Newly Restored 509 Manual Brake Master Cylinder

[Kevin S.]

I recently bought a correct Julian dated 5455509 standard master cylinder, early 1969 cap, and bail wires from David Sokolowski and sent them out for rebuild. The restorer painted the entire master cylinder. My 6th edition book says the semi-circle area at the front of the casting is machined after painting and is natural finish, same for the boss where the brake lines thread into the MC.

I'm going to need to strip and correct the boss areas. Anyone have a couple of nice photos showing how the boss areas should look for NCRS scoring, or have an OEM MC that shows those machined areas.

Kevin
IMG_2908.jpg IMG_2903.jpg IMG_2904.jpg IMG_2906.jpg IMG_2905.jpg IMG_2907.jpg

[Jeffrey S.]

Kevin,
here are the best pictures I could get of the 2 areas that need to be unpainted. These are from my Oct 68 car. That is the original master cylinder that was rebuilt by White Post some 15 years ago. The unpainted areas where the lines are attached has some surface rust since it is bare metal. The "PG" doesn't show up as well as I would have liked but taht is the best I could do.
Jeff

[Kevin S.]

Hey Jeff,
Thank you for the photos.

Basically, minimal areas were left unpainted due to the machining process. Essentially, where the bleeder screws and brake lines were tapped and the "PG" or "DC" stamp area only, not the entire boss surfaces.

Very much appreciated. I think I've got it.

Kevin

[Jeffrey S.]

Not quite right yet. Only the area where the brake lines screw into the cylinder were machined. The bleeder area was not and should be painted. There was also a VERY tiny date code stamped into one of the brake line machined area. I can't remember whether it was in the front or back and it's very hard to see.
Jeff

[Kevin S.]

Hi Jeff,

Noted - the areas where the brake lines screw into the cylinder were machined.

The Julian date on my master cylinder is located just above the forward brake line. I attached a pretty clear picture of it. I will remove the black paint from the brake line areas per your note.

Kevin

[Patrick H.]

Note that the recessed area that I circled in red should also not have paint in it.

[Kevin S.]

Hello Patrick,
Thank you for that additional piece of information. I'll be sure to remove the paint from the inside of that recess area. Much appreciated.

Confirming - the immediate surface area around where the bleed screws were tapped and drilled are painted? I would have thought the machine process would have removed the paint from the surfaces while the threads were being drilled for the bleeder screws? Reason for asking is that I can see paint in one of Jeff's pictures and the other picture looks to me like some paint is missing behind the bleeder screw.


Kevin

[Patrick H.]

Confirming - the immediate surface area around where the bleed screws were tapped and drilled are painted?

No, it is all black

[Kevin S.]

Thank you, Patrick for confirming.

[Leif A.]

Here's a couple of pictures of the areas that are NOT painted...
image.png
image.png

[Kevin S.]

Hey Leif,
Thank you for the additional pictures. It certainly clears up what is painted and what is not.

Kevin

[Kevin S.]

Thanks everyone for the help and the photos.... turned out nice, including the inside of the recess area that Patrick noted.

Kevin

IMG_2930.jpg IMG_2926.jpg IMG_2932.jpg .

[Donald O.]

My original 509 MC with a casting date of April’67 is in need of a restoration. Who are the trusted shops to send it to?

I already have a Rock Auto generic on and bled so now I need to send mine out.

As a side note, there is stamping on the front machined pad. VIN 17842.

[Jeffrey S.]

I sent mine to White Post and several other friends have done the same and have had good results.
Jeff

[Don L.]

FWIW, +1 on White Post.

I’ve had them do 4 or 5 master cylinders for me and all have been terrific. These guys know their business.

Hope this helps.