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Discussion Starter #1
I'm getting ready to do some brake work later this week and part of that will be flushing out the fluid. Does anyone have any recommendations on a certain fluid to use? I was thinking of either sticking with the Ford stuff or going with the Valvoline Syn. DOT 3&4 fluid. Also, how much fluid does it take to fully flush the system?
 

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unless its contaminated, i really dont see a point to flushing out the brake fluid.
 

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unless its contaminated, i really dont see a point to flushing out the brake fluid.
Brake fluid is like a sponge when it comes to moisture. So preventive maintenance by draining and replacing your brake fluid is a good way to prevent brake system issues such as sticking calipers, etc.

Just my 2 cents worth.
 

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FLUSH IT. Mine was terrible when I did it at 300k. Brakes are a little more sensitive now.
I used Prestone DOT3 Syn.
 

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I use Dot 4. DO3 and 4 will work.

For brake fluid service. I do one full brake peddle push of fluid for each caliper every 10,000miles.
 

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Discussion Starter #7
Thanks for the info guys. I don't think my truck has ever had it done. I've only had it a little over a year and it has just shy of 86k on it so its definitely time for a fluid change.
 

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Thanks for the info guys. I don't think my truck has ever had it done. I've only had it a little over a year and it has just shy of 86k on it so its definitely time for a fluid change.
Any other maintinance you need ot do? trans? air filter?
 

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ya just flush until the color turns pee yellow..if you havent done it for 86k miles, its prob orange or reddish..DOT 3 or DOT 4 works fine. I flush mine once a year and even after a year, it's between yellow and orange.
 

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Discussion Starter #10
Any other maintinance you need ot do? trans? air filter?
All the other major stuff has been done. I just hadn't done the brake fluid since I knew a brake job was coming soon for the rear so I just put it off until now. The next thing is just fuel filters when I do my oil change. Thanks for asking about other Mx items though. :thumb:
 

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I may be recalling this wrong, but isn't DOT 4 silicon based and DOT 3 is glycol based. Seem to remember that DOT 4 has a higher affinity for air whereas DOT 3 has a higher affinity for water.
 

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when you flush your system did you "manually" pump the brakes or
do you have to use a power bleeder on the ABS system ??? I changed
calipers, had rotors turned - eveything fresh. Can't get the brakes to
pump up manually... got the air out of the lines but no hard pedal.

Any thoughts ....
 

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I've always used one of those hand powered bleeders that suck out the old fluid.
 

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I've posted in different forums, so I'll grab some of my posts and include them here if you don't mind. Today I'm not in the mode for writing.

_

The entire brake fluid thing has gotten crazy in the USA.

Going back a few decades, during on-going discussions within SAE we discussed the issue but also noted that many did not follow the procedure that was laid out in the owner's manuals, and at times people put petroleum-based products into the master cylinder to keep it up. Also, there were discussions about how to warn owners that the brake pads were wearing out. The initial focus was using the mechanical "squealers" that attached to the pads, but that was ineffective. Also during the '90s, there were instances of pickup trucks losing their brakes due to fluid boil. It happened on other vehicles too, but the disc/drum pickup trucks with their front bias were really bad.

At the end of the day, the SAE committees came up with a compromise, and like all compromises, everyone left the table unhappy.

Because of the lack of maintenance, to address the brake fluid boil the adaptation of phenolic pistons to insulate the fluid from the brake pads was universally adopted across all weight classes and vehicle manufacturers. Our company came up with an insulating layer that went between the friction material and steelback. That was incorporated into the early '99-04 brake pads, and initially, even the front pads had a stainless steel heat shield that was added by the caliper manufacturer.

There also were rubber compound changes to the brake hoses and M/C diaphragm to make them more resistant to air transfer. And there were additive packages to improve the life of brake fluid.

To address the pad wear-out warning, a float sensor was incorporated in all master cylinders. That proves to be a very ineffective solution as you can have individual foundation brakes wear out pads due to movement failures or in the aftermarket a change in the wear balance due to friction material formulation changes that let the front or rear brakes wear out first. The volume change in the master is supposed to account for all pads in a combined manner. It doesn't work well when you have one foundation brake on a corner go steelback to the rotor as many of us have. No wear-out warning light.

