Continuing on from rebuilding all the original suspension components, brakes are next in line.

Fortunately my May 1970 240Z came with the early brake rotors. I have derusted them, machined to tolerances and painted them to original spec. The hubs are cleaned and painted and I have NOS OEM bearings for them. A set of original Nissan brake pads have also been sourced. The brake calipers are the correct date coded set for 1970. I have degreased them in the ultrasonic, cleaned off all the corrosion using a acid solution. A light sandblasting and high temp satin clear finish give them the factory new look. A NOS OEM Nissan caliper seal kit is used to finish the build. All bolts and fittings are re-zinc plated. My goal is to use all original/OEM parts in my restoration.

Edited 22 hours ago22 hr by SpeedRoo

An original early brake master cylinder was also sourced for the restoration. The ultrasonic cleaned it up nicely and I've disassembled it and replaced all the seals with original Nissan/Tokico parts. I just need to bleach the plastic reservoirs so they are nice and white.

It should look like this once complete.

Edited 22 hours ago22 hr by SpeedRoo

Roo, Nice work on the brake stuff. I have a couple comments / questions about the master cylinder:

First, where did you find the rubber seals you used to rebuild the master?

Second, the pistons originally had a black oxide coating presumably for friction reduction and/or corrosion protection. It looks like you hit the pistons with a wire wheel and burnished that coating off? Any thoughts about having them recoated?

And last, a little pedantic, but I'm thinking that is not quite the correct master cylinder for a 5/70 car. I'm no expert on the early cars, but I think you should have the one with the ground and stamped "F" and "R", not the cast-in markings. The correct one I believe would look like this:

There was some discussion about such matters here >> https://www.classiczcars.com/forums/topic/65579-brake-master-cylinder-46010-e4602-up-to-91971/?&page=3

@Captain Obvious I've been buying them up from Ebay, they pop up every now and then. Last kit was in Feb this year, I got the pistons/seals/springs/washers for $85!

Yes the piston did have the black coating, it was already coming off when I stripped the cylinder down. I hit them with the brass wire wheel to clean them up. I'm not sure the original coating from 50 years ago is still available so I'll keep them as it is. Hopefully nobody faults me for this.

Nothing wrong with pedantic, you guys have been doing this longer than me and are more knowledgeable. Thanks for pointing it out. I have a rebuilt cylinder with the early engraving, I'll make sure I use that now I know it's the correct one. I have two of the cast type so I'll keep those for the later August 1970 and October 1970 240Z I have. Anyone know the exact changeover date?

I'm using the Green May 1970 240Z that went for $310k on BAT as my reference along with @Zspert for his intimate knowledge with the cars.

Again appreciate you correcting me and guiding me to the correct parts for my restoration.

Wow. I wish I could nap a set of pistons/seals/springs/washers for $85. If you see another one of those, please send me a quick note to let me know?

Nobody will see the pistons after they are installed, so it's not like you're going to be judged on whether that coating exists or not. And I understand about polishing it off... The decision which is better...Keep some of the original failed coating, or just remove it all. Totally understand. If you do decide to look into it, there is probably nothing very special about that coating, It's a black oxide coating on steel. It's a controlled rusting kind of coating. Similar to "gun blue". Any coating shop should be able to reproduce it, but cost prohibitive for a single piece.

As for the changeover point between the stamped lettering and the cast-in lettering? In that other thread it appears that point is between 7/70 and 12/70 when they changed the markings from stamped-in to cast-in.

I got the chance to mess with a 9/70 car and it had the cast in lettering. So with a sample size of one, I could narrow the date window down to between 7/70 and 9/70.

However:
1) It's a sample size of one.
2) I don't know if it was the original brake master on the 9/70 car, and...
3) The 9/70 car was an automatic, and some of the stuff on the autos is different than the manuals from the same month (valve cover for example).

All that said, I think your MAY car should have the stamped lettering.

Edited 3 hours ago3 hr by Captain Obvious
typo

@Captain Obvious I'm always on the lookout for NOS OEM parts, sometimes they have the right part number but are not in Nissan boxes...you just have to know where to look. I have a spreadsheet with all the period correct cross reference numbers and keep a look out for those on a regular basis. It seems the Nissan part suppliers of the day back in the early 1970s had no qualms about selling the same part to Lazorlite/WorldParts/BeckArnley.

I wont try and reproduce the coating, too many other parts to restore at the moment but will keep it in mind for the future.

I will use the master cylinders with the cast in letters on my 8/70 and 10/70 240Z, the engraved one will go on the 5/70 for period correctness.

The fun anomaly I have discovered in the wire clamps. Some people say they should be all clear zinc, other say gold zinc...what's correct. Again referring back to the Green BAT 5/70 240Z, it has gold zinc wire with clear zinc screws...go figure that one out as it's totally original. However the large ones on the radiator hose are clear zinc.

Edited 2 hours ago2 hr by SpeedRoo