What brake fluid are you running

[fetorino]

Mine has the typical chevy front discs with stock drums. This vintage should be a non synthetic. Is everyone using DOT 3 or DOT 5.1?

 

[ransil]

What ever is on sale or cheapest at walmart or advance auto.

 

[Broncobowsher]

Typically just DOT4
I don't road race and have never found a need for anything more then DOT3, but DOT4 is on the shelf for the same price so I use it.

 

[needabronco]

I like to use synthetic brake fluid, it's not supposed to absorb moisture as much as the old school stuff.

 

[Apogee]

You have a lot of options, but truthfully, an EB is a pretty easy brake fluid application since they're not really suited to heavy towing or road racing.

That said, the Castrol LMA (Low Moisture Absorbtion) isn't too bad if you don't like to change your fluid often. I typically run the Napa HD DOT3/4 fluid made by Valvoline because it's inexpensive, works well, and available everywhere. Regardless of what fluid you choose to run though, I would recommend flushing it every 1-2 years and keeping it reasonably fresh, as that will do more for the longevity of the components in your brake system than anything esle. Plus, it's a good opportunity to check all of the hoses and other items that should be inspected on a semi-regular basis for safety.

The only brake fluid I do not recommend are the silicone based DOT5 fluids. The single biggest issue with silicone fluid is that is doesn't absorb moisture, so any water that does get into the system (and it will) is immiscible with silicone, so you end up with water droplets in your brake system. Because water is denser than silicone, it settles to the bottom of the system, or the calipers in this case. Water flashes to steam at 212 degrees F...a temperature very easily achieved in almost any vehicle. Once you have steam in your calipers, pedal goes to mush along with your stopping power.

Tobin

 

[Save-A-Horse]

Man, the guy I bought my truck from put in dot 5. I'm getting ready to install hydro boost. I can't tell if my difficult manual braking is due to dot 5 "mush" or just difficult w/ 33 tires. Been like that since I bought it in 2004. My anchles swell and I can't take dat no mo.

 

[kc15842]

I've used Dot 5 in almost every vehicle I've owned for the last 25 years. No issues with mushy brake pedal or any other issues. I just don't need to worry about melting paint during any type of system maintenance.

 

[broncnaz]

I usaually run the valvoline semi synthetic mostly because its compatible with other brake fluids except dot 5. Dot 5's only real benefit is it has a higher boiling point which is good for high speed braking and it doesnt attract mositure so less change of rust in the system. I wouldnt reccomend using Dot 5 if you hit the trails a lot unless you plan on carrying a supply with you. Most of us carry dot 3 or 4 so you'd be hurting for fluid if you dont carry it.

 

[68ford]

I've used Dot 5 in almost every vehicle I've owned for the last 25 years. No issues with mushy brake pedal or any other issues. I just don't need to worry about melting paint during any type of system maintenance.

exactly, no mess or messed up paint. and have heard of several instances where it stopped leaks perminantly.
what vehicles never have brake leaking issues and are old and it doesnt matter if they have sat or rode alot? japanise motorcycles with silicone fluid.

 

[Apogee]

DOT5 silicone fluid is incompatible with most ABS systems for a reason, and that is because it gets a milkshake consistency when cycled quickly (like in an ABS hydraulic control unit). You can take a new bottle of it and shake it vigorously and see the same result, lots of little air bubbles that take a long time to dissipate.

There are multiple benefits to DOT5 silicone fluid, including it doesn't attack/lift paint, high boiling point, and higher lubricity (especially at low temperatures). The military uses DOT5 fluid primarily for the last reason since they have to meet specifications at -40 degrees or something like that. The military is also looking to move away from DOT5...so I wouldn't use them as a reason to run it yourself. The only OEM that uses DOT5 last I checked was Harley Davidson.

I'll stick with a fluid that absorbs water myself. With the advent of DOT5.1 glycol-based and synthetic fluids, the high temp rating of the Silicone fluid is no longer an advantage since there are many fluids with equally high, if not higher, temperature ratings. Then there's the water pooling issue with silicone, which basically negates the temperature rating of the fluid anyway...truthfully, I'd prefer DOT3 fluid over DOT5. The tendency for DOT5 silicone-based fluids to aerate under severe use and/or ABS is just one more nail in the coffin for me. While I wish there were alternative synthetic brake fluids that did not attach paint like a Chihuahua on a porkchop, I'll stick with the conventional DOT4/5.1 fluids until there's something better.

