Surface rust on new discs

jonislost · 13 Apr 2011 at 11:49

Just had a full set of new discs and pads added to my Mondeo and they looked great to begin with, but yesterday I let some poles loose on it in the local tesco car park car wash and since then I've got some horrible orange/brown surface rust on the discs which doesn't seem to be coming off. Normally when I wash it comes off after a quick drive... Any ideas on how to get rid? Any product recomendation?

acemastr · 13 Apr 2011 at 11:54

You'll find this happens with every disc (apart from ceramic) and will usually happen within about an hour of washing the car/rain, the second you start moving the pads will rub off the rust and you're back to shiny.

Give it a good hard brake and it'll scrub them.

Firestar_3x · 13 Apr 2011 at 11:55

A light spray of WD40 onto the discs will stop the rust forming *, **.

* May reduce braking preformance.

** Don't do this.

mjt · 13 Apr 2011 at 11:56

Firestar_3x said:
A light spray of WD40 onto the discs will stop the rust forming

I hear Hammerite works just as well.

Philz0r · 13 Apr 2011 at 11:57

hmmm, ive recently replaced all my pads/shoes/disks/brake lines and brake oil. the brakes feel great but they are constantly squeeling. any advice. ps they've been on about 4 weeks now. (on a vectra)

jonislost · 13 Apr 2011 at 11:58

acemastr said:
You'll find this happens with every disc (apart from ceramic) and will usually happen within about an hour of washing the car/rain, the second you start moving the pads will rub off the rust and you're back to shiny.

Give it a good hard brake and it'll scrub them.

Yeah that's what normally works... I've done 150miles since the was now and still murky and horrible

Mucky_Pup · 13 Apr 2011 at 12:02

Philz0r said:
hmmm, ive recently replaced all my pads/shoes/disks/brake lines and brake oil. the brakes feel great but they are constantly squeeling. any advice. ps they've been on about 4 weeks now. (on a vectra)

Try some copperslip on the back surface of the pads.

Relentless81 · 13 Apr 2011 at 12:02

You dont need to spray anything on the discs it is normal

JamesM · 13 Apr 2011 at 12:26

I tend to paint the rusty parts of the disk that don't come into contact with the pad either black or silver. Makes things look a nice nicer imo!

bledd · 13 Apr 2011 at 12:31

jonislost said:
Yeah that's what normally works... I've done 150miles since the was now and still murky and horrible

Brake sharply, should wipe it all away

Matt82 · 13 Apr 2011 at 12:47

JamesM said:
I tend to paint the rusty parts of the disk that don't come into contact with the pad either black or silver. Makes things look a nice nicer imo!

yup, quick spray before fitting. takes a lot longer for the corrosion to set in that way

Gaijin · 13 Apr 2011 at 14:53

A test emergency stop is in order.

ubersonic · 13 Apr 2011 at 15:10

If you apply a light coat of PVA glue to the discs it will solve the problem

Firestar_3x · 13 Apr 2011 at 15:12

mjt said:
I hear Hammerite works just as well.

Top tip, burger fat works well too.

On a more serious note, my OEM rear VW discs are yet to rust up, I’ve got no idea what metal composition they've used but it’s very rust resistant.

Scougar · 13 Apr 2011 at 15:15

Can you get a picture, because unless they have been pitted/scratched there is no way they should still have any contamination on them (at least on the mating surfaces!)

Dup · 13 Apr 2011 at 16:52

A lot are zinc coated now I think. Thin enough to rub off on the braking area but the rest of the disc stays nice.

My cars been stood for nearly 8 months now. They're gonna fail the MOT aren't they? Weren't that old too

mattyfez · 13 Apr 2011 at 20:49

Philz0r said:
hmmm, ive recently replaced all my pads/shoes/disks/brake lines and brake oil. the brakes feel great but they are constantly squeeling. any advice. ps they've been on about 4 weeks now. (on a vectra)

You needs to bed them in.

Warm them up from say half hour town driving, then do 3 or 4 "emergency stops" from 60mph down to 10 mph, on a quiet road, and don't have your foot on the brake when stationary, allow the brakes to cool.

Job done.

Batf1nk · 13 Apr 2011 at 20:55

Dup said:
A lot are zinc coated now I think. Thin enough to rub off on the braking area but the rest of the disc stays nice.

My cars been stood for nearly 8 months now. They're gonna fail the MOT aren't they? Weren't that old too

Don't see why it'd fail it's MOT. I had an old s13 that was stood for years and passed it's MOT fine when I finally got it going. Didn't touch the brakes at all in that time.

Just took the 'long route' to the MOT station (about 15 mins) and the disks were fine.

mattyfez · 13 Apr 2011 at 21:06

Also, disks will get surface rust if stood for a week or so, they can be re bedded if not too rusty

http://www.zeckhausen.com/bedding_in_brakes.htm

Lopéz · 13 Apr 2011 at 21:09

To fail an MOT on rusty discs they have to be in a ridiculously poor state. My tester went on a refresher recently and rusty discs was one topic that was covered in depth. He was told if he'd consider putting it on the rollers then it was good enough to pass and advise.