Brakes – 2006 Mazda 3 GT Sport – Improper contact.

[W]

Hey ETCG Fans,

I’m hoping to solicit advice from the collectrive minds here, regarding my front disc brakes.

Purchased the car in Jan 2014. Obvious trauma to the rims (refused to balance), and FL brakes. Rims replaced. Brake pads and rotors replaced. Passed safety with no outstanding issues noted.

Over the next few weeks, I was feeling my wheel pull left when braking. Not always. Just…sometimes. And very slight. Ignorable at slow speeds, but scary (and dangerous) at high speeds.

Inspection showed a ring of rust around the FL rotor as follows:
Out-facing: (visible while parked): Outer ring on rotor 25% clean, inner (near the hub) 75% rust.
In-facing: (facing the engine): The exact reverse.

Even with new pads and rotors, the same pattern was appearing. Fast forward a few weeks, hoping for things to settle in, the pattern remains.

Next: Pulled the FL brakes apart (the 4th time) and inspected the caliper. It was physically damaged. Aha! I didn’t do this, I baby my toys. So I replaced the caliper and pads, leaving the old rotors in place (according to the micrometer, they hadn’t worn noticeably, inner edge to outer). For about a week, you could hear a bit of soft grinding as the rust was being grazed off over time. I thought the problem solved.

July of this year, the pattern remains. Except it’s about 50% rust, 50% clean shiny metal now. So, some improvement, but something clearly isn’t right.

I’ve replaced the Rotors, pads (3rd set) and caliper.

2 items of note about the car:

1) When cold, and I’m backing out of the driveway in the morning, there’s a distinct hum coming from the FL wheel. It lasts until I stomp on the pedal (to which I hear a small clunk, guessing the pads are moving.. maybe the shim is damaged from the previous caliper compressing it weirdly?). Sometimes, when I make a left at speed, I can hear a faint humming as well (usually indicative of a wheel bearing failling).

2) I’m also suspect of the ball joint on that side as well. (creaks now during turns, no grease fitting, so it’ll have to be replaced)

Now, my skills at troubleshooting notwithstanding, I lack the experience to piece these items together. Does any of the above point to a smoking gun in the minds of a seasoned mechanic?

I am truly grateful for this forum, and any advice ETCG’ers have to give!

My humblest thanks!

Topic

[college man]

here is a link for brakes and noises.

http://www.ericthecarguy.com/faq/solving-brake-problems

http://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car

[Ingvar]

http://www.autozone.com/autozone/landing/page.jsp?name=brake-job

Look at the table on the right.

If your caliper was damaged, my bet is on bent/damaged pads bracket and pins.

[W]

Thanks Mod. I’ve been through both sections, without much luck isolating.

I’m thinking this through methodically. Assuming there was front-end trauma, what else could have been impacted that would affect braking after the calipers, slide pins, rotors and pads were all replaced with new?

Unfortunately, I can only guess at the next sequence of steps one might perform. I know this isn’t rocket science, there has to be something I’m missing.

[W]

Thanks for your input Ukrkoz.

I did see tapered wear on the old pads, but that was expected given the contact patch visible on the old rotors. The calipers, pins, bushings, rotors and pads .. everything was replaced less than 6 months ago, and yet the rust pattern persists. But will confirm if tapering exists on the current pads tonight.

I believe a new bracket was included with the new caliper? It’s been 2 months since I’ve taken it aapart last. I wanted to see if the wear pattern changed. (I’m still new to this, so please, take my assumptions with a grain of salt :o)

So assuming (see?) all parts are new (Pads, rotors, calipers, bushings/pins – came with semi-loaded calipers, but lubed with silicon paste anyway), I’m baffled as to what could be causing it.

My 2 remaining suspects are:

1) Maybe I’ve lost or damaged a shim?

2) Other – including a wheel bearing or ball joint, but I’ve seen conflicting answers on whether either can have any effect. I know there’s clearly one right answer, but until ETCG says it, I’m really hesitant which to believe.

No issues at all on the other 3 wheels. Installed and functioning perfectly from day one.

[Lorrin Barth]

One thing you could try is swapping rotors side to side to see if the odd wear pattern persists on the other side. If so, the rotor isn’t flat.

[EricTheCarGuy]

As pointed out in the article College man posted for you, it could be a brake hose issue. If the brake hose is faulty, it can keep the caliper applied and cause the noise and the pulling issues you describe. I cover the procedure of making that determination here.

http://www.ericthecarguy.com/faq/solving-brake-problems

Keep us posted.

[Author]

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