Topic: San Jose Disc Brake Distribution block and prop valve finish

[69supercj]

I'm in the process of getting my SCJ back on the road after a 15 year hiatus and I'm working on the brakes. What is the correct finish for the distribution block and the prop valve? Polished brass, dull brass, satin brass, ect? Also the same for the mounting bracket for the block and the prop valve hoop bracket. Thanks!

[ruppstang]

The finish on the brass would be a satin brass. The distribution block bracket is zinc dichromate. The proportion valve clamp is phosphate and oil. 

[Bob Gaines]

To add - the satin brass finish is the result of chemically polishing originally however if mechanically polished (by hand etc.)to a not too highly shiny finish it will dull down to the satin finish fairly quickly because of exposure to the oxygen in the atmosphere over time (weeks ,months). One way is to do one in advance and put it on the shelf to dull down on its own. Another way is after cleaning expose the brass to a acid product like muriatic acid,vinegar etc. You need to experiment on a test part first to see what concentration and time exposed  (typically seconds ) to get the desired finish. Once it gets to the acceptable finish you need to stop the oxidation process by some means (clear coat, oil etc.) so that it does not dull down past the appropriate range of finish for that assemblyine look. Of course the part needs to be completely disassembled from the steel bracket for proper restoration of all parts.

[preaction]

Im at the point of removing the steel mounting bracket for a distribution block restoration is grinding down the brass that seems to have been swaged to the mounting bracket and trying to leave enough to reswage  or peen over the brass to to remount the steel bracket after zinc dichromate plating ?

[J_Speegle]

Im at the point of removing the steel mounting bracket for a distribution block restoration is grinding down the brass that seems to have been swaged to the mounting bracket and trying to leave enough to reswage  or peen over the brass to to remount the steel bracket after zinc dichromate plating ?

Would be careful about removing/grinding down since you want material left attached to be able to reattach.

This is where you might want to find another junk one (other years or model cars) and try out the process on it before you try it with your restored one.  Hope it goes well with what ever path you take

[Bob Gaines]

I have never ground material away to get the bracket off. You have to carefully push the brass back from the sides so that you can release the bracket . Many different kinds of tools can be used to accomplish this. Reverse the process when re attaching. Hopefully not too much brass material will break off.

[preaction]

Thanks for the insights after finding a picture of a removed bracket and being able to see the rectangle shape of the brackets slot helps a great deal.

[Anghelrestorations]

Sharing a photo of what I have done in the past that shows a good before and after and what I think is the correct finishes. 

P7100193 by Marcus Anghel, on Flickr

[Daven]

Looks awesome Marcus!  I have to dichromate my bracket yet.  I was surprised at how easy it was to rebuild it!  A fantastic you tube video out there on the exact distribution block and proportional valve rebuild.

Daven