2014-2020 Mitsubishi Outlander Brake Noise: Squeal, Grinding and Pulsation Causes

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most brake noise on a 2014-2020 Mitsubishi Outlander comes from one of four places: worn front pads hitting their wear indicator, tired rear pad clips that let the pad knock or squeak, a sticking rear caliper, or rotors that have gone out of true. Squeal usually means vibration or a wear indicator, grinding means metal on metal, and pulsation in the pedal points at the rotors or hub faces. Mitsubishi issued a service bulletin and two safety recalls that involve the rear brakes on this generation, so check those before you buy parts.

How the Outlander's brakes are laid out

This generation of Outlander uses disc brakes at all four corners. On models with the mechanical parking brake, the parking brake is built into the rear caliper: a lever on the caliper turns an operating shaft that pushes the piston out, and an automatic adjuster takes up pad clearance as the pads wear. NHTSA recall filings describe 2014 as the model year that adopted this rear caliper with the built-in parking brake. That design matters for noise diagnosis, because a rear caliper whose shaft or adjuster is sticking can drag the pads and make heat, noise and uneven wear.

At both ends the pads ride in a caliper bracket on pad clips (abutment clips) that hold them snug while letting them slide, and the pads carry a mechanical wear indicator tab. Those clips turn out to be a big part of the story on this vehicle.

Squeal: what it means and how to find it

Brake noise, as Wagner's technical team puts it, is vibration you can hear. Every brake vibrates; the shims, clips and caliper mounting are there to damp it before it reaches an audible frequency. When those parts rust, loosen or lose their spring, the vibration gets through as a squeal.

• Steady high-pitched squeal that changes when you touch the pedal: often the pad wear indicator tab touching the rotor. Pull the wheel and check the pads. If they are down near the tab, replace them now.
• Squeal only when braking lightly, pads still thick: vibration. Look for missing or delaminated shims, dry pad ears, worn clips, and glazed or ridged rotors.
• Squeak or knock from the rear at low speed, or when shifting between Drive and Reverse: this is the exact complaint in Mitsubishi TSB-19-35-002REV, covered below.
• Squeal in the first few hundred miles after new pads: EBC notes new-pad squeal usually shows up in the first 200 to 500 miles and fades as the pads bed in. If it continues past that, a few firm stops on a safe road usually finish the bedding.
• Brief scraping after the car sits in rain: surface rust on the rotors. Bendix notes this should clear on its own within a few stops.

The rear brake knock and squeak bulletin (TSB-19-35-002REV)

Mitsubishi first issued TSB-19-35-002 in January 2019 for a metallic knocking sound from the rear disc brakes on uneven roads or when braking at low speed. The September 2019 revision added a squeaking sound and the Drive-to-Reverse and Reverse-to-Drive symptom, and it limited Outlander coverage to 2014-2019 models with the mechanical parking brake (2011-2019 Outlander Sport/RVR are also covered).

The cause Mitsubishi gives: the rear brake pad clips lose strength with use, so the rotor pulls the pad inside the bracket and it clunks or squeaks as it shifts. The fix is to remove the rear pads, brush-clean the pads and the clip mounting areas of the caliper support, install new upper and lower clips, and grease the pad where it contacts the bracket using the grease supplied with the new clip set. The bulletin stresses applying the grease evenly so the pad contact areas are fully covered.

Practical takeaway: when you do rear pads on one of these Outlanders, never reuse the old clips. A fresh brake hardware kit with new clips, plus the correct lubricant on the pad ears, is the same cure the dealer applies.

Grinding: stop driving on it

Grinding is the sound of metal cutting metal. Once the friction material is gone, the steel backing plate scores the rotor, and every mile makes the rotor worse. Other grinding sources are a stone or debris trapped between the rotor and the splash shield, or a rear caliper that is not releasing. Diagnose it this way:

1. Pull the wheel and look at pad thickness on both the inner and outer pad. The inner pad often wears first and is hard to see through the wheel.
2. Check the rotor face for deep grooves or a shiny ring of bare steel from the backing plate.
3. Spin the wheel by hand with the car raised. A rear wheel that is hard to turn with the parking brake released points to a sticking caliper or parking brake shaft.
4. Look behind the rotor for a trapped stone or a bent dust shield.

If the backing plate has touched the rotor, plan on replacing brake rotors along with the pads. A rotor that is scored past safe machining limits will chew up new pads and keep making noise.