Tobin

 

[broncnaz]

I havent noticed any paint eating issues with the valvoline semi synthetic brake fluid. but then again I wipe up any spilled liquid. I have to look at the bottle to see if it claims anything but I would imagine it would also be less moisture absorbing.

 

[Broncitis]

I use whatever standard DOT 4 fluid is cheapest in my trail rig.

DOT 5 silicone exclusively in all our restored and custom projects for paint protection.

 

[Save-A-Horse]

Since I've inherited dot 5, I'll have to stick w/ it. Hoping that my switch from manual to hydro boost has no problems w/ air in line or turbulance causing bubbles. Guess we'll see! Using 93 Astro boost, Camaro M/C and "tee'd" line returns into P/S pump (straight shot for the steering line). I am re-using my proportional valve... can't wait, but still a little nervous.

 

[Bartonatl]

Advanced Auto Parts has their brake fluid.....buy one get one free right now.

 

[bknbronco]

STAY AWAY FROM DOT 5.

-DOT 5 doesnt mix at all with dot 3 and 4. If you spring a leak on the trail and dont have any DOT 5 with you, you CANNOT add 3/4 to your system! (it will create a sludge that cannot be flushed out)
-DOT 5 will aerate easyer than the 3/4 which on the trail could be problematic.
-DOT 5 compresses easyer than 3/4, which could make the pedal feel mushy.
-DOT 5 does not change color to tip the user of its moisture content.
-DOT 5 neither accepts nor disperses moisture leaving the system more corrosion prone, requiring regular flushing!
-DOT 5 contains no lubricity making it incompatable with some valving in anti-lock brake systems

My opinion is that DOT 5 is verry high maitance and should be only used in race applications if at all ever! Now if you want to talk about DOT 5.1 thats a different story! I had thought about using 5 until i knew more about it. Stay away!

 

[NYLES]

Since I've inherited dot 5, I'll have to stick w/ it. Hoping that my switch from manual to hydro boost has no problems w/ air in line or turbulance causing bubbles. Guess we'll see! Using 93 Astro boost, Camaro M/C and "tee'd" line returns into P/S pump (straight shot for the steering line). I am re-using my proportional valve... can't wait, but still a little nervous.

I got all that cept I use a vette m/c(4 wheel disc) dot5 works great

 

[NYLES]

STAY AWAY FROM DOT 5.

-DOT 5 doesnt mix at all with dot 3 and 4. If you spring a leak on the trail and dont have any DOT 5 with you, you CANNOT add 3/4 to your system! (it will create a sludge that cannot be flushed out)
-DOT 5 will aerate easyer than the 3/4 which on the trail could be problematic.
-DOT 5 compresses easyer than 3/4, which could make the pedal feel mushy.
-DOT 5 does not change color to tip the user of its moisture content.
-DOT 5 neither accepts nor disperses moisture leaving the system more corrosion prone, requiring regular flushing!
-DOT 5 contains no lubricity making it incompatable with some valving in anti-lock brake systems

My opinion is that DOT 5 is verry high maitance and should be only used in race applications if at all ever! Now if you want to talk about DOT 5.1 thats a different story! I had thought about using 5 until i knew more about it. Stay away!

Year 4 no problems!

 

[VT_Don]

Unlike a lot of the non sense being parroted here, allow me to offer my FIRST HAND experience. I don't have the benefit of living in an arid climate and am fanatical about my vehicles. Being a unrepentant car nut, I have replaced countless wheel cylinders, brake lines, and master cylinders due to internal corrosion. Have seen multiple systems on classic cars from extended, indoor storage encrusted with rust internally.

Owning a classic muscle car apprised at over $100K and easily capable of 160 MPH blasts, utilizing DOT 5 has been a positive move Peddle feel is rock hard. Fading is non existent, and master cylinder fluid is still untarnished several years after installation. There is absolutely no evidence of moisture contamination anywhere within the system.

Last I knew, no early Bronco had qualified for Lemans or had ABS installed. So, barring such exceptions, DOT 5 is a practical choice.