Noise from Brakes

Does it sound like seal bark?

My Brakes are Barking at Me | Page 4 | PriusChat

 

Mine is in the shop and getting the brake actuator replaced. Hopefully it isn't that in yours.

 

Why are you pushing the brake pedal all the way to the floor? Under normal driving a Prius owner should rarely ever use his conventional hydarulic brakes. Regen braking saves your brake pads and helps your MPGs. The downside is a Prius' rotors turn to rust very quickly, a trick is once a month get up to speed and when safe to do so slam on the brakes, this overrides the regen braking and clamps down on the regular brakes, knocking any rust off the rotors and drums that had formed since the last time you had performed a hard stop.

you have described the noises but not how anything feels. Do the brakes feel strong when you are stopping? Does it feel like there is any 'drag' while you are driving, are your mpgs down? if so you could have a caliper malfunction (not releasing the pads from the rotor). This is why when I do a brake job, even if the rear brakes are fine I still spray them down with brake cleaner to get all the brake dust out of the drum. Sometimes problems and noises at the rear sound like they are coming from the front, its hard to be certain when you are inside the car as the soundwaves are bouncing all over the place. It is also very important to lube the caliper slides with high temperature brake lube. Hydraulic fluid is very strong, so is your foot, you're almost always certainly going to be able to stop, but when its time to go again you want the brakes to release and that's where the caliper lube comes into play.

As I stated a Prius rarely uses the brakes so your steel rotors will rust from the inside out. Once that rust creeps over the top and back onto the actual surface that mates up with the pad, you're going to get noises as the pads are designed to quitly stop a smooth steel rotor, not a rusted one. This is a safety issue, replace the rotors and lube the slides as your occasionally noise will get worse and worse as the rotors get rustier and rustier. Rotors must be clean and oil-free in order to work properly, therefor you cannot coat a rotor in any sort of oil or rust-inhibitor, so a Prius owner should just buy cheap POS rotors from advance auto parts and consider them to have a short life.

There was a time when rotors lasted well over 100,000 miles and pads had to be changed every 15,000 miles. times have changed, rotors are getting thinner to save weight and improve fuel economy, the money you save on fuel by using a lighter rotor will far exceed the extra cost of a few sets of extra rotors. the brake pads on a Prius can easily last 100,000 miles, some people report using 25% of the pad in 80,000 miles so do the math. But that doesn't mean you can just throw on a new rotor as the pads have been grooved and mated to the old rotor, you should put 2 or 3 different sheets of sandpaper on a smooth surface (glass is best) and sand the old brake pads down before reusing them.

 

Your brake pedal is connected to a rod that goes into the brake master cylinder on the other side of the firewall, your foot provides the necessary mechanical force to push the rod in, inside there are springs that will push it back out, you don't want to constantly be compressing those springs as they may not want to come back out all the way, which may lead to future problems.

I have a couple of '74 Sonett's and my biggest fear is always brake master or clutch master cylinder failure. Some people even put a block of wood under the carpets just so they can't accidentally overextend rods. my $.02, good luck breaking the habit.