So the check-off list rids us of needing to do the periodic maintenance of brake fluid. They didn't follow this in Europe, European vehicles still have the schedule in the owner's manual, along with the need for DOT 4 in most cases. In about 3-4 years DOT 3 and 4 end up at the same boiling point.

Or does it. It certainly took the obligation out of the manufacturer's hands and allowed everyone to improve their JD Powers score for maintenance, which actually was the first blood.

Brake fluid turns dark due to water and copper absorption. Where does the copper come from? The brazing of the tubes from the flat stock into a tube. It's better at this then it was, but by about 6 years it's where you don't really want it, the additives for anti-corrosion have worn out depending on temp exposure. But the SAE guess was that brakes wore out around 30-40k miles, people would put on new calipers, brake fluid would be changed, and maintenance solved.

So we might not have the same worry about fluid boil that we used to, unless you have over-extended the original design load, changed to a more metallic brake pad, or have issues of hysteresis from slide pins, pistons hanging, or pads rusting in the brackets.

But although you can get away with it, I wouldn't be one to wipe my hands and say "no problem here" based on the owner's manual, it certainly didn't have the best practice in mind.

The Europeans, BMW, VW, Audi ... the guys that run the alps, sort of normal driving but with a trailer, every 2 years or 20-30k miles, DOT 4. But what do they know ......

Broken record.......

The US manufacturers through some discussions within SAE have dropped brake fluid changes in their scheduled maintenance lists. Europeans have stayed on course.

The thought pattern behind this is that the general public has a tendency to put the wrong fluid in reservoirs. So let's make the reservoir big enough to hold all the fluid each circuit will need until brake wears out, and use the fluid level via a level sensor the warning system that the brakes have worn out. Therefore the repair tech will be the informed person who will do the fluid maintenance. Even the brake fluid boil tests we did on vehicles were geared around fluid that had 3-year saturation of water content.

This is also the reason that phenolic pistons have generally replaced all steel caliper pistons, they don't transfer heat to the fluid as readily, lessening the issue of the fluid boil.

Here's the problem from someone who has had to run the vehicle prove out tests for the OE side, while also being vehicle test active on the aftermarket side. The composition of aftermarket materials may have a higher metallic content then the OE material, and the tests do not incorporate the fullest trailer tow situation where the trailer brakes may not be optimum. Combine those two and your back into brake fluid boil territory if there is no proper maintenance. Higher metallic friction material has a higher rate of thermal transfer.

Other problems with lack of brake fluid maintenance are rust. ABS valving is no longer an issue, so worrying about the ABS is not the problem. Calipers can be, but the caliper issue tends to be oxidation behind the dust boot causing a loss of freedom from boot/o-ring/piston interaction. For me the bigger problem is oxidation in the master cylinder chamber where the rubber cups typically do not travel, leaving the cup nicking oxidation. Most times with a poorly maintained system this only becomes a problem during the bleeding during newly installed components. The person behind the steering wheel pushes the brake pedal fully during the bleeding event, and the cups get nicked. Now the owner complains the brake pedal is long despite all the bleeding and a new master cylinder becomes the remedy.

For me, I worry more about a panic stop situation, where the drivers push harder and therefore deeper into the master cylinder to achieve maximum deceleration. Just the time when you need full braking. Not an often found situation, but not the prospect I care to encounter.

So from me, the recommendation is to replace every three years. It doesn't have to be the anal have to get everything changed, but improvement still. Almost everything designed in the US is around DOT 3 fluid, just standard fluid without all the fancy formulations. DOT 4 has a higher boil point but tends to drop its boiling point faster then DOT 3, so if you don't do maintenance in 3-4 years it will all be the same.

Europe still likes DOT 4 best. But they still have brake fluid as a maintenance item.
 

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So how much brake fluid do you need to flush the entire system?

Four years ago, when my MighyVac and I changed the brake fluid, I used 2.25 quarts until it became clear. Some have recommended 4 quarts. I got a good workout that day pumping the MightVac,
 

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Around 2 and 1/2 quarts for me. I use up 2 of the 32 fl. oz bottles (which is 2 quarts) and then need usually need a little more. Basically the same as ChrisSki posted above. I do it about every 3 years.
 
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