Honda CB750 Sandcast

Refurbishing Master Culinder and other parts

42barab

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I'm very new to refurbishing anything, so I want to be cautious.  Just took possession of a Master Cylinder and a ground (earth) cable.  See pics.  Wondering the most efficient means to clean up both.  I want to rebuild the MC so first step is getting the innards to loosen so I can remove them.  Can the complete MC be submersed in a rust remover (e.g. Metal Rescue)?  Or is it better to soak the insides with a penetrant?  The ground cable looks to be 100% braided wire, so I don't see any issues with soaking it, as long as I dry it out before use.  As for the brake lever, can the end of the handle be bent back into its proper configuration?  If so, would a propane torch work?

And after disassembly, I want to send the MC out to get a Chromic Black Anodized finish.  What would be the best resource?

Please see pics below, and ask for more if needed.  Thanks



Sam

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My approach to restoring a master cylinder:

1. Remove the internal components. This can be tough with old rusty master cylinder components. I have a special pair of pliers that I shaped to be able to grab the circlip. Once that circlip is out, the rest of the internal components will come out easily.

2. Send the master cylinder, cap and bar clamp to have the old anodizing removed. This will likely be done by the same place that will eventually anodize the parts. I usually have them mask off the internal parts of the master cylinder.

3. Polish the parts as best you can.

4. Have the parts type 1 (chromic) anodized in black. Again, I usually have them mask off the internal parts of the master cylinder.

Ask your local anodizer if they can do type 1 anodizing. I have a local place in East Palo Alto that I and few others on the forum have used:

Sanford Metal Processing Company

(650) 327-5172‬

990 OBrien Dr
Menlo Park CA 94025

Good luck!
Ujeni Motors
Sandcast #410
Sandcast #538 Watch the restoration!
Sandcast #6592 All original daily driver.
Diecast #16608


42barab

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Thanks for the very helpful response.  I got the innards out with minimal effort.  Then honed the cylinder (about 15 seconds) with 1/2" multi stone 320 grit via slow speed drill.  Then 800 grit and finished with 1000 grit wet/dry sandpaper. 

I've never done anything like this before, so I have some questions.  How clean should the MC exterior be before sending it?  Presently it's soaking in a Metal Rescue bath.  Since Sanford has done yours and probably others, how much information and direction do I need to give them?  Is it sufficient just to tell them to black chromic anodize the exterior as Honda did it in the 70's, or will they need photos?  The end of the cylinder that rests under the banjo boot seems to have the correct finish, although a bit faded.  See pictures.  Thanks

John


Sam

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Sorry for the delay in my response.

You will need to have the anodizing removed via an acid bath at your local anodizer. Though it appears that the original anodizing is only under the rubber cover (where it appears darker), the reality is most likely that the anodizing has faded on the exposed parts. That means it still needs to be removed before you can start polishing.

The sanford folks are pros. Give them a call and tell them that I sent you (Sam Roberts from Santa Cruz). Tell them you want chromic anodizing in black and tell them what areas you want masked off. Again, this assumes that the anodizing has already been removed and that you have polished the surfaces. I am actually headed to their shop today or tomorrow to pick up a bunch of work!

Ujeni Motors
Sandcast #410
Sandcast #538 Watch the restoration!
Sandcast #6592 All original daily driver.
Diecast #16608


42barab

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I found a local shop that can strip and polish the MC, so I'm taking it to them this week ( I don't have a polishing wheel.....yet.)  I noticed that the banjo bolt end has a sleeve, as compared to another MC I have that does not have a sleeve.  And most of the ones I've seen don't have one either.  Was the sleeve a retrofit fix for stripped threads or did Honda produce some with a sleeve?  See pic.  Thanks

John


4pots1969

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I think it's a master cylinder that has undergone a repair... ???


vnz00

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I would check if that is a steel sleeve before sending it away - if so, it wont react well to the anodizing process.


4pots1969

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I would check if that is a steel sleeve before sending it away - if so, it wont react well to the anodizing process.

Yes, but at the same time, once the bolt is screwed with the seal plus the rubber protection, we will not see anything ... The real concern for me is the risk of leakage if it has not been done properly...