2006-2010 Ford Explorer Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

Every 2006-2010 Ford Explorer takes DOT 3 brake fluid. Ford's own owner guides for this generation call for Motorcraft High Performance DOT 3 Motor Vehicle Brake Fluid or an equivalent that meets the listed Ford specification, and the level should sit between the MIN and MAX marks on the reservoir. Ford's scheduled maintenance guide for these years does not print a fixed mileage for a flush, so fluid makers and brake shops treat roughly every two years as the practical interval.

Below is exactly what Ford specified by model year, why the fluid wears out even when the reservoir looks full, how to tell when yours is due, and what else to check when you open the system.

What Brake Fluid Does a 2006-2010 Explorer Use?

The fluid type never changed across this generation, but the Ford specification number printed in the owner guide did. Here is what each guide lists in its Maintenance Product Specifications and Capacities table:

In plain terms: buy a sealed bottle of DOT 3 that states on the label it meets the Ford specification for your year, or use the Motorcraft product itself. The 2008 and 2010 guides list capacity simply as "between MIN and MAX on reservoir" rather than a quart figure, because a flush uses more fluid than the system holds and a top-off only needs a small amount.

The same spec applies whether your Explorer has the 4.0L SOHC V6 or the 4.6L V8. Ford's engine compartment diagrams show the brake fluid reservoir on both engines, on top of the master cylinder. The vehicle symbol glossary in the owner guide also marks the fluid as non-petroleum based, which matters for the next section.

Fluids you should not put in it

• DOT 5 (silicone). DOT 5 is a different chemistry from the glycol-based DOT 3 this system was built for. Do not use it as a substitute or top off with it.
• Anything petroleum based. Power steering fluid, ATF or engine oil in the brake reservoir attacks the rubber seals in the master cylinder, calipers and ABS unit. Federal brake fluid labeling rules require the warning that contamination with water, dirt or petroleum products may result in brake failure. If this has happened, a flush alone is not the fix; the seals that touched the contaminant need to be replaced.
• Fluid from an old, opened bottle. The same federal label rules require the warning to keep the container tightly closed to prevent absorption of moisture. A half-used bottle that sat on a shelf with the cap loose is already partly spent.

How Often Should You Flush It?

Ford's 2008 Scheduled Maintenance Guide does not list a brake fluid replacement at a set mileage for this vehicle. What it does say is that the multi-point inspection at every visit includes checking and topping up the brake fluid level, that the brake pads, rotors, lines, hoses and parking brake are inspected at the scheduled intervals, and that fluids should be changed at the specified intervals or in conjunction with a repair. When flushing, Ford says a system must be flushed only with new fluid that is the same as the fluid required for that system.

Because the factory schedule leaves the interval open, the practical answer comes from the fluid makers. Wagner's guidance, for vehicles where the manufacturer gives no interval, is to change DOT 3 fluid every 2 years, and sooner in humid climates. Wagner also recommends changing brake fluid once its copper content reaches 200 ppm, which is what brake fluid test strips measure. That makes the best rule for an Explorer this age:

• Flush about every 2 years as a baseline.
• Flush sooner if you tow, live somewhere humid, or a test strip shows the fluid is past its limit.
• Flush any time the hydraulic system is opened for a caliper, hose, line or master cylinder replacement, since you are bleeding air out anyway.

Every 2006-2010 Explorer on the road today is well over a decade old. If you have no record of a brake fluid change, assume it is due.

Why DOT 3 Wears Out Even When the Level Is Full

Brake fluid does not get used up. The level only drops for two reasons: pad wear, or a leak. What does happen is that glycol-based fluid pulls moisture out of the air over time, and that moisture lowers its boiling point.

The federal standard for brake fluid, FMVSS No. 116, sets the minimums that show how big that drop is:

The wet figure is the fluid after it has absorbed moisture. For DOT 3 the legal floor falls from 401 F to 284 F. On a heavy SUV coming down a long grade, or towing, caliper heat can boil wet fluid, which puts vapor in the lines and gives you a pedal that sinks toward the floor. Wagner also notes that as fluid breaks down its corrosion inhibitors are used up, so internal parts of the brake hydraulics can start to corrode. On an Explorer that means the master cylinder bore, the caliper pistons and the valves inside the ABS unit.

