CSX4753 help with brakes

[Dwight]

I worked on a B&B with Ford brake a few years back and it would not stop. Well it did but took 200 - 300 ft. Scary!
I changed the brake fluid for Dot 3/4 synthetic. Then I could lock up the tires.

[BigGuy]

Dot 3 is fine doing a switch to 4, can make cottage cheese worse.
My .02

[Dwight]

What Is Brake Fluid Made Of?
If you look at the chemistry behind most brake fluid, it comes from the combination of various types of glycols, which are basically a mixture of non-petroleum and other alcohol-based fluids. After a mixing process, the chemical name gets shortened to “polyglycol”. In addition, there are also high-grade silicone-based fluids, which cannot be mixed with any other type of fluid. So whether it's used in the brake or clutch system, it's important to understand the differences between these common types of brake fluid.

The brake fluid must maintain specific properties. Our brakes can get hot, sometimes up to 1200 degrees, so the fluid needs a high boiling point. Also, because our vehicles experience seasons just as we do, it’s important to have low freezing point as well. On top of maintaining both extremes, it's designed not to damage any rubber components in the brake system.

brake fluid properties
As a result, the chemical properties found in most brake fluids can permanently dull or damage paint. So be sure to handle with care and be quick to clean any accidental overspills. Brake fluid is hydroscopic, meaning it has a natural tendency to absorb moisture. And over enough time the added moisture can result in corrosion build up or a decreased boiling point. It’s never a bad idea to change your brake fluid every couple of years and try not to leave your reservoir cap off any longer than needed.

DOT 3 vs DOT 4
DOT 3

DOT 3 is the most common type of brake fluid used in domestic cars and trucks. According to the Society of Automotive Engineers (SAE), DOT 3 can absorb 2 percent of its volume in water every year. Over enough time excessive moisture will cause corrosion in the brake system which can lead to issues like vapor-lock or a spongy pedal.

DOT 4

DOT 4 is formulated for use by all vehicles, it has a higher boiling point than DOT 3 and it does not absorb moisture as fast. DOT 4 and DOT 3 are interchangeable, however it's best to avoid adding DOT 3 fluid to a system that already uses DOT 4. It's the preferred type of fluid used for street and high performance applications. Almost all of the brake fluids Speedway offers from Afco, Wilwood, and Ultra Lite will meet or exceed DOT 4 requirements.


I added the bold print so it would be easier for the speed readers
Dwight

[Dwight]

there is a 45 degree F difference in the boiling point of Dot 3 and 4.

Not enough to make any difference on a street car.

[Dwight]

found this also


In practice, you can go up in DOT rating as long as it is the same base material. Mainly regarding your comment about mixing glycol based DOT 3 and glycol based DOT 4 is half true/misleading. You can mix the two and it will suffice for a system needing the DOT 3 rating but will boil and therefore have moisture/system issues in a system requiring DOT 4. Why does that matter? You can flush a DOT 3 system and fill it with DOT 5.1, the DOT standard is just a specification for characteristics of the hydraulic fluid. – finleyarcher Sep 26 '17 at 19:51
1
The glycol vs silicone is true because they don't actually mix, so you have two separate fluids acting in the system, which generally results in inconsistent hydraulic pressure as the fluids resist each other. It would be just like mixing engine oil with water. – finleyarcher Sep 26 '17 at 19:52
1
@finleyarcher I wondered whether that was the case. I have since heard of cases where the rubber s4als whcih 'prefer' one type disintigrate if they're used with the other. Eg on my morris traveller, it expects Glycol-based fluid. If I put silicone in (even if all new gear and fluid), the rubber seals might not like it. – user2808054 Feb 13 '19 at 10:22

[CSXBill]

Originally Posted by Dwight

What Is Brake Fluid Made Of?
If you look at the chemistry behind most brake fluid, it comes from the combination of various types of glycols, which are basically a mixture of non-petroleum and other alcohol-based fluids. After a mixing process, the chemical name gets shortened to “polyglycol”. In addition, there are also high-grade silicone-based fluids, which cannot be mixed with any other type of fluid. So whether it's used in the brake or clutch system, it's important to understand the differences between these common types of brake fluid.

The brake fluid must maintain specific properties. Our brakes can get hot, sometimes up to 1200 degrees, so the fluid needs a high boiling point. Also, because our vehicles experience seasons just as we do, it’s important to have low freezing point as well. On top of maintaining both extremes, it's designed not to damage any rubber components in the brake system.

brake fluid properties
As a result, the chemical properties found in most brake fluids can permanently dull or damage paint. So be sure to handle with care and be quick to clean any accidental overspills. Brake fluid is hydroscopic, meaning it has a natural tendency to absorb moisture. And over enough time the added moisture can result in corrosion build up or a decreased boiling point. It’s never a bad idea to change your brake fluid every couple of years and try not to leave your reservoir cap off any longer than needed.

DOT 3 vs DOT 4
DOT 3

DOT 3 is the most common type of brake fluid used in domestic cars and trucks. According to the Society of Automotive Engineers (SAE), DOT 3 can absorb 2 percent of its volume in water every year. Over enough time excessive moisture will cause corrosion in the brake system which can lead to issues like vapor-lock or a spongy pedal.

DOT 4

DOT 4 is formulated for use by all vehicles, it has a higher boiling point than DOT 3 and it does not absorb moisture as fast. DOT 4 and DOT 3 are interchangeable, however it's best to avoid adding DOT 3 fluid to a system that already uses DOT 4. It's the preferred type of fluid used for street and high performance applications. Almost all of the brake fluids Speedway offers from Afco, Wilwood, and Ultra Lite will meet or exceed DOT 4 requirements.


I added the bold print so it would be easier for the speed readers
Dwight

Great info!

[427Larry]

Get Porterfield Semi-Metallic Pads. If you can not find them for some reason, call McCluskey LTD in California, 310-375-1234.