Cleaning New Brake Discs

[paul.h]

I am replacing the front brake discs on our 2003 C3 1.4sx petrol, and the new ones from Citroen have been painted rather than using a grease for corrosion protection. To remove it from the braking area I have tried white spirit/turps substitute, brake cleaner and carburettor cleaner but none of these solvents work. Anyone come across this problem before, what do dealers use or is it left in place but that would contaminate the pads ? I am going to try and get some cellulose paint thinners to see if this will work.

[Johndouglas]

Is it maybe a peel-off plastic cover.

[paul.h]

If only it was a plastic film, no it is silver paint. Using emery paper will remove it but then the surface is left scratched. Our local Halfords has cellulose thinners in stock at £6.49 for 500 ml so I will give this a try.

[Johndouglas]

Maybe you're not supposed to remove it. Maybe they are similar to these:-

http://www.trwaftermarket.com/en/Products/Braking/Brake-Discs/

But if you're worried about the new pads, I suppose you could run with the old ones in for a few days.

[paul.h]

Thanks John, maybe you are right and the paint should be left on. It is a pity there were no instructions with the discs. Hopefully Iannez may add a comment later. I never got to Halfords and saved £3, a nearer accessory shop WMP had Carplan cellulose thinners (xylene) for £3.49 for 500 ml (Halfords is expensive for most things these days). It has not helped much but a wire brush is removing the paint off the pad area followed by wiping with white spirit. The paint on the hub contact area comes off with emery paper and since the max runout is 0.05mm leaving the paint on could have caused problems.

 

An internet search shows that Brembo also do some painted premium brake discs that do not need cleaning before fitting but their general instructions say to thoroughly clean the discs.

[iannez]

its just a zinc based heat proof paint that should be left on. its stop's any corrosion while the discs are in storage and also when there fitted as the paint is only removed where the pads make contact. less chance of a rusty lip and the alloy wheel reacting with the steel hub. only premium quality discs have it.

[paul.h]

Thanks Iannez. I have cleaned the paint off just on the pad contact areas (although it was not all the way across, just at the edges as overspray) and the hub contact area. Did I not need to do this and could I have just installed the discs straight from the box without any degreasing ? I will still put a bit of copper grease on the back of the alloys, they were difficult to remove when I first got the car.

[iannez]

yes mate you could have fit them straight on. if there painted theres no need to grease them as its just there to stop light corrosion during storage. if somehow they are greased aswell a degreaser should be used. carb cleaner, thinners etc. discs should be scuffed up during a brake service with emery cloth/sandpaper so using these on a new disk face would not have been a problem. no harm done anyway paul.

[paul.h]

Thanks Iannez. I fit the new front discs and pads today, straight forward enough and no problems. Old discs were down to 11.2mm from 13 and pads were down to 6mm so they were due for doing, better now than in winter. Car on 36k miles, 7 years old but mostly short trips.

When pushing in the piston I opened the bleed nipple on each caliper to let out the excess brake fluid, rather than pushing it back into the hydraulics, since jojo42 has reported an abs problem possibly through not doing this.

I did notice the rubber bushes on the lower suspension arms are starting to perish so this may account for a clonking noise and could be my next job. Eurocarparts do a complete arm with bushes and ball joint for about £40 so I will have to check Citroens price. I usually prefer the dealer parts since they fit better and last longer.