Tokico 3/4 Dual Master Brake Cylinder Differences

[iloveredmeat]

Hi all.

I have a couple of Dual Master Brake Cylinders.

Both are off of 67.5 1600s. Both are Tokico 3/4 inch.

See images below.

The one on the bottom is exactly like the original MBC my car had on it when I bought it, and I had a third that looked exactly like that.

The one on the top is the first I've seen like it.

This other MBC (top) is nearly identical, but has three differences I can see. First difference is that there is an extra pin/bolt to secure the front-most piston. The second difference is that the outside of the cups are smooth, not threaded like the others I've seen. The third is where the bleeder screws thread into the casting - the top one has 2.5 cm female threaded 'protrusions' in the casting, and the bottom has 2 cm 'protrusions'.

Everything else is identical, even the cups and the guts.

Does anyone know the difference between these two? Do later Roadsters (68+) have different MBCs?

Both of these have been rebuilt by Karps and I plan to keep one as a spare, but curious if anyone knows anything about the differences.

Thanks all.
Peter

[jrusso07]

Both my 70 SRLs have the one on top - with the stop screw on the side and in the front.

[iloveredmeat]

Both my 70 SRLs have the one on top - with the stop screw on the side and in the front.

Interesting... thanks Joe.

I figured it was an 'upgrade' to earlier designs, but wasn't sure if it was Roadster specific. Sounds like it is.

I wonder what year they introduced that design?

Thanks again,
Peter

[buenavides1]

Are these new or did you just polish them?

[iloveredmeat]

Are these new or did you just polish them?

I sent both of these and a third up to Karps Brakes to get assessed and all fixed up. I believe he does a chemical wash of some sort, they are prettier than when I sent them.

Here is the 'before' of the two shown. The bottom one is wet from a soak in Simple Green.



One master (not shown) was not worth repairing.

The top one was in very, very good condition, and he simply honed and installed a major rebuild kit that I bought from DatsunParts.

The bottom one was in good condition, too, but he thought it best to resleeve and rebuild.

So, they're both as good as new and ready for another 50 years!

[iloveredmeat]

Still learning...

So... I had always assumed that the brake master cylinder that was in my car was OEM. But now I don't think so.

As some of you know, I suffer from DRPA (Datsun Roadster Parts Addiction - as diagnosed by the Dynamic Doctor Duo @funkaholik and @ Gregs672000). And because of this DRPA, I somehow have 3 rebuilt tandem BMCs... at least one too many.

The first MBC is my original (shown below) and the other two are shown earlier in this thread.

As I was considering which one to sell, I looked at photos of my original (don't have it here with me) and realize it is significantly different than the other two, and so I'm pretty sure it's not OEM.

The most obvious difference that I can see from the photos is that the bleed screws are on the passenger side of the MBC and the casting opposite the bleed screws extends a bit.

Does anyone know what this Master Brake Cylinder would be from?

I've read that a 510 MBC will work, so is this a 510 MBC?

Thanks in advance.
Peter

[jrusso07]

I know the 510 master has the bleed screws on the inside/engine side. It also has metric fittings on the brake lines. So, I'm not sure how the hard lines are connected unless there is a metric to SAE connector in the MC output (can't see it in pic) or the output fittings where somehow changed to SAE. It could be a MC from some other car (not 510) with SAE threads. It would be great to know the car if that is true!

[iloveredmeat]

I know the 510 master has the bleed screws on the inside/engine side. It also has metric fittings on the brake lines. So, I'm not sure how the hard lines are connected unless there is a metric to SAE connector in the MC output (can't see it in pic) or the output fittings where somehow changed to SAE. It could be a MC from some other car (not 510) with SAE threads. It would be great to know the car if that is true!

Thanks Joe,

I'm not sure of the threads/output fittings.

And unfortunately it's going to be a while before I see my car again, but when I do I will do further investigation and post more images.

Unless he sells it, my brother has a 510 which I should be able to compare to as well.

Thanks again.
PM