'40 Lockheed brake system

[russcc]

Converting the '40 system to DOT 5. I have done this before on the roadster, but was wondering what the aprox. brake fluid capacity is for the '40. I have rebuilt the wheel cylinders, and MC, and cleaned out all the brake lines, so it's empty. By the way good tip from a forum member to blow out the brake lines with brake clean. It Did a great job sterilizing them. Thank you Fordarners.

[19Fordy]

Don't know for sure but I would buy 2 qts. That way you always have some if needed.
I have DOT 5 in my 40 and used Speed Bleeders.

[philipswanson]

I would convert to Bendix (Lincoln style) brakes
in the front. Much improved stopping distance.

[flathead 53]

I agree go to the bend brakes for the front , you can use front brakes off a 1953 to 56 f-100 also, they are a big improvement.

[Juergen]

It's not the capacity of the system that is of concern but how much you waste bleeding the brakes. It is harder to get all the bubbles out of DOT 5. I got the fastest results using a vacuum at the bleed port while pushing at the master cylinder. Others say the vacuum doesn't help. I went through one can before trying the push/pull approach.

[rotorwrench]

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I don't know for any certainty what a 1940 Ford brake system fluid capacity is but it shouldn't take more than a regular pint bottle even with bleeding loss. A guess would be around 6 to 8 fluid ounces. This would be for a completely empty system needing to be filled to capacity.

Dot 5 tends to deteriorate as soon as you pull the seal off the bottle. I like to get fresh stuff for a car system that is being refreshed back to serviceable condition. For top up service, it's not as critical. They say DOT 5 doesn't hold moisture but it seems to me that is does but less so than DOT 3. None of them last forever.

[russcc]

Thank you all for your valued advice. I have early Lincoln Bendix brakes which I will eventually install on the front of the '40 but not right now.

A perspective on original '40 Lockheed brakes from an old time expert Ray Helgers in RI, is that properly installed and maintained stock '40 brakes will "Put you through the windshield"

[Tim Ayers]

Originally Posted by russcc

Thank you all for your valued advice. I have early Lincoln Bendix brakes which I will eventually install on the front of the '40 but not right now.

A perspective on original '40 Lockheed brakes from an old time expert Ray Helgers in RI, is that properly installed and maintained stock '40 brakes will "Put you through the windshield"

Yes, they will. Properly adjusted mechanical brakes will too.

[Anteek29]

My view about mechanical vs. hydraulic brakes...if you can lock the wheels the difference is moot.

[19Fordy]

It would be interesting to perform a test between Bendix and Lockheed systems to
see which stops the car in the shortest distance and which requires less pedal pressure to get the brakes to lock up.

[rotorwrench]

It depends on the weight of the vehicle and the tire patch dimensions on the ground. I'd say the mechanicals might take more leg pressure than the hydraulics but both will stop the car. When the adrenaline kicks in, folks likely wouldn't be able to tell the difference.