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My original 1 1/16 stock master had 2 ports. My new master has one, it's a 7/8 Wilwood.

The stock proportioning valve has 6 ports. Pictured here:







How woud you go about routing my new single port Master?

My plan so far is to run it exactly like this with a simple adjustable prop. valve. The T before the adjustable prop. valve would go to the front calipers. Obviously one side to each side. The port exiting the adjustable prop. valve goes to the rear. Then tee it off with a brass T for the rear somewhere near the rear to reduce the amount of brake lines needed. This way would not use the stock prop. valve at all.








Any tips or ideas? Reasons why if I do it like this is wrong?

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Plans: Single Rotor turbo sub 1000lb machine!

Since it is a given that you are using a single master cylinder, there is nothing wrong with the design that you've shown. That's how my Caterham came (and performed fine for several decades). Only recently did I have to go to a dual master to be able to balance changes in caliper piston sizes.

Ron

Nice to know it has been done exactly the way I am thinking.

I was just worried that the front calipers see full pressure with nothing in the way. And only the rear gets adjusted...

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Plans: Single Rotor turbo sub 1000lb machine!

So you would have one master cylinder for front and rear brakes?

Seems like a really bad idea - stock master cylinders typically are designed so one failure won't take out both systems. Race style ones don't have any way to prevent this.

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-Andrew
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Yeah. That's what I was thinking. I drove for years with my MGA with a single master as all cars had prior to the mid 60's. But then the original Lotus probably had a single port master. But even knowing that, if I was building a car today, I wouldn't even think about a single port master. Each to their own.

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Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

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Race setups have a balance bar that's supposed to jam against its housing if one circuit fails, diverting pedal force to the remaining circuit.

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So like I said, "race" master cylinders have no way of preventing it.

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-Andrew
Build Log
Youtube

Sen2two, the pic is too small to read. I followed the link and tried to make it bigger, but it still was not legible.

600x800 is a good size to post directly.

I agree teeing to both master inputs would be the way to go.

I don't remember if it was said, but if this car must be inspected when completed, there is a strong possibility it will not pass with a single brake circuit. Just FYI. Any plans for an ebrake?

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LxWxHt
360LA 442E: 134.5x46x15
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Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Well, I do have a brand new factory 240sx master cylinder. It has 2 ports and it also the same bore size as the Wilwood.

I could use this instead of the Wilwood master.

Anyone here experienced with Nissan 240sx master cylinders?


Edit: After some research I found that the 240sx master cylinder I have is for an ABS car. Only difference it has vs. non-ABS is it has 2 ports, instead of 3. The non-ABS unit has 2 ports for the front and one for the rear. The ABS one has one port for the front, and one for the rear. No big deal, I'll split it off with a brass brake T for the front port. And one cool thing I found, the rear port is internally proportioned. So no need for a proportioning valve. Which makes routing everything much simpler.

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Plans: Single Rotor turbo sub 1000lb machine!

I had single master cylinders fail twice. Fortunately, both were in circumstances where only underwear was harmed.

The failure mode wasn't "gradually lower pedal." It was "thump to the floor" both times.

That would be my choice. As a plus, if I read the pictures correctly, you get a low-fluid sensor.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766