By Core Brake Parts Tech Team — Circleville, OH warehouse
Most brake caliper trouble on a 2004-2012 Mitsubishi Galant is not a dead caliper at all. It is a slide pin that has lost its grease and started to bind, or a piston that no longer retracts cleanly, and the result is a pull, a hot wheel, a smell, or one pad worn far thinner than its partner. Diagnose which one you have before buying parts: a sticky pin is a cleaning and grease job, while a seized or leaking piston means a replacement caliper.
How the Galant's Caliper Setup Works
The ninth-generation Galant sold in North America from 2004 through 2012 was built with disc brakes at all four wheels. Published specifications list front and rear disc brakes on the base 2004 DE, and the same on the 2009 ES, so unlike many economy sedans of that era you are dealing with four calipers, not two calipers and a pair of drums. Anti-lock brakes were not available on the 2004 DE, while later cars such as the 2009 ES carry four-wheel ABS with electronic brake-force distribution.
Each corner uses a sliding (floating) caliper design: hydraulic pressure pushes the piston out against the inner pad, and the caliper body slides on two guide pins to pull the outer pad against the rotor from the other side. That sliding motion is the weak point. If either pin sticks, the caliper can no longer center itself, and one pad drags or does all the work.
The rear calipers deserve extra attention because they sit where road spray and salt collect, and they do less work than the fronts, so corrosion has more time to set in between services.
Symptoms of a Bad or Sticking Caliper
- Pull to one side under braking - one caliper is applying harder or later than the other on the same axle.
- Pull while cruising with no brakes applied - a caliper is dragging and not releasing.
- One wheel much hotter than the others after a drive, often with a hot-brake smell. Hold a hand near (not on) each wheel after a short drive to compare.
- Uneven pad wear - the inner pad worn to the backing plate while the outer pad looks healthy, or pads tapered from end to end. ADVICS lists excessive pad wear and pad noise as the classic signs of a sticking slide pin.
- Fluid on the inside of the wheel or tire - a leaking piston seal or bleeder. This is a stop-driving condition.
- A low or spongy pedal together with a falling fluid level in the reservoir.
Common Causes on a High-Mileage Galant
| Cause | What you find | Usual fix |
|---|---|---|
| Dry or rusted slide pins | Pin will not slide by hand, rust on the pin, tapered or uneven pad wear | Clean or replace pins, re-grease, new boots |
| Torn pin boots | Split or swollen rubber boot, water and grit inside the bore | New boots and pins; replace the caliper if the bore is pitted |
| Corroded piston | Piston will not push back, or returns slowly; dragging wheel | Replace the caliper |
| Failed piston seal or dust boot | Wet caliper, fluid on the tire, dropping reservoir level | Replace the caliper and bleed the system |
| Old, wet brake fluid | Dark fluid; internal corrosion at more than one corner | Flush the fluid when replacing calipers |
ADVICS traces slide pin sticking to pins that rust after running out of grease and to pin boots and sleeves damaged by heat and friction. Their fix is to replace a corroded pin, replace damaged boots and sleeves, and use an anti-rust grease on the pin and a rubber-safe grease on the boot and sleeve. Ordinary petroleum grease on rubber parts can make them swell, which recreates the problem you just fixed.
Brake fluid age matters too. Brake fluid is hygroscopic: it absorbs moisture from the air over time, which lowers its boiling point, and ADVICS notes DOT 3 formulas reach that saturated point sooner than DOT 4. Moisture inside the system is also what attacks piston bores from the inside, which is why a car that has never had a fluid flush tends to have more than one tired caliper.
How to Diagnose Before You Buy
- Lift the car safely and support it on stands. With the transmission in neutral and the parking brake off, spin each wheel by hand; a wheel that is noticeably harder to turn than its partner on the same axle is dragging.
- Remove the wheel and look at both pads. Uneven inner-to-outer or tapered wear points at the slide pins; fast but even wear on one side of the car points at the piston.
- Unbolt the caliper and try to slide each pin in and out of its bore. It should move smoothly with light hand pressure.
- With the old pads out, push the piston back with a C-clamp and an old pad as a spreader while watching the reservoir so it does not overflow. A piston that will not move, or moves in jerks, is seized.
