E30 Zone

Doing some rust removal on my calipers as I want to paint them and they're tired looking but I might have messed up.
I pulled out one of the pistons from it's housing as the head (the bit that makes contact with the back of the break pad) was pretty caked in rust. I left the entire piston in solution overnight which removed said rust. However...
The outer shell of the piston was very polished before but is now dull and very slightly rough in parts. I'm prolly gonna put it back in after a rub but does anyone know from experience whether the piston actually needs to be spotless for it to glide in and out of the housing or if it can suffer a tiny bit of wear.

Thanks

I think you'll need to have it spotless and nice and shiney. Any spots of rust can cause wear on the piston seals as well as create a leak. It's prob less of a problem if the rusty area is near the pad as it might not fully go into the piston.

Be no harm either to get new seals and rubber etc for it.

Thanks for the reply Jozi.
After reading the following : http://www.venturerider.org/forum/archi ... 44970.html
I'm going to give the emry cloth and polish a go.
It won't take long to find out whether i've a problem or not.

dont got for emery cloth, you might make a low spot or make it too small, at most try some 1000 ish grit wet and dry, but be gentle, the edges of the piston are a bearing surface in effect and need to be smooth and quite precise.

your rusty bit will probably be outside of the seals anyway, hence why it rusted.

pics? its easier to advise if we can see what you can.