What Are the Rear Breaks Used For?

[aarias298]

I know this sounds like a stupid question but, i always wondered what the rear breaks on my TC did. Ive changed my breaks myself once so far and noticed that the front breaks are significantly used up more than the rear. Are the read breaks only used when you pull the parking break? Or when the ABS kicks in? I dont really understand, is there any point in changing the rear breaks if there not worn out? Im almost ready to change the breaks again, im curious for any suggestions on how i should go about assessing the breaks. I also have used autozone (duralast) breaks, im open for suggestions on other pads that i can use instead of these. Should i order them straight from the dealer?

[connman429]

It is true that the front brakes see more load than the rear. This is due to weight transfer. The inertia of the car going forward causes it to nose-down when the brakes are applied, so the front brakes are taking more of the car's weight than the rear. This can cause them to wear faster. If the rear pads aren't worn down by the time you are ready to change the front, then save yourself the money and just do the front.

As far as which pads to use, it all depends on your driving style. If you want performance or frequently see a lot of precipitation accumulated on the roads where you drive, EBC and Stop-tech are, in my opinion, the top two. If the weather is generally nice and you're just tooling around town, the extra cash you will be shelling out for premium pads isn't really worth it. Also try to stay away from pads with a high level of metal in the compound, as these tend to eat your rotors faster.

[CadenceScion]

Most vehicles are 60/40 or 70/30 for breaking.
Get a street brake pad (Ceramic) (EBC, Hawk, Raybestos, Wagner Thermo-Quiet, or Duralast Gold from AutoZone)
I also would recommend EBC, StopTech, Brembo or PowerSlot Brake Rotors (Centric Rotors)

[aarias298]

Thanks for all the feedback, it was all valuable information. I got a tire rotation two days ago at Mavis Discount Tires, and i was told that i needed to replace my front rotors bc they were getting worn down. Im not sure what there supposed to feel or look like. How do i know if there not just bsing me and not just trying to get me to shell out money or being honest? If my rotors needed to be replaced, is it worth spending more money on getting them upgraded to slotted/drilled like i see on nicer cars, or getting a decent priced rotor and staying stock. I drive a lot to school and do a decent amount of stop and go. I see you guys said EBC's. Mavis said i would only need the front, would it work find if i had upgraded front rotors and stock rears until the back ones go out?

[CadenceScion]

I have drilled/dimpled rotors from EBC and from personal experience, they stop and perform much better than OEM. As far as how to tell when your brakes are due for replacing, first of all, inspect the rotor for pitting, any rough feel or excessive rust/corrosion. Secondly, if you press the brake pedal down and you're using more effort to stop, then your pads are getting worn down. Some vehicles have a wear sensor or a sound they make when the pads are due to be changed, it will sound like a high screeching sound. I would highly suggest replacing your brake pads to a street use ceramic pad and replace your front and rear rotors. Just don't buy any knock-off or no name rotors, those are made in China, not of greatest quality and will more than likely warp and crack.

[aarias298]

Ill be sure to replace the rotors as soon as i get the finances for them. Thanks for the help.

[CadenceScion]

Welcome!

[connman429]

When the mechanic says that your rotors need to be replaced, he is using a micrometer to measure the width of the pad contact surface. Even though the pads are what wear the most, the rotors will wear also. It is also standard practice to "turn" rotors when the pads are changed. This means they take a small cut off the rotor surface in order to give you a truly flat surface for the new pads. When the rotor width gets too thin, it becomes more likely that it will warp or crack. If you think the mechanic may be trying to pull the wool over your eyes, call your local Toyota service department. Ask them what the minimum rotor width is for the tC. Then, when you talk to the mechanic again, ask him to show you the measurement that he came up with.

As Cadence said, stay away from cheap parts, especially in the braking system. There are many different quality levels of steel. The metals that come out of China and India have many impurities. Just remember: if your motor fails, you wind up on the side of the road. If your brakes fail, you wind up in somebody's living room!

[j0nes]

Honestly I would just use that as an excuse to upgrade to something better, cross drilled/slotted are super nice but be very careful with the cheaper brands. I am saving up for the PWJDM Rotors, they seem to be real nice and like Cadence said stick with some ceramic pads or something, You will never go back if you do.

[navylife59]

All very good points. If you do not feel comfortable with what the mechanic stated about your rotors, you can visually inspect them for wear. From what you have said, it sounds like you have been the only one to change the brakes on you car. Is that a correct assumption? If so, then you should no if the rotors have been "turned" to true them. If they have been turned, it is very possible that they need to be replaced. Usually you can turn them twice without being too thin. That all depends on how out-of-round they were and the skill of the person turning them. The OEM ceramic pads don't wear down the rotors like semi-metallic pads do.

