Caliper piston pitting, how bad is too bad?

[Royboy]

Getting ready to rebuild front and rear calipers. The old pistons have some pitting but maybe not enough to need replacement. Pic shows the worst of it, go again or replace?

roy

 

[retiredgentleman]

Roy, those pistons are junk now, time for some new ones. Of course you want new seals as well.

 

[ANLAF]

Roy, Retiredgentleman is right - they are goners. You can get a kit with cylinder, and seals. You can take no chances with brakes.

ANLAF

 

[5twins]

They sell stainless ones, and they really don't cost any more than the plain steel ones. I would get them.

 

[Royboy]

For the record, I know they are pretty bad. I bought a spare set of calipers from a member so I could have a go at polishing them. The pitted pistons came out of those calipers. Polishing turned out pretty well so now I'm thinking I might mount them on the 78SE but they'll need to be rebuilt.

roy

 

[ANLAF]

Roy, let's have some pics of the 78SE - my second bike is based on a 78. A thought just flashed into my head - you could still use the pitted cylinders as miniature plant pots, and mount them on the handlebars for some mobile gardening, or as miniature inkwells to catch-up with a few letters if the scenery doesn't capture your imagination.

ANLAF

 

[Royboy]

Actually, they are a perfect match for the bore of my spud gun. I think I'll put them in low earth orbit.

roy

 

[ANLAF]

Excellent...

ANLAF

 

[XSLeo]

About the right size for shot glasses.
Leo

 

[ANLAF]

That's right, Leo. Just need something for them to chase.

ANLAF

 

[lowliferat]

Mine was like those. I smeared a bead of job weld o smooth it out and I am running them. I know safety first but I only wanted to ride this for test run 2 1/2 years ago , I will change them eventually ?

 

[retiredgentleman]

Mine was like those. I smeared a bead of job weld o smooth it out and I am running them. I know safety first but I only wanted to ride this for test run 2 1/2 years ago , I will change them eventually ?

This just shows you have a poor safety attitude. I guess your rubber brake lines are 30+ years old as well. You've been lucky, and may get away with it, until the "accident" happens.

 

[lowliferat]

Hey your are correct sir , the lines are old and I have two front brake lines thrown together to make it long enough to fit the tall bars. I heard that stainless lines was the way to go? Maybe when I take her apart for a rebuild and quit riding so much? Thanks for the concern.

 

[XSLeo]

Even when new rubber lines expand under pressure much more than the braided stainless lines. This means that more of your effort goes to expanding the lines than operating the brakes.
The braided stainless more of your effort on the lever gets transferred to the caliper.
And they don't rot from the inside.
Leo

 

[Dusty]

I think those pistons are chromed over steel. If they are pitted,it's past the chrome. No amount of polishing will fix that. It will leak past the seal. Why do all that work just to do it a second time the right way??