2006-2010 Ford Explorer Brake Caliper Problems and Replacement

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most caliper trouble on a 2006-2010 Ford Explorer comes down to three things: a sticking piston, seized slide pins, or a leaking piston seal. The fronts use a two-piston floating caliper and the rears a single-piston floating caliper, and on a truck this age the usual fix is a remanufactured or new caliper with fresh pads, plus rotors if they are worn or heat-damaged.

How the Explorer's Calipers Are Built

The fourth-generation Explorer (and its twins, the Mercury Mountaineer and the 2007-2010 Explorer Sport Trac) has disc brakes at all four corners. Both ends use floating calipers: the caliper body slides on pins in a mounting bracket, so the piston pushes the inner pad and the body pulls the outer pad in. That design is simple and reliable, but it only works when the pins slide freely and the pistons retract cleanly.

Two details matter when you shop. First, the front caliper for 2006-2010 is specific to this generation; the earlier 2002-2005 Explorer front caliper is a different part, so a caliper listed only for the older truck will not bolt on. Second, the rear caliper carried over across the 2001-2010 Explorer and Mountaineer, so rear parts listed for those years are the same design. Always confirm left versus right; the bleeder must point up once installed.

Phenolic pistons resist corrosion on the piston face, which helps in salt states, but they can chip or crack if they are pried on with a screwdriver. Compress them with a proper caliper tool or a C-clamp over an old pad.

Symptoms of a Bad Caliper

• Pulling to one side under braking. One caliper is gripping harder or releasing slower than its partner. A pull that shows up only while braking points at the brakes; a constant pull is more often alignment or tires.
• One wheel much hotter than the others. After a drive, carefully compare the wheels by holding a hand near (not on) each rim. A dragging caliper runs noticeably hotter and may smell of hot brakes.
• Uneven pad wear. Inner pad worn to the backing plate while the outer pad looks fine usually means seized slide pins. One side of the truck wearing faster than the other points at a sticking piston.
• Fluid on the inside of the wheel or tire. A wet, dark streak on the inner rim is a leaking piston seal or a loose banjo bolt. Treat this as urgent.
• Soft or sinking pedal and a falling reservoir. Ford's own guidance is to have the brakes inspected if the fluid level keeps going down or the fluid is dark.
• Clunk on first brake application. Worn pins, bushings or missing anti-rattle clips let the caliper shift in the bracket.

What Causes Explorer Calipers to Fail

Corrosion and age. These trucks are now fifteen to twenty years old. Moisture works past a torn dust boot, rust builds behind the piston, and the piston stops retracting. The same happens to slide pins whose boots have split or whose grease has washed out.

Old brake fluid. DOT 3 and DOT 4 fluids are glycol-based and absorb moisture over time. Wet fluid corrodes the caliper bore from the inside, and dark fluid in the reservoir is a warning sign. Use only the fluid type specified on the reservoir cap or in your owner's guide, and never add DOT 5 silicone fluid to a system that calls for DOT 3 or DOT 4.

Heat. Towing, mountain driving or a caliper that was already dragging overheats the piston seal. Once the seal hardens it no longer pulls the piston back, and the problem feeds on itself.

Collapsed flex hose. A rubber brake hose can deteriorate internally and act like a check valve, holding pressure on the caliper after you release the pedal. The caliper gets blamed, but the hose is the cause. If a new caliper still drags, replace the hose on that corner.

It also helps to know the recall picture. A check of NHTSA's recall database for the 2006, 2008 and 2010 Explorer returned no brake, caliper, hose or ABS recalls; the campaigns listed for those years cover items such as lighting, glass, wiper motors, seat recliners and aftermarket seat covers. Caliper failures on these trucks are wear and corrosion, not a factory campaign, but run your own VIN on nhtsa.gov to be sure nothing applies to your truck.

Diagnosing Before You Buy Parts

1. Safely raise the truck and support it on stands. Spin each wheel by hand in neutral (front) or with the parking brake released (rear). A wheel that drags hard compared to its partner has a caliper, pin or hose problem.
2. Pull the wheel and inspect pad thickness inner versus outer, the dust boot, the pin boots and the hose.
3. Remove the caliper from the bracket and try to slide each pin by hand. A pin that will not move, or moves only with pliers, is seized.
4. With the bleeder cracked open into a catch bottle, push the piston back. If it will not retract with the bleeder open, the piston is seized in the bore.
5. If the piston moves freely with the bleeder open but not with it closed, suspect the flex hose.

