F Monster

My friend was looking at my tires earlier today and noticed that my brake pads were wearing at an angle. He was also shocked to learn that these pads have only 6,000 miles on them. We looked at the old front brake pads my mechanic replaced and they are not showing any wear like the current pads.

Below is the old pad that came off the car after 30,000 miles:




This is the pad my mechanic installed on my car, after only 6,000 miles



He also noticed some odd wear on the rotor - evidenced by the vertical lines across it's radius. He thinks it may be related to the problem with the pad. He also recommended a different mechanic...

Is this wear considered normal? We looked online and some people reported similar wear, but nothing we found was as extreme as this. We will be looking at it on a lift on Monday to get a better idea of what is going on but I'm curious if anyone has an idea what it could be in the meantime. Any help appreciated

I8ABMR

mine are the same way and from the looks of you rotors with the pad dust filling the drilled holes, you know why that thing is wearing all weird
my front pads have turned white at the edge . I am going to kill them at WHP Main next weekend. My front pads were replaced in October and are ready to go in the next few thousand miles. It will be less than 7k also. It is what it is . We have to pay to play. I have also killed 4.5 sets of tires in 2 years

Ill try to take a pic for you

F Monster

Yeah if you can take a picture for reference that'd be great. Killing 4.5 sets in two years is crazy, but then again you're literally tracking your car every other month it seems.

I8ABMR

Here you go buddy !!

Next week will be the 15th track day in 2 years ( and 11 days )

I8ABMR

Bro there is no way your drilled holes would be packed like that if you were driving normally . Mine look like that when I come home from the track

F Monster

I definitely do not push this car at all much less track it. So there's gotta be something wrong now that you mentioned it. Also my brake pads seem to be wearing off at a sharper angle than yours.

ABMR

I'm his friend, he babies this car and it has definitely never seen track duty. It is lucky to see over 70 on the highway...

The pads were last replaced at a trusted mechanic but one that mostly had experience in economy cars. I'm wondering if they did not have the proper tools to compress all the pistons in the 6pot brakes and they rigged something improper for the inner 2 caliper pistons, damaging them in the process and causing them to stick during operation. Mechanic must have figured since the pad was installed it would work, so he did whatever method he used on the other side as well. The wear on these pads indicates to me that the pad is almost hinging on the lower pistons. I am going to get them off Monday and take a look. I'm curious for any input on this theory

Are caliper rebuild kits available for these cars?

A critical piece of information for me is that with his driving style the old pads wore completely flat...

I8ABMR

That is odd then I drive my car hard and am used to the pads and tires going and for obvious reason. I would wait for some of the other guys to chime in. The only time I ever see my rotor holes filled like that is when I have beaten the hell out of the car on the track or have done some repeated 120 mph stops. And when it fills up like that it makes a low speed grinding noise unless I open those holes with a little tool I have

Its a riddle, wrapped in a riddle, surrounded my an enigma.

Im sure one of the F'ers with way more technical knowledge like me will chime in in a minute.

SoulFreak

iTrader: (1)

I'm thinking it could be a few things. For one, Did you replace the rotors and pads at the same time? If just the pads, the pads weren't bedded in correctly. The wear on the rotor and the pads haven't mated together. You're going to have to bed them in again. It can be a contributing factor for uneven wear. Two, yes when you get it on the lift on Monday check the Pistons like you mentioned. The process to remove and replace brake pads ain't difficult for these cars. Many mechanics that don't follow directions can screw it up. Make sure your shims are installed. What compound are the brake pads? It doesn't matter but I'm curious?

flowrider

iTrader: (9)

Hey Guy

I sent you a PM. Have you installed the headers yet?