Pulsation: rotors, hubs and runout

A pedal that pulses or a steering wheel that shakes during braking comes from the pads meeting a rotor surface that is not uniform. Wagner lists the usual culprits: excessive rotor runout, loose wheel bearings, and rust on the hub face where the rotor seats. Rust or scale between the hub and rotor tilts the rotor slightly, the rotor wobbles as it turns, the pads wear it unevenly, and within a few thousand miles you feel it in the pedal.

Fixing pulsation properly means more than new rotors:

• Clean the hub face to bare, flat metal before installing a rotor.
• Check wheel bearing play.
• Torque the lug nuts in a star pattern to the factory specification with a torque wrench, never with an impact gun alone.
• Bed the new pads in so they lay down an even transfer layer.

A dragging caliper also causes pulsation by overheating one rotor, which brings us to the recalls.

Recalls that affect rear brake noise and drag

Run your VIN through the NHTSA recall lookup or a Mitsubishi dealer before paying for rear calipers. If the recall work was never done, the dealer repair is free. If the car is past recall coverage and a rear caliper is dragging, replacement brake calipers are the fix; rebuilding a corroded parking brake shaft is rarely worth the labor.

What to replace, and how hard the job is

For a noisy Outlander, a complete job on an axle is pads, rotors if they are scored, worn or causing pulsation, and new clips every time. Choose quality ceramic pads with shims attached, such as our 2014-2020 Mitsubishi Outlander front ceramic brake pads, or browse all brake pads. Wagner and Bendix both point out that where the pad has a bonded shim, a light coat of the correct lubricant on the back of the shim helps damp noise; for pads with an integrally molded insulator, Wagner says to put no compound on the insulator at all. Follow the instructions in the box for the pad you buy.

Also service the slides. Bendix and EBC both call out seized or dry caliper slides as a source of drag, uneven wear and noise. Clean them, check the boots, and relube with a high-temperature brake grease.

Front pads and rotors are an entry-level DIY job with basic hand tools, a piston tool and a torque wrench. Rear pads are similar in effort, but because the parking brake is built into the caliper, follow the service manual procedure for retracting the piston and resetting the parking brake. Forcing the piston the wrong way can damage the adjuster. After any brake job, pump the pedal before moving the car and bed the pads in: Wagner recommends about 20 slowdowns from 50 mph to 20 mph with light pedal pressure, allowing about 30 seconds between each.

Frequently Asked Questions

Why do my Outlander's rear brakes clunk when I shift from Drive to Reverse?

That matches Mitsubishi TSB-19-35-002REV. Weakened rear pad clips let the rotor pull the pad in its bracket. New upper and lower clips and grease on the pad contact points fix it.

Is brake squeal on new pads normal?

Some squeal during bedding is common. EBC says it usually happens in the first 200 to 500 miles. If it continues, check shims, clips and lubrication, and do a few firm bedding stops.

Can I just resurface the rotors to stop pulsation?

Only if they stay above the minimum thickness stamped on the rotor, the hub face is clean and the bearing is tight. Otherwise the pulsation returns. Many owners replace the rotors instead.

Does the parking brake recall cover my Outlander?

Recall 18V-070 covers 2014-2016 Outlanders and 20V-741 covers certain 2016 models. Check your VIN with NHTSA or a Mitsubishi dealer; completed recalls are not repeated.

Should I replace front and rear brakes together?

Not necessarily. Replace pads in axle sets (both sides at once) and inspect both axles. Fronts usually wear faster, but the rear calipers on these models deserve a close look for drag.

Sources

1. Mitsubishi TSB-19-35-002REV (via NHTSA) - rear brake knocking/squeaking symptoms, affected years, clip replacement and grease fix
2. Mitsubishi TSB-19-35-002 original (via NHTSA) - original January 2019 knocking complaint and cause
3. NHTSA Part 573 Recall Report 18V-070 - 2014-2016 rear caliper parking brake shaft corrosion and auto-adjuster defect
4. NHTSA Part 573 Recall Report 20V-741 - 2016 operating shaft coating defect and caliper replacement remedy
5. Wagner Brake - Brake System Noise - vibration as noise source, runout and hub rust, shim lubrication, burnish procedure
6. EBC Brakes - Brake Squeal Causes and Cures - new-pad squeal window and caliper slide service
7. Bendix - Diagnosing and Rectifying Brake Noise - seized slide pins, shim lubrication, surface rust noise