Pins that are merely dry can be cleaned and relubricated with high-temperature brake grease. A seized piston, a leaking seal or a pitted bore means the caliper gets replaced.

Replacing the Caliper: Parts and Difficulty

This is a moderate DIY job with hand tools, a caliper piston tool, a torque wrench and a way to bleed the brakes. Front calipers for 2006-2010 are commonly sold with the mounting bracket already attached, which saves transferring the bracket and gives you fresh bracket threads. Remanufactured units from brands such as Cardone come with new seals, bleeder screws and hardware and are pressure-tested before they ship. Shop brake calipers and Cardone remanufactured calipers by year and position.

The basic sequence:

1. Clamp or plug the hose, remove the banjo bolt, and remove the old caliper and bracket.
2. Clean the hub face and bracket mounting area.
3. Install the new caliper with new copper sealing washers on the banjo bolt, and torque the bracket bolts, caliper pin bolts and banjo bolt to the values in the factory service manual.
4. Bleed the caliper, then the rest of the system if air reached the lines. Top up with the specified fluid.
5. Pump the pedal to seat the pistons before moving the truck, then bed in the pads with several moderate stops.

The Explorer has ABS. A standard pressure or two-person bleed at the replaced corner is normally enough, but if the reservoir ran dry or the pedal stays soft, the system may need a scan-tool assisted bleed.

What to Replace at the Same Time

• Calipers in pairs. Replace both calipers on the axle so both sides grip and release the same way. Mixing one new and one twenty-year-old caliper often brings the pull right back.
• Pads. A dragging caliper usually glazes or tapers the pads. Fresh pads are cheap insurance; we carry fitted sets such as these 2006-2010 Explorer front ceramic brake pads, plus a wider range of ceramic brake pads.
• Rotors. Heat from a sticking caliper can leave hard spots, blue discoloration or runout. Check thickness against the minimum cast into the rotor and replace it if it is under spec or warped. See brake rotors.
• Hardware and hoses. New abutment clips, pin boots and, on high-mileage trucks, brake hoses round out the job. A brake hardware kit covers the clips.
• Brake fluid. Since the system is open anyway, flushing old fluid protects the new calipers from the inside.

Frequently Asked Questions

Will a 2005 Explorer front caliper fit my 2008 Explorer?

No. The 2006-2010 generation uses its own front caliper. Rear calipers are shared across 2001-2010, but the fronts changed with the 2006 redesign, so buy a front caliper listed for 2006-2010.

Do the Explorer, Mountaineer and Sport Trac use the same calipers?

For these years, yes. The 2006-2010 Explorer, 2006-2010 Mercury Mountaineer and 2007-2010 Explorer Sport Trac share the same front caliper application, and the rear caliper is shared across the Explorer and Mountaineer from 2001-2010.

Should I buy loaded or unloaded calipers?

A loaded caliper comes with pads installed, which is convenient and guarantees the pads fit. An unloaded caliper lets you choose your own pads. Either works if you replace both sides of the axle together.

Is there a recall on 2006-2010 Explorer brake calipers?

We found no brake or caliper recall for the 2006, 2008 or 2010 Explorer in NHTSA's database. Check your own VIN at nhtsa.gov, since recalls can be added at any time.

Can I just rebuild my old calipers?

Seal kits exist, but on bores that have pitted from corrosion a rebuild will not seal reliably. For most owners a remanufactured caliper with a pressure-tested bore and new hardware is the faster, more dependable fix.

Do I need to bleed the whole system after replacing one caliper?

Usually only the replaced corner needs bleeding if you kept the hose clamped and the reservoir never ran low. If the pedal is soft afterward, bleed all four corners.

Sources

1. Cardone 18-B4994 disc brake caliper - 2006-2010 Explorer/Mountaineer and 2007-2010 Sport Trac front caliper: floating, two phenolic pistons, 1.993 in, bracket included
2. Cardone 18-4754 disc brake caliper - caliper for 2001-2010 Explorer and Mountaineer: floating, one phenolic piston, 1.885 in
3. PartCatalog: Cardone 18-4754 - confirms rear position of the 18-4754 caliper
4. Cardone 18-4758 disc brake caliper - earlier 2002-2005 Explorer front caliper is a different part
5. NHTSA recalls, 2008 Ford Explorer - no brake, caliper or ABS recall listed
6. NHTSA recalls, 2010 Ford Explorer - no brake, caliper or ABS recall listed
7. Ford: How to add brake fluid - DOT 3/4 are glycol-based, never add DOT 5, service if level drops or fluid is dark