Topic: Any fixing brake piston

[jays75]

Sup,
I have successfully broken down my bike and now it's time to replace stuff.  The stuff in question is my brake piston. I have a '75 550 and when I took apart my front brake, which was quite easy using the grease gun method, I noticed the piston had some pits in it right where it sits on the seal.  Question is do I try and clean that up or do I replace the whole thing?  If I replace it then where can I get a good piston from? 
I could buy them all day off ebay and what-not but I figure those pistons would be pitted just like mine.  I dunno.  Maybe I need more faith in people.  Any help in this matter is a huge help.  Right now I'm at a stand still until I get this front brake back together.

[knowsnothing]

Hey Jay,

You will most likely need to replace that piston.  Luckily a member here (Kevin400F) makes phenolic replacements, which are lighter and just as good if not better than OEM.  I am pretty sure he makes one to fit your bike.  Go here for all the info >  http://forums.sohc4.net/index.php?topic=66881.msg736356#msg736356

[HondanutRider]

Depends on how bad the pitting is.  (Maybe a picture would help...)  If its not too bad, they usually can be cleaned and polished, and with new pads and maybe a new seal, the pits won't cause a problem.  If you use new pads, then the seal will be positioned in a new spot, hopefully avoiding the pits.

Another route, probably better, is to get a new piston.  This is possible for some models (but not for my 81 DOHC CB750-K - as I found).  In fact, one of the members here builds phenolic pistons that don't rust or pit and the reference above is to him.

[bryanj]

Is your life worth more than the cost of a proper brake rebuild?

[Duke McDukiedook]

Phenolic, no need to look elsewhere.

[bollingball]

DO NOT take a chance on brake parts !!! Being able to stop is way more important than being able to go fast.

[faux fiddy]

Carcass bikes all seem to be missing the  handlebar controls, master cylinder first. AWhat does that tell you?

i'm looking for a 350f master cylinder. I think the 550 is the same.I will check back on this thread..

[the architect]

Another option, other than phenolic, is stainless steel.  I picked up a s.s. piston when I rebuilt my K5's caliper last year.  Should nver corrode or pit again.  And it's metal.  I like metal. 

[Duke McDukiedook]

Stainless steel corrodes, ask the people that maintain the gateway arch.

[Kevin400F]

I understand there are skeptics about the phenolics.   They work, I have one in my track bike (see pic below)  I'm not worried in the least bit about function, but please make a choice that you are most comfortable with.

[jays75]

I think I'll go with the phenolic.  Sounds simple enough and simple is good.  Thanks again for all your replys to the topic.
J.