1 vs 2 remote reservoirs

[sethmark]

Does the cobra front and rear brake setup need a dual reservoir? I understand that with dual masters a line failure is isolated to the single master cylinder, but is there any reason to upgrade to one for each master? I won’t be racing this car.

[NAZ]

Dual reservoirs are not a race thing. The Feds mandated dual braking systems in JAN 1968 (FMVSS 105-68). Every car sold in the US since that time has been equipped with a dual braking system that includes two separate reservoirs. They typically look like one single reservoir but there is a dividing wall that effectively separates the front and rear M/Cs into two totally separate systems. Should a complete failure of one system occur the other has reserve braking fluid and will continuing working.
If you use one reservoir for both your M/Cs then should one fail and leak the only reserve brake fluid you have is what little is in the line from the tee to the working M/C. If the working system has no leaks then you will probably be OK. But if you have to pump the brakes for any reason you better hope that single line that holds your reserve fluid holds enough.

[sethmark]

Yep. I understand all of that which is why I ask... why ship a pair of reservoirs for a hydraulic clutch, car knowing full well 3 is more appropriate, unless they know something about the components I don’t.

[GoDadGo]

Yep. I understand all of that which is why I ask... why ship a pair of reservoirs for a hydraulic clutch, car knowing full well 3 is more appropriate, unless they know something about the components I don’t.

Most of the Ford Folks (Not Dark Side Guys) use a cable operated clutch.

I've got mine separated with a Tilton 3-Chamber reservoir.

https://www.summitracing.com/parts/til-72-576

[NAZ]

OK Seth, so you know all those details. Now you need to decide the minimum reserve fluid capacity you're comfortable with. If you want to run just one reservoir and split it between two M/Cs, you need to determine how long of a hose between the tee and the M/C meets your minimum reserve capacity. For instance, let's say you have a 3/4" Wilwood GS compact style M/C. That has a 1.25" stroke and will displace .55 sq in of fluid per stroke. If you want enough reserve capacity you can at least pump the brakes twice you need to have ~ 5" of 3/8" hose to support the second pump.

I've had a complete brake system failure on an old single M/C system. I can tell you that when it fails you will be pumping as fast as possible and as many times as you can before impact. I will always use separate reservoirs and even then, I go through the same drill to determine what my minimum reserve fluid capacity I'm comfortable with and order reservoirs with that minimum capacity.

[sethmark]

That’s the math I needed. Thanks. Lots of Japanese cars use a single Res system which I see lots of at work being turned into dirt track cars. But this isn’t a dirt car...it’s smaller, faster and lighter.

I’ve thrown away the old single pot masters in a number of 50s era projects I’ve built. This one from a 53 Chevy is my favorite. Clutch and brake hinge from the master. Yikes.

[sethmark]

Found this post to be interesting.....

[peterh226]

I'm planning to use these: OTB_6444.jpg
It may be overkill, but I'll feel better.

[NAZ]

Using the same ones Peter. They work good and look great.

[GoDadGo]

I'm planning to use these: OTB_6444.jpg
It may be overkill, but I'll feel better.

If it works and you like the look then go for it.
It's all about YOUR build.

[sethmark]

Here’s an interesting piece of information I learned today. A brake failure with a balance bar style pedal set up will yield virtually little to no brakes regardless of the reservoirs. When you step on the pedal with a balance bar set up and no pressure on one side, the drained side will go all the way forward leaving the short side to travel substantially less than normal.

It depends on a limit in articulation to stop travel enough to build some pressure.

[NAZ]

This is why the gap setting on the balance mechanism is important -- it limits the free travel. This setting is detailed in the instructions that come with the Wilwood pedal assembly. And also why it's important that your brake pedal is capable of providing full M/C piston travel.

I've seen both of these overlooked and that's an accident waiting to happen. Set the system up correctly and what you're describing won't happen.

[sethmark]

Without a doubt. These cars are rocket ships and getting the brakes just right is critical. We can’t just depend on the manual.

My balance bar gap was way over the .20-.25 recommendation and I wouldn’t have set it without reading the Wilwood info....