Best brake fluid to use?

[Burla]

I have a very heavy foot and Ive been meaning to do it for awhile. Now that i have the kit to switch out fluid, I'll probably do it once a year.

Then at least as a performance thing it makes sense to go with the true performance brake fluids with wet boil 600f, however this will be a costly proposition. Especially when you see the dot 3 32 ounces on sale at the parts store, it's a gut punch over the higher end dot 4's. I would "think" you could safely get two years from your 600 boil temp dot 4's, but you know what to look for, if it gets funky earlier then time to change out. Dont run it dry with that bleeder, it is very easy dyi job unless you let the brake reservoir run dry. I have a bleeder, I still use the pedal pump coke/sprite bottle method, lol.

 

[Wild one]

If you don't have one of these,you might want to pick one up.

Amazon.com : Brake Fluid Tester

 

[Burla]

If you don't have one of these,you might want to pick one up.

Amazon.com : Brake Fluid Tester

actually a great idea and will likely pay for itself if you use high quality dot 4 and 5.1 stuff rick. Set your interval with moisture level that would be the way to do it.

 

[Burla]

Nor cal spoils you, moderate temps and dry air, high end brake fluids seam to last forever. But in cold regions, humid regions, I'd bet those are flat necessary.

 

[Wild one]

actually a great idea and will likely pay for itself if you use high quality dot 4 and 5.1 stuff rick. Set your interval with moisture level that would be the way to do it.

I usually go by the tester for fluid changes Mike.I won't say it's the proper way to keep track of the fluid,it's just the way i do it,lol

I'm not sure this applies to all the cheap fluid testers,but i've got in the habit of removing the battery after each use on the one i have,as it seems to kill the battery even when not being used

 

[Docwagon1776]

You missed the spirit of what I alluded to about liability of fluid specs. WE know that the aftermarket fluid is the better of the fluids. The adversarial nature of we mere mortals against giant GM, FORD, CHRYSLER, et.al. do not have the resources to fight off "We are denying your warranty or any liability on our part due to you using a non-specified product". Perhaps that clairfies what I mean!

Nothing in the warranty mandates you use a specific brand, just that it meets the specs, which the fluid I posted does. Again, whatever helps you sleep at night but this isn't a thing.

 

[dburkard]

In texas if that is where you are at, it might be beneficial to use high end brake fluids, the argument against high end brake fluids is moisture characteristics. So research brake fluids with 600F dry boiling temp and 400f wet boiling temp. These are your entry level high end fluids, you can even go higher but at what cost. To go even higher doubles the cost of the fluid. So for sure you will want to use dot 4 over dot 3. So look at the usual suspects redline or amsoils stat sheets and these 600f fluids are true synthetic long lasting brake fluids. Maybe not the best for snow country, but warm regions such as texas good to use. Also, if you brake has been working good maybe just use prestone dot 4. No it';s not the best, but unless you tow heavy or brake heavy then you might not see much benefit in using fancy brake fluids. All dot 4 is compatable with dot 3 or other dot 4's, they will mix with no issue.

So what fluid is recommended for heavy towing & braking in the mountains of Colorado when it gets cold?

 

[Sherman Bird]

wow, way past due! One usual suspect with dark fluid is moisture, from like you say hot fluid. The problem is the high end fluids are more susptable to moisture, making the long term issue even worse. It might be a better strategy to go dot 3 or dot 4 on the lower end with boiling temps like entry level dot 4, but change it more often. High end dot 4's are great at heat, but they only make sense for a long interval when they arent used in this way. So when you use them hot like racing applications, towing heavy, or just as you say heavy braking, they will perform better then lower end stuff but you pay for that in interval. When hot fluid cools it brings in moisture. Maybe that moist air in texas a bigger issue then I thought. Instead of high end 600f dry boil, go with under 500 for moistures sake. Higher the boiling temp the higher the esters the more moisture comes from heat dissipation and transfer.

	Dry Boiling Point	Wet Boiling Point	Composition
DOT 3	205°C/401°F	140°C/284°F	Glycol Ether
DOT 4	230°C/446°F	155°C/311°F	Glycol Ether/Borate Ester
DOT 5	260°C/500°F	180°C/356°F	Silicone
DOT 5.1	260°C/500°F	180°C/356°F	Glycol Ether/Borate Ester

The green color of old fluid is from copper deposits stemming from the ABS electrolysis acting on the copper in the steel brake lines.