Brake discs rusting

decbel

I don't do many miles in my Saxo so the discs do tend to rust. A few miles down the road and they are back to normal.

Before my last MOT on braking they were juddering. It still passed like that.

I got them changed anyway because it was annoying and pretty cheap.

System

Iceweasel wrote: »

I think that the OP's problem is that there is a wear ridge on the outer circumference of the disc that is preventing the new pad from contacting the disc surface near the ridge.

That is usually a combination of hardened muck and rust, the solution is to get a hammer and chip away at it usually by hitting the corner edge of the disc whilst slowly rotating it until it is all gone. It is very advisable to wear eye protection.

Iceweasel

Tarambor wrote: »

That is usually a combination of hardened muck and rust, the solution is to get a hammer and chip away at it usually by hitting the corner edge of the disc whilst slowly rotating it until it is all gone. It is very advisable to wear eye protection.

Then finish off by spinning the disc while holding a rough file at 45 degrees against the edge to remove any remaining little bits of crud/rust and to give as smooth an edge as possible.

But don't forget to check if the disc has reached it's minimum thickness.

sevenhills

Iceweasel wrote: »

Then finish off by spinning the disc while holding a rough file at 45 degrees against the edge to remove any remaining little bits of crud/rust and to give as smooth an edge as possible.

But don't forget to check if the disc has reached it's minimum thickness.

I may have made the problem worse by smoothing off the rust, but its still there, so the pads are not wearing away to grip the rest of the entire disc. I guess that might happen in a few more weeks.

sevenhills

Wookey wrote: »

I think posting that for someone to read who isn't aware of brake disc rust and who could well follow that advice is akin to giving a loaded gun to a 5 year old.

Under no circumstances ever put any kind of lubricant onto a cars brake discs.

Its good that you have to be 16 to get a driving license

Richard53

sevenhills wrote: »

I may have made the problem worse by smoothing off the rust, but its still there, so the pads are not wearing away to grip the rest of the entire disc. I guess that might happen in a few more weeks.

On most cars, the pad doesn't sweep the entire disc area. There is usually a small ring at the edge and another on the inside untouched by the pad. These, of course, get rusty without the pad to keep them shiny. It's absolutely normal and nothing to worry about, unless it starts to interfere with the operation of the pads. The key thing is the thickness of the disc on the shiny bit. It is quite tricky to measure this without a micrometer because of the scale built up around the edge, but it is easily done with the right measuring tools.

Ebe_Scrooge

sevenhills wrote: »

Its good that you have to be 16 to get a driving license

17 for a car

( OK, strictly speaking, 17 to start driving on public roads )

sevenhills

Ebe_Scrooge wrote: »

17 for a car

( OK, strictly speaking, 17 to start driving on public roads )

Its 16 to drive on public roads, if you are disabled

BeenThroughItAll

sevenhills wrote: »

Its 16 to drive on public roads, if you are disabled

Or if you want to ride a moped, or drive a tractor.

Ebe_Scrooge

sevenhills wrote: »

Its 16 to drive on public roads, if you are disabled

I never knew that - well, there's disability discrimination for you :-)