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Hey all,
I was coming back from Dairy Queen and a few blocks from the garage, my brakes started feeling soft. I limped it into the garage and after removing the cap to check the brake fluid, it was really low!
I had to use an oil wrench to get it off, but it looks like the top of it says "OR3 Brake Fluid"

Best I can tell, this is all original to the '65. It looks like the lines are made of brass, and the 1 unit controls all 4 brakes. (they are manual drum brakes)

For my 1st step, I'd like to add brake fluid to see if there is a visible leak, or if it's been a slow leak over the years. Based on the cap saying "OR3 Brake Fluid", what is the proper fluid to add? (I don't know what the previous owner put in there)

Thanks!
 
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If you want to get your braking system up to date, remove your single pot master cylinder. That setup is dangerous. In '67 it went to a split system which is a fairly easy upgrade that will improve the safety factor a lot.
 

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DOT-3 DOT-4 synthetic brake fluid from a major brand. Every 3 years have the fluid replaced.

The synthetic premium fluid has better protection from moisture, that is more additives.

Especially in a car that sits in places with humidity and large temp changes during the day. That allows for the system to bring in more moisture.

From experience a car that is not driven much should have the fluid changed about every 3 years. The fluid then gets loaded with too much moisture and you can start having wheel cylinders siezing up. Then you get less the 100% brakes and they fluid can get on the shoes. The new shoes do not like this much and seem to melt, this was a 5 year old set of Wagner shoes.

You should get the kit to convert the master cylinder to the dual system for safety!! Pretty easy to do.

Be warned, if you have to replace the wheel cylinders take apart the new ones. The made in China (all that seems to be out there) rear 6 cylinder ones had the bleeder in the wrong place. The hole was not at the top of the cylinder so you would not be able to properly bleed them.

Shoes are also not even close to a standard size. This is bad as they will not wear in fast leaving you with poor braking. Take the shoes to a brake shop that can arch them to match the drums. This makes a HUGE difference in the brake action with the new brakes.
 
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And to be different, I use DOT 5 in all my classic vehicles. But what's more important is getting rid of that stock type MC :)
 

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DOT 3/4 or 5.1.

About the single bowl M/C..... I've been in 2 cars where the M/C had failed, in the days prior to 1966. Not a good feeling. Hand brake slowed us down. In both cases the failure was immediate. Last brake application was normal, next brake application was like stepping on a rotten tomato. Sure, there are thousands of cars driving around on single-bowl M/C's... There are millions of cars driving around on bald tires, too....

Pull the original, flush it with brake solvent or denatured alcohol and throw it in a ZipLoc with a desiccant pouch. Replace it with a dual-bowl.
 

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Unless you need to save a dollar or so, spring for the DOT 4 or DOT 5.1. They perform better than the old standard DOT 3

NOTE: Many in the concours crowd like the silicone DOT 5. It doesn't mix with any other type fluid, and I only mention it because it is easy on paint. Guys that have a new paint job often consider using DOT 5 just to help keep the paint nice. It has performance issues that take some getting used to as well. To use it you have to first flush out all the brake lines and components to remove all of the old DOT 3/4 or 5.1

Z
 

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Unless you need to save a dollar or so, spring for the DOT 4 or DOT 5.1. They perform better than the old standard DOT 3

NOTE: Many in the concours crowd like the silicone DOT 5. It doesn't mix with any other type fluid, and I only mention it because it is easy on paint. Guys that have a new paint job often consider using DOT 5 just to help keep the paint nice. It has performance issues that take some getting used to as well. To use it you have to first flush out all the brake lines and components to remove all of the old DOT 3/4 or 5.1

Z
IMHO, the only advantages to DOT 5 are heat resistance and paint-friendliness. It's not hygroscopic, meaning it won't absorb water which you might thing is a good thing, but if your system gets water in it then it will get water in it regardless of what fluid you use. The problem with DOT 5 and not absorbing water is that the water will all collect at the lowest point in the system, since it's heavier than the brake fluid. Having a "bubble" of water sitting in the caliper or wheel cylinder in one particular spot for a while doesn't thrill me. Folks using it in a racing environment are flushing/bleeding the system regularly. If I was going to use DOT 5 I'd be bleeding the system every few months and flushing it annually, just before storage.
 

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I use Dot 5 and have for 24 years.

Yes, it is hygroscopic but then the other dot's absorb the water and still rust the lines from the inside out.

In all cases all brake fluid should be flushed every few years. That way you cannot have any of these maintenance issues.

My fastback has all its original brake lines in spite of using dot 5 for 24 years.
 

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IMHO, the only advantages to DOT 5 are heat resistance and paint-friendliness. It's not hygroscopic, meaning it won't absorb water which you might thing is a good thing, but if your system gets water in it then it will get water in it regardless of what fluid you use. The problem with DOT 5 and not absorbing water is that the water will all collect at the lowest point in the system, since it's heavier than the brake fluid. Having a "bubble" of water sitting in the caliper or wheel cylinder in one particular spot for a while doesn't thrill me. Folks using it in a racing environment are flushing/bleeding the system regularly. If I was going to use DOT 5 I'd be bleeding the system every few months and flushing it annually, just before storage.
Everything you say is 00% right. But the likelyhood of a sealed system getting water in it is pretty small. Since DOT 5 won't suck water out of the air, it's more water-free than the DOT 3 & 4's. both of which love to load up on moisture every time they go thru a heat cycle. Don't get me wrong, I don't use DOT 5 because it holds air bubbles in suspension longer than the DOT 3/4. And that makes it harder to bleed, harder to get a hard pedal. And it doesn't lend itself to to racing as well as DOT3/4. But it has its advantages. There is no perfect brake fluid.

No matter what type of brake fluid is used, I like to change it out every year or two. I've seen numerous calipers filled with ancient DOT 3 that had the consistency of peanut butter. That's what happens when the brake fluid is never changed.

Z
 

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The type of brake fluid is irrelevant if the system is leaking as it sounds like the op's is, brake fluid is low for two reasons, its leaking or you need pads/shoes replaced. As it sounds like yours was empty to the point of sucking air I'd guess leaking.
 

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The type of brake fluid is irrelevant if the system is leaking as it sounds like the op's is, brake fluid is low for two reasons, its leaking or you need pads/shoes replaced. As it sounds like yours was empty to the point of sucking air I'd guess leaking.
Well, once he determines how he lost the fluid, he's going fill it up with something, I hope.

; )

Z
 
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