yourmom23

iTrader: (4)

Ok so i pulled my brakes off and popped out my cylenders. THey have some rust/pitting, on the sides of the pistons. I was just wondering how much is normal? It is pretty minimal but i just dont know if it will be a sealing problem or not.

alexdimen

iTrader: (13)

I've seen some decent pitting that honed out on this antique Merc 190SL i did the brakes on a couple years ago.

You have to hone it anyways, so see if it hones smooth, if not get new parts.

...you were gonna hone the cylinders, right?

yourmom23

iTrader: (4)

NO i was going to grind off the rust with a cutting wheel.... ha I really think that the pitting is so minimal that it wont matter. I didnt think you could take down the outside diamiter..

alexdimen

iTrader: (13)

hehe, well younever know with people on the internet. I know i didn't know to do it years ago...

You mean the cylinder bore diameter? Maybe check the FSM for brake rebuild specs, but i doubt you could change it significantly by honing it out unless you took your time and tried to.

yourmom23

iTrader: (4)

Well the rust is on the piston the outside, dont know maybe i confused you. but i should take a closer look at the actual bore aswell

DaveW

The caliper bore is not as important, except for the seal grooves. The piston slides on and seals to the seals, so the finish there IS important. However, as long as the pitting on the pistons is very small, it will not affect performance, since the seals will bridge the pits and still work as intended.