Are my Calipers ruined???

[Guest]

~1982 GS1100GL

So i am rebuilding all my brakes and while taking my front ones apart i came across an unfortunate discovery... There seems to be some sort of emulsified something? all over the inside of the piston chamber and where the fluid seal goes. I've tried cleaning it with all kinds of NASTY chemicals but the stuff is REALLY stuck in there... also seems to be some uneven wearing on the inside of the chamber, (notice change of color about half way down the chamber)

Are my calipers toast? and if so does anyone have a good set they can sell or trade me?



Also, anyone know where i can find a NEW rear master cylinder? I've looked around a bit but can only find used ones here and there. and if they don't make new ones does anyone also have a good one they can sell or trade me?

Thanks again everyone, ride safe!

[Dogma]

Don't judge that master until you can inspect the bore.

The caliper's seal groove might clean up, but the bore does worry me. Try sanding it smooth and see if you can get a piston to get stuck in it. To clean the grooves, get a stainless wire wheel or three for your Dremel. Don't try the brass ones. The brass sticks to aluminum. It's hard to damage aluminum with the stainless wheel, but keep it moving anyway. I wouldn't blame you for looking for another caliper, but another will probably need cleaned up some too. Practice on this one.

[Bustedknuckles]

the word i would use to describe the master cylinder is "crunchy"

Moving the piston back and forth you can hear all kinds of scraping and the C-clip area is so corroded i cant even get the c-clip out, I'm just destroying it in the process... the brakes werent functioning when i bought the bike.

I would rather get one in better functioning condition and rebuild that one...

[tkent02]

I have a few of those rear MCs in good working order, and a few of those calipers too.

Send a PM if you are interested.

[Nessism]

You could try bead blasting that caliper but replacing it is best. That master is almost certainly corroded in the inside so I'd just trash it.

Before installing a used master on your bike, I strongly advise opening it up and looking for corrosion in the bore. No offence regarding Tom's offer, but I've seen lots of units with pitting. They may work okay in the short term, but long term durability is at risk if there is pitting on the bore.

[chuck hahn]

Throw it in the carb dip over night and scrub the well with a dremel and the little wire wheel. Nut pics work well for cleaning the seal grooves tight edges ( corners where the seal seats) .

The flat part of the seal groove can be cleaned with a small flat tip screw driver carefully scraping the crud away.

[Bustedknuckles]

I plan on going through everything 100%. I'm rebuilding the calipers and the Master Cylinder. and I plan on throwing some pretty paint on them too!

[greg78gs750]

looks like toast to me. do you want any question when it comes to brakes?

[Bustedknuckles]

I had just never come across that issue before so i wasnt sure if it was a death sentence or if it was salvagable. I think im going to get some in better shape and rebuild those.

[eil]

Not sure about the master cylinder, but I would bet that caliper will clean up just fine with some patience. It looks about how my 850 calipers looked when I tore them down. I cleaned them up and they work great today. All that crusty stuff is solidified brake fluid. I used a variety of implements to scrape out the crust and hit the bore very lightly with fine sandpaper. When the seal grooves are clean and the bore is smooth, you are good to go.

[Steve]

The inside of the caliper bore only touches brake fluid, so it does not matter what it looks like.

The only part of the caliper that is somewhat critical is the smoothness of the groove that the seal sits in.
Even that is not all that critical, as long as it does not distort the seal out-of-round.

.

[Bustedknuckles]

So after some delicate cleaning with a stainless steel Dremel wheel, then a nylon one, a pick, and some scotch brite.... Voila! calipers look MUCH better... Thanks to everyone that gave me cleaning suggestions, it gave me some hope that they could be salvaged and now, I think they are!

[chuck hahn]

Long as the groove the seal sits in isnt all pitted they should be fine.

[MK3Brent]

I'm glad you came to the same conclusion as some of us who have actually rebuilt and refinished these type of parts.

I too used some stripping acid, SS wire brush wheels, brass wire wheels, and elbow grease to clean these parts up.

Here are a couple before and after pictures of some Honda dual pot calipers I re-built.