone have any experience with the break problem like this? i was wondering if anyone knew any suggestions for this on how to go about and fixing this.. thanks
marks a loser..

oh yeah.. i also posted about my tranny in 3rd gear.. i have a f*cked up scion.. stupid scions.. jp jp.. but yeha.. my car is definately a monday car..

Sprockett

Should be covered under warranty, shouldn't it? If so, just take it to the dealer and have them check it out and fix it for free :D

djct_watt

Any excessive or hard braking? Like panic stops. . . or hard braking from 90+mph, driving an auto with both feet (premature brake wear)? If so, your rotors are warped. If not, I can't imagine rotors wearing out that fast. . . perhaps your pads are nearly gone? I'm not sure if bleeding the brakes will help. . . I would get it checked out.

If it's neither the rotors nor the pads, it should be covered by warrantee, but 13k miles is plenty to punish a brake system, and I can't see them giving you warrantee for that, unless you really know how to make your case. It's like going out and doing brake stands, burning all your rubber in 100 miles. . . they are not going to replace the tires. Now I'm not saying that you did wear your brakes out due to abuse, it's just hard to attribute those kinds of things to defects in the car. . . especially at 13k miles (not a ton, but not insignificant either). Either way, it's worth a shot.

boilerman

I had problems with a Jeep which caused noise and eventually locked the front wheel to the point that I could not turn it by hand. Happened every eight to ten thousand miles. The seal O ring would seize to the piston and the piston would not retract. I rebuilt several times with both metal and composition pistons but finally replaced the entire assembly and had no further problem. I think perhaps the bore was too tight for the piston. I did not have any problem with the rotor warping. Some scoring. That rotor was made by people who make Detroit iron. Not a thin thing.

LeeD

1. Your rotors are NOT warped. Grinding noises are not an indication of warped rotors. When applying the brakes hard and your steering wheel shimmies from side to side violently is an indication of warped rotors.
2. Bleeding the brakes will not help a grinding problem or any problem giving any noise. That's just the way brakes works. I'm not going to explain why if you don't understand. Buy a book, or google the internet.

If your brakes are making a grinding noise when applying the brakes, something stronger than the pads are hitting the rotors. Period. If you take your wheels off, and look at your rotor face front, back, and side where the vents are, you should be able to see the scratch marks. How clearly depends how strong it's grinding and probably how loud the noise too.

Either,
A. The pad backing because you've worn through the pads. Possible at 13k. If they are the stock pads, then the squeel indicators should be hitting the rotor and squeeling loudly BEFORE you've worn through your pads. Although it's possible you've warn through your other pad quicker due to a sticking caliper piston (squeel indicators are not on each pad). Happened to me before.

B. Something like a rock, pebble, or somthing else got stuck or wedged between the pad and rotor and is grinding away at your rotor.

C. Or something else in your caliper assembly or some other foriegn object has gotten loose/broke and has gotten itself wedged inside your caliper assy and is pushing against your rotor. I've seen this before.

D. Your running some high end race grade pads in cold temperatures. These sound like metal on metal when at cold temperatures. I've seen this before.

Xcalibur1986

Maybe it's the ABS?

LeeD

How?

ABS only removes the brakes by dropping the fluid pressure, then reapplying the fluid pressure cause the brakes to grab again. Worst case is that it doesn't and the pads drag, and they should make any noise different from when you apply the brakes normally.

hence, options A,B,C,D.

Back_In_Black_xA

I would suspect your brake pads. So far at work I have seen 3 xAs with less than 15k miles on them have to have the brakes replaced, two of those were under 7k. Toyota seemed to throw some ____ ___ pads on these cars. A Camry can go 35k-40k before it would need brake pads.

LeeD

Take a look at the pictures I took of my stock pads when I took them off with only 2k miles. You'll see that they aren't really a full pad, but have been shaved some.

https://www.scionlife.com/forums/vie...608&highlight=

djct_watt

I did a panic stop from 160mph, in a 4,500lb Lexus. . . no joke, trust me, the rotors were warped and the the grinded and vibrated. Maybe "grind" is not the right word, but most people who rode in my car (at that time) said that it sounded like "grinding." They could just be stupid, but you're right that it was more like vibration, with a helluva lot of noise. The "grind" or whatever you want to call it, in my situation, was most prominent in the last few seconds before coming to a complete stop, or also when braking at slow speeds.

So it is POSSIBLE, but it more than likely is the pads.

Oh yeah. . . good point about possible foreign objects stuck in the brakes (happens).

LeeD

Braking from very high can make sounds like that if you continue braking to almost a stop. I've heard it myself many times.

