2020 GMC 2500 Brakes Squeak: Common Causes and Fixes

If you’re the owner of a 2020 GMC 2500 and have been plagued by a bothersome high-pitched squealing coming from your brakes, you’re not alone. 2020 GMC 2500 Brakes Squeak is one of the most common complaints brought into repair shops, and the stout towing machines that GM’s 2500 trucks are known for certainly put plenty of stress and wear on their brake systems over time.

As someone who has personally worked on a fair share of these heavy duty trucks in my career as a technician, I’ve seen just about every type of brake issue imaginable, including chronic 2020 GMC 2500 brake squeaks.

In this blog post, I want to share some of the most common causes behind those squeaks, as well as provide some tips and tricks I’ve learned over the years to finally eliminate the noise and get your brakes back to smooth, quiet stopping.

Brake Pad Wear

2020 GMC 2500 Brakes Squeak

One of the most common causes of 2020 GMC 2500 Brakes Squeak is worn brake pads. Over time, the friction material on the pads gets worn down and starts making contact with the brake rotors, resulting in that annoying high pitched squeal. New brake pads typically have smooth surfaces coated in friction modifying compounds that help prevent noise. But as the pads wear, those compounds wear away exposing the rough pad backings that grind and squeak against the rotor.

You can check the thickness of your brake pads by locating the wear indicator slot or notch molded into the friction material. When you can see the indicator through the opening, the pad is worn out and needs to be replaced. Low or dusty pads can also do 2020 GMC 2500 Brakes Squeak more due to uneven friction surfaces. It’s a good idea to inspect your pads at each oil change or tire rotation. If the pads are low, budget to replace them before they become metal on metal.

When replacing pads, always change them in matched pairs per axle. Mixing new and old pads can cause vibration issues. Also make sure to clean and lubricate the slide pins, backs of the pads, and other caliper hardware. Even minor dirt or rust in these contact areas can create friction leading to squeaks.

Rotor Warping

2020 GMC 2500 Brakes Squeak

As the brake pads wear against the rotors thousands of times over their lifespan, it’s easy for the rotors to develop slight warps or thickness variations too. Some minor warping is normal and won’t cause issues. But larger warps cause tiny vibrations in the brake components that translate into audible 2020 GMC 2500 Brakes Squeak.

You might notice brake squeaks come and go depending on weather conditions or only occur under heavy braking. Warm rotors with even thickness all around don’t squeak, but cooled rotors with high and low spots do. Over time, heavy braking can also cause excessive wear on one side of the rotor creating thicker and thinner areas that rub unevenly.

To test for excessively warped rotors, place a straight edge like a ruler across the face of the rotor and check for gaps. Look for ridges or grooves cut into the friction surface too. Manufacturers specify maximum allowable rotor thickness variations and groove depths. Once past these specifications, resurfacing or full replacement is recommended. Resurfacing brings the rotor back to within spec, while swapping in new rotors eliminates any existing damage or warping.

Proper Bedding Process

2020 GMC 2500 Brakes Squeak

A lot of brake noise on a new or freshly serviced 2020 GMC 2500 may actually be from the pads lightly “screeching” as they properly seat to the rotors through the bedding process. New pad material is glazed and slick to reduce brake dust. It needs to be gradually abraded, or skimmed off through controlled stops to fully integrate the pad friction surfaces with the rotor.

The typical bedding process consists of a series of 20 hard braking sessions from 40-20 mph, allowing the brakes to fully cool in between. This raises the pad and rotor temperatures incrementally to burnish off the glazing. By the last few stops, healthy blue or gray pad material should be visible. Skipping this vital step can lead to noisy, grabby brakes that also accelerate pad and rotor wear. Properly bedded brakes provide a smooth, quiet pedal feel and extend component life.

Grease and Debris Intrusion

2020 GMC 2500 Brakes Squeak

Over time, airborne dust, road grime, water spray, and airborne contaminants inevitably penetrate brake assemblies. Left unchecked, this crud builds up and cakes onto critical sliding surfaces like caliper pins, retainers, and slide surfaces.

Even a minor film of gunk impedes free caliper movement, introducing binding friction to create high pitches squeals. Intermittent noises that come and go depending on weather further point the finger at contamination issues.

The solution is to regularly disassemble brake components as feasible to wipe down, clean, and inspect for buildup. Brake cleaner does an excellent job of cutting through deposits with its solvent action. Make sure to flush all areas like caliper bores and use compressed air to fully dry places that collected moisture. Applying a thin even layer of high temperature rated silicone grease helps protect bare metal and encourage smooth operation.

Always replace any worn, pitted, or corroded hardware too that provides key sliding interfaces. Locking clip retaining pins in position should still rotate freely with light lubrication. These simple cleaning procedures can resolve many aggravating brake squeaks.

Caliper Servicing

2020 GMC 2500 Brakes Squeak

One potential brake noise culprit hiding behind the wheels is worn out or seized calipers. Over time, caliper slide pins corrode in place rendering them immovable. With the caliper locked up, pad material drags and catches unevenly across the rotor face generating that nails on chalkboard 2020 GMC 2500 Brakes Squeak.

Cylinder bores also slowly deteriorate allowing piston seals to leak brake fluid, sticking the pistons partly extended. The caliper cannot evenly and fully return under non-braking conditions. Test for a seized caliper by carefully prying back one pad while someone assists applying the brakes. A stuck piston won’t allow pad retraction under pressure.

When caliper servicing is needed, have the slides, seals, and related components rebuilt or install a new remanufactured caliper. Proper lubrication becomes even more important with fresh internals to ensure smooth, quiet operation. Preventative maintenance like periodic fluid flushes also keeps the cylinders from corroding prematurely.

Final Thought

I hope exploring these technical details provides helpful insights into diagnosing and resolving those annoying 2020 GMC 2500 brakes squeaks. Taking the time for regular inspections and addressing issues early pays off in safe, quiet braking performance for many miles to come. Feel free to reach out if you have any other brake questions!


Why do my brakes only squeak when it’s wet outside?

Moisture is one of the biggest enemies of brake systems. When water hits brakes that are already contaminated with dirt, grime or corrosion, it helps “lubricate” problem areas and worsens existing friction issues. Drying out contaminated brakes often makes squeaks go away temporarily.

The squeak moves around – front to back, does that mean something is worn unevenly?

Not necessarily. Squeaks can behaviorally change as the brakes heat up and cool down due to warping rotor surfaces expanding and contracting at different rates. The true indication of uneven wear is thickness variations that develop over time when measured with a micrometer.

My brake pads are low but not metal on metal yet, will replacing just one Axle’s pads fix the noise?

Mixing new and old pads almost never fully eliminates squeaks on its own. Both sides should be replaced as a set to ensure balanced friction material wear for smoothest operation. Swapping one at a time may cause undesirable vibration.

Why can’t brake shops just resurface the rotors instead of making me buy new ones?

Rotor repair has limitations. Extreme warping, cracking, heat checks or excessive thinning in spots means replacement is necessary. Re-cutting can only remove a maximum thickness of 0.010″-0.030″ before structural integrity is compromised.

What’s the best lubricant to use on caliper slide pins?

For ultimate lubrication and protection against rust and debris, I recommend a high temperature synthetic brake grease. It forms a durable barrier yet remains flexible for smooth movement, unlike typical greases that can melt or stiffen with heat.

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