Brake Fluid. The types.

[BroncLander]

Back in the day we had DOT 3. And DOT 4 was for heavy vehicles like motorhomes.

DOT 3 and DOT 4 both have a tendency to absorb water from the atmosphere, so always make sure to keep the cap tightly on the bottle. If you have old brake fluid, it's probably safe to assume it's contaminated with water and would eventually rot your brake line from the inside out and cause evaporation bubbles in hot weather.

DOT 3 is basic and ok for light cars but in my experience, a big car like a Camaro or Galaxy or a Truck, you'll never get brake fade with DOT 4 as it has a way higher boiling point.

DOT 5 is Silicone based. So you cannot mix it with old DOT 3 or DOT 4. If you build a whole new system, you might want to opt for DOT 5 as it is the best. But you cannot mix the 2 types. Once you fill a new brake system with a type of brake fluid, you should stick to it.

 

[fastpakr]

DOT 5.1 is also worth mentioning - specs like 5 but compatible with 3/4.

 

[sgtsandman]

I really need to look into getting fluid for the 2019. I forget which type it is but it is not easy to find. No stores carry it from what I see. It’s the dealership or mail order online.

 

[DILLARD000]

...DOT 3 is basic and ok for light cars
but in my experience, a big car like a Camaro or Galaxy or a Truck,
you'll never get brake fade with DOT 4 as it has a way higher boiling point...

Yep, preference here for brake fluid is DOT4, like that higher temp rating compared to stock DOT3.
In a 2001 4.0L & 2008 3.5L, suction out Brake reservoir every 4kMiles\6mths
then refill with fresh DOT4; dispose of old fluid along with routine Engine Oil+Filter changes.

 

[BroncLander]

Yep, preference here for brake fluid is DOT4, like that higher temp rating compared to stock DOT3.
In a 2001 4.0L & 2008 3.5L, suction out Brake reservoir every 4kMiles\6mths
then refill with fresh DOT4; dispose of old fluid along with routine Engine Oil+Filter changes.

I lost my brakes in a Trans Am driving down a mountain pass with some insane switchbacks. It was when I began using DOT 4 in anything Automatic or heavy. It's only a couple bucks more and well worth it for those 3 times it'll ever make a difference

 

[snoranger]

Remember DOT4 is more hygroscopic than DOT3… meaning it will absorb water faster than DOT3 and needs to be changed more often.

Yes, the correct word is hygroscopic.

 

[19Walt93]

My 2016 Escape says "DOT 4" on the master cylinder cap, my Ranger and Mustang both run DOT 3 and all of them get the fluid flushed out every 2-3 years. I replaced the whole brake system on my Mustang when I dragged it out of a barn in 1990. I rebuilt the calipers and replaced the rear cylinders in about 2018. I've replaced the hoses about every 10 years as a precaution and I replaced the master cylinder with an aluminum one from a 92 Ranger a few years ago because I couldn't find paint that would stay on the iron one. If you run what it calls for and maintain it, it works fine.

 

[dvdswan]

Yes, the correct word is hygroscopic.

But one would hope there is no "air" in your brake lines....

 

[pjtoledo]

the air contact is in the reservoir.

 

[Shran]

I've never had a problem using brake fluid from an opened container, even one I opened years ago (and kept the lid on of course.) Fluid changes can't hurt but personally I have never done that unless I'm replacing a part.

Allegedly using DOT-5 in a system designed for DOT-3 or 4 can cause problems as well. I would be tempted to just use whatever the OEM spec is instead of trying to prevent issues and running DOT-5.

 

[Ranger850]

I've seen what can happen when just a little bit of a petroleum based product get into the brake system. Rubber swells and contorts, blocking the passage for fluid.

 

[sgtsandman]

The Owner's Manual for the 2019 calls for DOT 4 Low Viscosity.

 

[19Walt93]

I've seen what can happen when just a little bit of a petroleum based product get into the brake system. Rubber swells and contorts, blocking the passage for fluid.

I have to and it ain't pretty. There was a Jiffy Lube less than a mile from our shop and their "technicians" periodically topped up the brake fluid with power steering fluid. Every bit of rubber in the brake systems had to be replaced. We made a lot of money fixing cars they'd "serviced".

 

[Ranger850]

I have to and it ain't pretty. There was a Jiffy Lube less than a mile from our shop and their "technicians" periodically topped up the brake fluid with power steering fluid. Every bit of rubber in the brake systems had to be replaced. We made a lot of money fixing cars they'd "serviced".

Exact same story for me. It got to where the mechanic would say " Did you just come from Jiffy Lube?' when trying to diagnose the problem.

 

[sgtsandman]

I stopped trusting quick change oil places a long time ago. The quality of the "mechanic" is pretty much equivalent to a train monkey. They know enough to be dangerous and their possibly well intended actions may end up in a costly repair because they didn't know any better. Plus, if you are getting anything more than a conventional oil change, the prices they charge are outrageous.