Signs Your Explorer's Brake Fluid Needs Attention

• BRAKE warning light on with the parking brake released. Ford's owner guide says this indicates low brake fluid level and the system should be inspected immediately. It is not a top-off-and-forget light.
• BRAKE FLUID LEVEL LOW in the message center on models with the message center display. Same meaning: find out why the level dropped.
• Level below MIN. Ford notes the level drops slowly as the pads wear and rises when new brake parts are installed. A low reading with thin pads is normal wear; a low reading with fresh pads points to a leak at a caliper, hose, line or the master cylinder.
• Dark, cloudy fluid or a failed test strip. Color alone is not proof, but fluid that is dark brown and paired with a failing strip is due.
• Soft pedal that firms up when pumped, or a pedal that fades after repeated hard stops or towing. That can be air or boiled moisture in the lines.

If the level is between MIN and MAX, Ford's guidance is that no fluid needs to be added. Overfilling a reservoir with worn pads just means it will overflow when new pads push the caliper pistons back.

What to Replace While You Are In There

A fluid flush is the cheapest brake service there is, and it is the natural time to catch the parts that let moisture in or that old fluid has damaged:

• Rubber brake hoses. On a vehicle this age, cracked or swollen flex hoses are common and a direct route for moisture. See our replacement brake hoses.
• Seized bleeder screws or sticking caliper pistons. If a bleeder will not open or a caliper drags, corroded internals are likely. Replace it with a loaded brake caliper rather than fighting it.
• Master cylinder. A pedal that slowly sinks under steady pressure with no external leak points to internal seal bypass. Browse brake master cylinders.
• Pads and rotors. If the pads are near their limit, do them first and flush afterward. For this generation we carry parts such as 2006-2010 Explorer, Mountaineer and Sport Trac front ceramic brake pads, plus a full range of brake rotors and brake pads.

How Hard Is a Brake Fluid Flush on This Explorer?

A basic two-person pedal bleed is a driveway job for someone comfortable with basic tools: remove old fluid from the reservoir, refill with fresh DOT 3 that meets the Ford spec, then bleed each wheel until clean fluid comes out, never letting the reservoir run low. Follow the bleed sequence in the factory service manual for your Explorer.

Two cautions specific to this vehicle. First, it has a four-wheel anti-lock brake system, and the ABS hydraulic unit holds fluid of its own. A pedal bleed flushes the lines and calipers, but a scan tool that can cycle the ABS valves is the reliable way to push old fluid and trapped air out of that unit, especially if the reservoir was ever run dry. Second, brake fluid damages paint, so cover the fender and wipe up spills right away.

Afterward, confirm a firm pedal with the engine off and running, verify the BRAKE and ABS lamps go out after start-up, and test the brakes at low speed before driving normally.

Frequently Asked Questions

Can I use DOT 4 in my 2006-2010 Ford Explorer?

Ford specifies DOT 3 meeting its specification for your model year. The simplest safe choice is a DOT 3 labeled as meeting that Ford spec, or the Motorcraft fluid named in the owner guide. Never substitute silicone DOT 5.

How much brake fluid do I need for a flush?

Ford lists the capacity only as between MIN and MAX on the reservoir, not a fixed volume. For a full flush, buy more than you expect to use and only open new sealed bottles, since opened fluid starts absorbing moisture.

Does Ford require a brake fluid flush at a certain mileage on this Explorer?

The 2008 Ford scheduled maintenance guide lists brake fluid checks and top-ups at every visit but no fixed-mileage replacement. Wagner recommends every 2 years for DOT 3 when the vehicle maker gives no interval.

Why is my Explorer's brake fluid low if nothing is leaking?

Normal pad wear. As the pads get thinner, the caliper pistons move out and more fluid sits in the calipers, so the reservoir level drops. New pads push it back up. If the pads are fresh and the level is still falling, look for a leak.

Is the Mountaineer or Sport Trac the same?

Those models have their own owner guides. Check the Maintenance Product Specifications table in your own guide or the label on the reservoir cap before buying fluid.

Sources

1. Ford 2006 Explorer Owner's Guide - brake fluid Motorcraft High Performance DOT 3, PM-1, spec ESA-M6C25-A
2. Ford 2008 Explorer Owner's Guide - PM-1-C / WSS-M6C62-A, MIN/MAX reservoir check, BRAKE warning lamp meaning, four-wheel ABS, reservoir on 4.0L and 4.6L
3. Ford 2010 Explorer Owner's Guide - PM-1-C / WSS-M6C62-A or WSS-M6C65-A1
4. Ford 2008 Model Year Scheduled Maintenance Guide - brake fluid check and top-up at every visit, no fixed brake fluid interval, fluid change and flushing guidance
5. 49 CFR 571.116, FMVSS No. 116 Motor Vehicle Brake Fluids - DOT 3/4/5 dry and wet boiling point minimums, required container warnings
6. Wagner Brake: When to Change Brake Fluid - 2-year DOT 3 interval, 200 ppm copper threshold, moisture and corrosion effects