To give you an idea of warped rotors, the first time (~8yrs ago) I took my Z out to the race track, stock pads/rotors/fluid, I faded the crap out of them and warped the rotors after doing repeated 110mph to ~30mph stops every ~1min for 20min straight for 4x 20min sessions.

How did I know I warped the rotors?

When I was trying to heel n toe downshift while braking, the steering wheel would vibrate so much, I couldn't even take one hand off to down shift.

That's a sign of rotor warpage, not grinding noises.

Because of the warpage, (imagine your rotors now look like a paper chip) at certain radius there will be more grab than others. Because of this, under braking, and the rotors rotating, the brakes on the right side will grab at different torques, at different times, than the left side, hence causing the steering wheel to wobble. The left grabbing more than the right, then vise versa.

Regarding the noise, just about any car's brakes will make that noise when stopping from very high speeds to a very slow speed. It's very likely the results of the pad's Coifitiant of friction changing due to the extreme heat buildup. At very hot pad temps, you will frequently hear that noise. You hear it all the time at track events and sometimes at autox's. It's not an indication of rotor warpage.

A wobbly steering wheel or an inconsistant deceleration with a constant brake peddle force is an indication of rotor warpage.

In the many years and many track days that I've driven, I used to go through a set of brake pads in one day(~200miles), warped numerous rotors, had a few sticking caliper pistons, rebuilt a few calipers by hand, and would melt all my rubber dust boots after every track day from the extreme heat. I've also driven tons of different cars on the race track with different brake setups from stock to 14" 6piston AP Calipers, stock pads to full race, as either a driving instructor or just driving a friends car for fun. Now, I'm not Mister Brembo God or something, but there isn't much that brakes have done, that I haven't seen or done myself. Car/Racing brake technology (along with suspension/chassis setup/technology) is a peticular passion of mine.

An EXCELLENT book on brake technology, that's become my absolute BEST reference for brakes is: "Brake Systems: Oem & Racing Brake Technology"
http://www.amazon.com/exec/obidos/tg...47800?v=glance

Mine is FULL of notes and highlight marks, and brake dust finger prints. I strongly recommend this to anybody that wants to know how/why brake work from OEM to racing and how to make them work well.

djct_watt

I see, that explains why the rotors were black (first production year LS400, notorious for small rotors on a heavy car, no Z rotors there). I replaced the rotors (which were warped), but I assumed the warpage caused the noise, didn't think about the toasted rotors. So I retract my initial post. . . it probably isn't rotor warping, but one of the things it could be is a bad rotor, which needs replacing anyway, if that is the case.

Chrno

hello everyone. this is mark. "Chrno" i have taken a look at gabes XA today regarding to his front driver side brakes. i haev inspected it today and currnetly, i was right his brake pad are so worn out. its grinding metal to metal. so bascially he's going to need a new set of frong pads and a new rotor and the passanger side resurfaced... other then that i'll be sure to keep everyone informed of whats going on with his brakes. Thanks again everyone for the support =)

-Mark
Thank You :D

djct_watt

so did it do that on its own or has he been hard on the brakes?

gabethepenguin

ok this was my post.. heh.. well if you guys must know.. to be honest.. ive probably taken my car onto metcalf abou 6-10 times in the entire 13k miles.. ive slammed on my breaks about 3 times.. one time where i slide about 6 feet after my tires locked.. that was about it.. but i havent done any stunt like that for about 3 months.. and i was driving fine.. but i started to hear the grinding sounds within 3 and a half months.. yeah.. chrno and i checked out the car.. because im inexperienced in breaks and the whole break system but i know how it operates, had to have mark.. the grindage was on the back side of the rotor caused my a worn pad.. if anyone can help me find a pad and rotor for cheap.. please let me know.. im in need of it.. well.. i found that autozone sells their pad for 20 buck online and kragen for 40.. but i dont like kragen or autozone.. and i dont wanna go more on performance slotted discs or pads.. so yeah.. thanks..

gabethepenguin

oh yeah.. the punks at toyota told my my warrenty on brake replacement and brake inspections ended after a year or 12,xxx miles.. so i have to pay for it.. and i need the pad and disc cheap..

gabethepenguin

oh yeah.. the punks at toyota told my my warrenty on brake replacement and brake inspections ended after a year or 12,xxx miles.. so i have to pay for it.. and i need the pad and disc cheap..

djct_watt

cheap? Pad's shouldn't be too expensive. . . rotors? I'm guessing $50 a rotor. . . and if you do the work yourself, you'll save a lot of dough.