Topic: Cleaning Master Cylinder

[Nortstudio]

I've watched the video on rebuilding the MC, but I have a quick question about cleaning it first.   I have a small bit of crud on the walls of the MC, and I'd like to get it out of there the best way.  Also, I have no way of knowing if that crud is also down in the holes.  I have let some Brake cleaner fluid sit in the MC overnight.

If the piston is not seized (like in the video), is still good to soak it a bit in hot water?

Is there a recommended way to clean the walls (fine sand paper, steel wool, scotch brite???).

Thanks

[Nortstudio]

Ok, I've soaked it in water, and sprayed a little more brake cleaner in there.  I guess I'm going to hit it with scotch Brits and hope that particles don't clog the small holes.  Unless anyone has a better suggestion.....

[HondanutRider]

I don't think that you'd want to risk "scratching" the cylinder walls by using an abrasive material like a fine sandpaper.  I'd soak it well like you are and then use 000 steel wool lightly if needed.  Also, using an air compressor to blow the holes would be advised.

[Nortstudio]

Thanks!  That's what I was looking for.  I had settled on scotch brite for that very reason.  I have some steal wool as well, but I would think that would potentially leave some pieces behind.  I'll take care of that with air and little more brake cleaner before the rebuild.

Appreciate the help.

[BobbyR]

Scott, the best solvent for old brake fluid is denatured alcohol. If it is crud and not corrosion the alcohol and small brush will bring it right back. You can rod out the passages with a copper strand from a lamp cord, speaker wire etc.

[Nortstudio]

Thanks Bobby.  I think it's crud, not corrosion. I hope

I'll make sure I clean out the holes as well.

[BobbyR]

Thanks Bobby.  I think it's crud, not corrosion. I hope

I'll make sure I clean out the holes as well.

My pleasure, we need you Scott to get GZ through NY not wadded up on the side of the road.

It is usually discolored crud and the Denatured eats it up quick. You want to stay away form abrasives is possible.

[Nortstudio]

I'll be good.  I'm at the point where I'm building all new projects for this bike off the bike with spare parts.  I actually have an aftermarket MC on there now (came with the bike) - but it's janky.

I have 2 spares.  The other one looks to be in better shape - but it came off a 750, so I figured I'd play it safe and do the 550 one.  They look aboutnthe same, but have different numbers inside.

I will be good for the rally.  Don't you worry....

[scottly]

My pleasure, we need you Scott to get GZ through NY not wadded up on the side of the road.

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