- Check the piston dust boot and the caliper body for wetness. Any fluid means the caliper is done.
- If a rear caliper drags only after the parking brake has been used, check the parking brake cable and mechanism on that side before condemning the caliper.
The Fix: Which Parts to Replace Together
If the pins and bores are clean and the piston moves freely, a thorough pin service with new boots and new pads may be all that side needs. If the piston is seized, leaking, or badly pitted, replace the caliper. Replace calipers in pairs on the same axle so both sides apply and release at the same rate; a new caliper on one side and a tired original on the other invites the same pull you were trying to cure.
A dragging caliper overheats the pads and rotor at that corner, so plan on fresh pads and usually rotors on the axle you are working on. Our 2004-2012 Mitsubishi Galant front and rear brake kit covers rotors and pads for both axles, which is the simplest way to reset a car whose brakes have been dragging. You can also shop replacement brake calipers, brake hardware kits with new clips, and flexible brake hoses, since a hose that has collapsed internally can hold pressure on a caliper and mimic a seized piston.
Remanufactured calipers are a solid choice for this car. Cardone states its reman calipers receive new seals, boots, banjo bolts, washers and bleeder valves where applicable, and are end-of-line tested for seal integrity, with installation hardware and mounting bracket included where applicable. Match the part to your car's side and axle and compare it with the old caliper before you install it.
How Hard Is the Job?
On a Galant a front caliper swap is a moderate DIY job for anyone who has already done pads: the guide pin bolts, the mounting bracket if you are changing it, and the brake hose fitting. Rears are similar but involve the parking brake, so read the procedure for your year and trim before you start. What makes it more than a pad job is the hydraulics:
- Use new sealing washers on a banjo fitting and torque every bolt to the value in the factory service manual.
- Use the brake fluid grade printed on the reservoir cap or in the owner's manual, from a freshly opened sealed container.
- Bleed the system completely after opening a line, and bleed all four corners if the fluid is old or dark.
- Pump the pedal until it is firm before moving the car, then bed in the new pads.
If you are not comfortable bleeding brakes, or the pedal stays soft on an ABS-equipped car after a normal bleed, have a shop finish the job.
Recalls to Know About
NHTSA's recall database shows no caliper recall for the 2004-2012 Galant. It does list campaign 05V409000 for the 2005 Galant, covering ABS-equipped cars whose brake master cylinder could let fluid bypass internally during stopping, causing a partial loss of braking; dealers replaced the master cylinder. If you own a 2005 with ABS and a sinking pedal, run your VIN through NHTSA's recall lookup before you blame a caliper. If the recall work is done and the master cylinder is failing again, see our brake master cylinders.
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Shop Brake Calipers →Frequently Asked Questions
Does the 2004-2012 Galant have rear calipers or rear drums?
Published specifications list four-wheel disc brakes on this generation, including the base 2004 DE, so it has calipers at all four corners.
Can I replace just one caliper?
You can, but replacing both calipers on the same axle is the better practice so both sides apply and release evenly and the car does not pull.
Why did my new pads wear out on only one side?
That is the classic sign of a sticking slide pin or a piston that is not retracting. Service the pins or replace the caliper, or the new pads will wear the same way.
Do I need to bleed the brakes after changing a caliper?
Yes. Any time a hydraulic line is opened, air enters the system. Bleed until you get clean, bubble-free fluid and a firm pedal.
Should I replace the rotors if a caliper was dragging?
Usually. A dragging caliper overheats the rotor, which can cause uneven deposits and vibration. Measure it; if it is at or below the minimum thickness cast on the rotor, or it pulses under braking, replace it.
Sources
- CarSpecs - 2004 Mitsubishi Galant DE specifications - front and rear disc brakes; ABS not available on the DE
- CarSpecs - 2009 Mitsubishi Galant ES specifications - four-wheel disc brakes with ABS and EBD
- ADVICS - Troubleshooting caliper slide pin sticking - symptoms, causes and grease recommendations
- ADVICS - Brake fluid boiling points - brake fluid absorbs moisture; DOT 3 saturates sooner than DOT 4
- Cardone - Remanufactured brake calipers - new seals, boots, bleeders and end-of-line seal testing
- NHTSA - Mitsubishi Galant recall data - campaign 05V409000 master cylinder recall
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