Schedule Maintenance Intervals only call for visual inspections and micrometer measurements on suspected rotors. There is no replacement interval as the rotors are expected to last for the "life" of your car based on the driving style of your average driver under normal driving conditions. They are, however, in that gray area of a "normal wear item". A quick visual inspection can reveal signs of excessive wear or if the rotors have been turned already. If you see a lip on the edge if the pad contact surfaces then it has either been turned already or excessively worn. Also, do you feel any pulsations when braking like when soft braking up to a stop sign

[aarias298]

Hey Navy, yea you assumed correctly. I have only changed my breaks myself, only twice. There isn't any deep gashes or anything on the rotors. But when you run your finger across the rotor it isn't super smooth (not sure if it's supposed to be super smooth, like a babies bottom) but it isn't rough either. The guy at Mavis actually said that i need to changed them because of the rotors having a lip on the edge. My rotors have never been cut. It could be very possible that the rotors got really worn down due to using semi-metalic pads. There is no pulsation when breaking, what i do feel is that the break pedal when pressed down sometimes feels soft, perhaps there is air in the break lines? Should i have my breaks bleed?

[navylife59]

As your brake pads/rotors wear down, that creates more volume in the calipers. The brake fluid has to fill in that extra space. The brake reservoir should have an ample amount of brake fluid to compensate. If it does not, then air can be introduced into the fluid as the reservoir is vented to atmosphere. This will cause spongy (soft brakes). Often times, the pedal feel will firm up some when new pads are install as it pushes the fluid back into the reservoir. It will, however, still need to be bled of any trapped or entrained air in the lines/calipers. New pads and a bleed job will give you back you firm pedal feel.

There are some other possibilities that can cause a soft pedal beyond what was explained in the previous paragraph. Leaking caliper seals, brake lines, and fittings can cause air to be constantly entrained into the fluid. If after bleeding your brakes you find that the pedal goes soft again a short time later, these may be the cause. The master brake cylinder can have a bad seal on the push rod allowing some of the fluid pressure to recirculate which will cause a drop in pedal firmness. This usually happens fairly quickly after a bleed, where as, the prior conditioned take a little longer as the norm. Did you know that on the manual tC's that the clutch master/slave cylinders share the fluid reservoir with the brakes? It is designed to deplete the fluid for the clutch first before the level becomes too low for proper brake action. However, it is possible that a low fluid condition caused by a clutch master/slave cylinder could set up a scenario where a brake leak or excessive pad/rotor wear can deplete the reservoir down to the point where air could be introduced while breaking in a tight corner or a hard stop with multiple brake actions.

In a braking system, the pads are considered "sacrificial". That is to say that they are supposed to wear at a much greater rate than the rotors. OEM's consider rotors to be wear items as well, thus, not covered under warranty for normal wear or increased were by the use of semi-metallic pads. It's a fact of life that rotors wear out and will have to be replaced at some point. As stated previously, mechanics use a micrometer gauge to check for rotor thickness and compare that the minimum thickness allowable listed in the maintenance manual. They also check for a condition called round-out with the use of a dial gauge. This is what causes the pedal to pulsate during braking. If beyond the manual stated limits for round-out and the rotor will maintain minimum thickness, the rotor can be turned (trued) on a brake lathe. DIY's have the ability to have their rotors turned at most local autopart nowadays.
A lip on the outer circumference of the rotor is not a sign of rejection. Only the minimum rotor thickness, severe round-out, and cracks are indicators of a rotor that will need to be replaced.

NOTE: Most rotors are designed with ample thickness to allow them to be turned about twice, under normal wear patterns, before needing to be replaced.

[aarias298]

Hello all, im re-visiting this thread. My brake pads are now close to being replaced. I also want to change out the rotors. I currently don't have sufficient funds to upgrade to EBC's Slotted/Dimppled rotors. So for now im going to go with the OEM brakes from the dealer and the OEM brake pads. So my question to you guys is if anyone has instructions to changing the rotors and breaks. I changed my break pads myself a few times and im planning on changing the rotors myself as well. Iv never done the rotors before so all the help would be great. I also will be bleeding the breaks and putting in new break fluid. Are there instructions on how to bleed the breaks also. I read around on other threads that using a synthetic fluid is best? I hope this isnt to much to ask of you guys.