Cleaning up used rusted disks

Wire brush. Ideally a circular one mounted on an off-hand grinder, but it really depends on what you mean by 'surface rust' Mike.

Mike G expressed precisely :

That is what I had in mind.

The shine of the steel is still visible under the rust - so fairly light rust, I just don't want to fit them and use the pads to remove the rust.

then knock the worst off with sandpaper (emery/wet and dry is not recommended) and put them on. every time you leave the car out in the damp the disks rust a bit, so it won't really make too much difference in the end.

Fit the discs as they are, but put the old pads in. Use the car for a couple of days. Then when the discs are cleaned up, change the pads. Seemples.

Steve

Angle grinder and cup brush worked fine. I have got them cleaned down to the machining marks around the hub area, and the brake surfaces back to a shine. Just two tiny pit marks on one of the rears on the braking surface -so I'll call that a result then, apart from the angle grinder breaking down half way.

I got them given free, after the previous owner fitted up-rated disks. He says they have done 70k - I don't quite believe it. No grooving and no detectable wear.

New discs are pretty cheap for most cars - is it worth it?

asahartz brought next idea :

At around (I would guess) £150 for a set, versus half an hours effort, to me yes. I'm not by any means a greenie, but I also don't like to see things wasted, which are perfectly usable.

front disc and pad kit for rover 75 is about 65 quid

Why not emery wet and dry? Some thickish grade to remove the bad stuff as opposed to polishing the disks? (I probably would not have minded what paper I used but just trying to see what is in your mind).

Cheers C.

I read it somewhere years ago, I think the idea is that the sandpaper won't actually take away any disc, just the soft rust. The actual recommendation was to use garnet paper.

the paper I read on it appears to be this one, and it is all about curing brake judder caused by uneven deposition of brake pad on disc, quite a good read if you like that sort of thing:

I just paid £15 each for new (vented) discs for a Previa - not exactly a volume car.

Mrcheerful expressed precisely :

My (now) cleaned up and sparkling disks, still show the marks of the pads exactly as described in the above pdf.

No pitting, perfectly smooth and once clean the fronts measure 21.71mm and the rears 9.88mm.

Yup, perfect point on the emery paper. And the doc. you provided above pretty good, I can see in it one issue I have had and how I cleared it by chance.

Ta. Charles

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Harry Bloomfield saying something like:

JHC, are you mad?

Wire brushes are not designed to be spun at AG speeds.

Anybody looking at one of my discs wouldn't believe the mileage they'd done. Some of us aren't ham-footed.

they do make angle grinder wire brushes and they are very useful. Screwfix probaly have them, the clumps of bristles are twisted together and it is called a cup brush, they can wear out quite fast and you need full face protection and exposed skin protection, years ago I used one without face protection, when I went indoors I saw something on my eyelid, I touched it and found it was wire, it was embedded in the eyelid, when I pulled it out there was a flood of blood. I used better protection after that.

These were designed for use with an AG.

Nor I.

In my case it had gone through my jeans into my leg, didn't notice it till much later. eye protection's one of the things that was not considered optional when I worked at Lucas (as the union rep put it, "We're quite happy to fight for you, but we're quite happy for them to fire you for not wearing a pair of free glasses)

wrote:

Beware the Tiatan one that screwfix list are rated at >

Yes mine bounced of my thigh and then careered across the lawn, the Bosch replacement has been fine and quickly found the pinprick in a rusty fuel tank ;-)

AJH