Lou

I8ABMR

Hey thanks for the explanation Soulfreak. My pads were installed with new rotors in October, but because my pads go frequently I often change them out with an older rotor. . I will have them check the pistons when they do the next set. Im going to kill these pads next week at Wild Horse Pass ........and my front and rear tires Then will retire her for the summer months. Going to do a fresh set of tires, new front pads, and a new windshield.....and a wax and polish. Going back to Clark Kent mode until October

SoulFreak

iTrader: (1)

You're welcome Tammer, my name is Nestor. Yeah, it's very understandable to keep current rotors with a new set of pads. It's not cost effective to throw away perfectly good rotors, but it's highly recommended to replace rotors and pads at the same time. This will eliminate uneven wear issues, noise issues, and will ensure optimum performance. There's nothing wrong keeping current rotors until they get below spec but you're eventually going to run into those issues. As mentioned above. Also proper installation of these components is a must, but then again shim and pads only go in properly one way.

SpeedFreaksUSA

iTrader: (1)

Something is definitely wrong but I need more info to try and figure out what might be causing it. Do you have photos of the inside pads as well? Are they worn unevenly in the same fashion? Tops worn much more than the bottom or vice versa?

The vertical lines are just pad imprints. It's usually cased by coming to a complete stop with brake pressure still applied while the pads are hot. You say you don't drive aggressively, if that is true then it looks like the pads are dragging and causing heat buildup even with your foot off the brake pedal.

Also it may be a silly question but I want to be sure you still have both of the the guide pins and the spring in the top of the calipers and everything is properly installed, correct?

-Matt M.

ABMR

We do not have any pictures of the inside pads yet, owner didn't let me take the wheel off to inspect further (he read something on here about one guy whose wheel came off while driving, and now he thinks removing/reinstalling wheels is a specialty job). And to touch on something a few of you mentioned - I do not think the rotors were turned when the pads were replaced, though they certainly should have been. And improper bedding of the pads will not cause wear like this... they may wear prematurely, and they may squeek, it may damage the rotor... a lot of things can happen when pads are not bedded properly. But as long as the caliper is doing it's job it should be pushing evenly across the pad and if everything else is working there is no way for a pad to bed in such a way that it produces wear at an angle like that.

The vertical lines are indeed pad deposits, I think what happened there is the pads were not designed to wear at such an extreme angle and doing so damaged the pad. The picture shows it slightly, but its very visible in person - the actual fibers of the pad material are starting to disintegrate - looking along the edge of the pad surface you can see loose fibers, almost like hairs sticking up. The old ones do not do this and I'm wiling to bet that once removed, these pads will have an uneven gritty texture to them due to the improper angle at which these wore. This would also explain to me the short period of time in which they wore down.

Guide pins looked installed correctly to me but admittedly, my cars are mostly '90s through early '00s BMWs and the calipers I've worked on are not set up like these. I did inspect them though as I was curious if they could be the problem but they seemed firmly in place with no odd movement and they looked like they were installed properly, to the proper depth. Bad guide pins/pin installation to me would indicate something more like erratic braking behaviour - aka the pad moving around under braking, particularly partial braking, likely causing shaking or shimmying under braking.

Just as a note as well (to my friend, mostly) lot of cars have beveled pads - but pads are not designed to wear into a bevel. Cars with bevelled pads are normally designed to prevent squeek and assist the bedding process on high performance brakes, so that as the pad wears it beds itself in naturally until the full pad material is contacting the rotor evenly. So essentially pads that come bevelled are designed to work themselves into a flat shape. Like these for example.

The more I think about it, the more I think it must be the inner caliper pistons damaged. I'm willing to wager that the inside pads are worn the same way, due to the mechanic using the same improper piston compression method on the inside of the caliper. I honestly don't see any other way for both sets of front pads to be wearing like this.

I8ABMR

Thanks for explaining that, Nestor. Right now I have a bit of squeaking when I come to a stop but next weekend will be the 3rd track day this month and like the 6th in just a few months. I am going to do a couple of sessions on these pads and take her in for new pads and a new set of tires. I will bring the uneven wear to the attention of my tech and SA. I know they are going to give me some *** explanation. I will mention to check the pistons. Thanks again Nestor