rear brakes fail before front?

[KuroNekko]

Mazdas are also known to have heavy rear brake bias. The Mazda3 rear brakes go out fast and it's also seen with the Mazda6.
Interesting how these above-average handling FWD-based sedans have heavy rear brake bias.

[SamirD]

I believe it is 105.

I set mine to 103ftlb.

I just looked this up in the owners manual and I was wrong and WESHOOT2 got it. It's 103.3 or exactly 140Nm.

[ProMarinero]

I'm also finding my rears seem to be wearing faster as well. However, I found another interesting bit. When I changed the snow tires to summer skins I gave the brakes a good look. The rears had been making a funny scraping noise for a little while when backing up and/or cold. I checked the rear pads and found them literally rusted to the caliper groove. They wouldn't back off once the piston released so the scraping seemed to be the pad sticking overnight when parked. I had to pry them out, wire brush the rust off the pad ear and even slightly file down the ear just a hair. The fronts were also extremely tight but not rusted.

My car has a little over 50k miles and does 95% highway commuting of 200 miles a day, three times a week. 4-5 months a year of that commute is spent on snow-treated roads (magnesium chloride) so I'm guessing the tight pad clearance was extra susceptible to rust binding.

Bottom line - check your pad ear/caliper groove clearance and use a tiny bit of grease to keep it free and clear of moisture. These fit tighter than any other car I've worked on - too tight in my opinion. A little bit of material filing won't make a difference if necessary and will allow the pad to back off better.

[bootymac]

Ugh, that's annoying. I wonder if painted calipers will help?

[hartmelody]

On most cars, the e-brake adjusts the pad clearance on the rear brakes. Using it a lot can result in them being adjusted a bit too tight and premature wear on the rear brakes.

Question- I have absolutely never used my e-brake at all. Are there other causes for the rear brakes being too tight? I found the outside shoe to be almost completely worn away, while the inside shoe still had quite a bit of surface still left. Could there be another issue causing the outside shoe to remain in contact with the rotor when not engaged? (sorry for the lack of technical expertise here, but this just seems to be a strange wear pattern to me.) Also, my front brakes are barely worn at all so that fits with the idea that the rear usually goes first. 33K miles on my 2012 Kizashi, and at least 20K are highway miles. I appreciate any help/ideas.

[murcod]

Sounds like another case of them seizing and the caliper not "self centering" correctly? I assume you live where it snows and they use salt on the roads?

[hartmelody]

Yes, I live in the land of ice and snow so that's likely the issue. Also interesting, the driver side pad is worn completely down while the passenger side still has 3mm left on the outside shoe.

[KuroNekko]

Not sure if the pads were already replaced, but grease those caliper slide bolts.