Brakes rusting

henry24

Just had my year old Mazda serviced at a main dealer and they have said my rear discs and pads are rusting away though being to gentle when braking and to brake harder.
I have been driving for nearly 40 years and never heard this before, I do about 25000 miles per year and do plan ahead to keep off them.

Anyone else heard of this?

Alter_ego

40 years ago rear brakes were normally drums -better protected from salt and water etc than discs.

vikingaero

That and the change in compound of brake pads. Rear brakes perform relatively little braking force and suffer more from degradation than wear.

henry24

So is it something that is only happening now? I had a Toyota for 3 years and 80000 miles before this and sold it with the same discs and pads and never got told anything about them rusting.

Shaka_Zulu

henry24 wrote: »

, I do about 25000 miles per year and do plan ahead to keep off them.

Anyone else heard of this?

There is your problem.

molerat

Shaka_Zulu wrote: »

There is your problem.

Start driving like a maniac and brake hard at the last second, your discs will be shiny again

wgl2014

Discs often get a thin film of rust if the car sits unused for a short while but that's worn away after a very short time driving.

If on a one year old car the rear discs and pads are rusting away I wouldn't be happy.

One thing that's worth considering is maybe the discs and pads are glazed not rusted and the garage have explained this poorly. Can sometimes happen if the brakes aren't ever used hard or if they are kept on gently for a sustained period like going down a long hill.

Op- have you had a look at the discs yourself?

EdGasketTheSecond

I've had a situation where the brake pad backing plate and pad material have partially seperated due to the rusting and bowing of the backing plate. Also had a brake lining completely come away from the shoe on a drum brake; again due to rust. The latter was awkward as it was like having the brake stuck on! Having said that, brakes should last many years before you get any problems like that. The brake shoe that seperated was the factory original and was about 15 years old but hardly any wear on it after 130K miles.

henry24

All they told me was that I wasn't braking hard enough to ware the rust off the rear discs so it's eating into them, just looking at them all I can see is what I would call a thin coat of old rust not new like when it's stood in the wet.

motorguy

henry24 wrote: »

So is it something that is only happening now? I had a Toyota for 3 years and 80000 miles before this and sold it with the same discs and pads and never got told anything about them rusting.

It depends on the braking pressures and bias of any particular car.

Most cars dont really need discs on the rear as most of the braking is performed by the front discs and pads.

Therefore the rears car end up with little exercise and as such the calipers will start to seize up. Once that happens the pads dont engage fully thus rust gets a grip, perpetuating the problem.

Robisere

Find a quiet bit of road occasionally. Drive slowly, with slight acceleration and slightly increased braking at the same time: one foot on each pedal. That will take off the rust. Are your brakes "binding" or sticking, is there even a slight grinding noise when you apply them? Open the driver's window to listen. If there is none of that, I wouldn't worry.

When I was in the trade, during a service I would check the discs and pads for wear. If they were OK but subject to the surface rust you describe, I would 'rough up' pads and discs with coarse emery paper, they soon bed back in with a little braking and are more effective. I have a feeling that the garage is trying it on with you, might be wrong but it sounds dodgy to me.