Proper brake maintenance begins with regular inspection. Better to find problems before they find you.
So what causes the brakes to bind? The most common reasons brakes bind, include:
- Binding caliper pins
- Caliper piston frozen
- Excessive brake component corrosion
- Parking brake cable binding (rear brakes)
- Damaged brake shoes (rear brakes)
- Overfull brake fluid
- Bad brake hose
Binding brakes are common and it’s usually related to corrosion, but as you can see from the above list, they can bind for a ton of other reasons too.
Binding brakes is usually a simple repair and there’s every chance you’ll be able to DIY fix this problem right now. We’ll deal with each possibility in order of how common it is, make sense? But first, let’s do a basic brake check.
Warning, some cars are fitted with dynamic braking systems, these systems can be dangerous to work on without disabling them first. Check if your car is fitted with a brake assist system.
Basic Brake Check
These tests won’t take long or require any tools of any kind, just our senses. They’ll likely give us some clues as to what exactly’s going on.
Check your dashboard for the ABS light, it should come on with the ignition switch and go out when the engine is running. If the ABS light remains on, you’ll need to scan the controller for fault codes.
The first inspection is a visual of the wheels. Very often the wheel that’s binding will have a lot of extra brake dust on the wheel rim. After driving, place your hand on each wheel rim, a wheel that’s binding will be noticeably hotter than the rest.
Pop the hood and check the brake fluid reservoir level, Yikes! Pretty grim-looking fluid here. A reading anywhere between the high and low mark is OK. Sometimes the reservoir can be difficult to read, I shine an LED light on the side of the reservoir which helps.
If the brake fluid level is overfull, you may have found your problem. Brake fluid expands as it heats and will push the caliper pistons out.
If the fluid is very low, it’s a sign the brake pads or shoes are worn or you have a fluid leak. A leak is less likely as your brake pedal would feel noticeably soft.
Most cars and trucks today have wide spoked wheels, which is great for inspecting brake pads and calipers. It’s not foolproof as the inboard brake pad will be hidden and many vehicles are prone to excessive inboard pad wear.
So if the outer pad is low, you can bet the inner is very close to steel on steel. While you’re inspecting the pads, check out the general condition of the rotors and brake calipers, some rust is normal, but heavy corrosion is a sign you need a brake overhaul.
How does the brake pedal feel, soft, hard, or just like normal? If it’s going to the floor, it suggests air in the system or contaminated brake fluid. Now start the vehicle, if the brake booster is OK the pedal should drop slightly.
Shut the vehicle off and have a helper press the brake pedal, can you hear any creaking noise from the brake calipers, walk around all four wheels. Creaking calipers is a sign of a seized caliper or frozen caliper pins.
Finally, have the helper apply the parking brake, any creaking from the rear wheels will need further investigation. The parking brake usually pulls out about three to four clicks on, less than this and it’s too tight.
You may find the brake resources page useful, it’s a fluff-free guide to DIY brake repairs.
Before working on your car’s braking system, be sure it’s safe to do so. Some modern cars will be equipped with auto braking meaning they have a pre-charge. It’s a store of braking energy used for emergency stops. This system needs to be depressurized before opening brake lines or removing calipers.
Integral ABS systems likewise hold a charge, you’ll recognize this type of system as the ABS pump accumulator and master cylinder are all in one. Some modern cars will have an electronic parking brake, this system will need to be placed in service mode before attempting a repair.
Some cars will run drum brakes on the rear but most will have rotors and calipers all around. Rear caliper pistons will likely be screw type, which means you can’t treat them like the front, they need to be screwed and pressed simultaneously. A special brake caliper tool makes life a lot easier.
Binding Floating Caliper Pins
Floating calipers are the most common type of brake hardware setup. The caliper is free to move over and back on smooth lubricated pins as the brake pedal is applied. Trouble starts when one or both of the pins get dry, the caliper then moves across the pins unevenly, which can cause the brake caliper to stick on.
So how do I test it?
Easy, using a flat screwdriver, prise the piston back into the caliper about an inch. Now you have some room to work with, use your hands to pull and push the caliper across the pins. If you can’t move them or they’re tight, they need cleaning.
If on the other hand, you can’t get the piston to move at all, suspect a frozen caliper piston, more on that below.
It’s usually a simple problem to solve, remove the pins, clean them using fine sandpaper, and lubricate them using Silicone grease, re-assemble and you’re good. We use Silicone grease because the pins rubber seals, and petroleum-based grease don’t mix, it will cause the rubber seals to swell.
When the weather pin seals are damaged or worn, moisture and dirt get in, which usually means trouble in the form of corrosion. In plenty of cases, I’ve had to go ahead and change the caliper, pins, pads, and carrier.
Caliper Piston Frozen
This is the next most common reason for binding brakes, it’s pretty easy to test and you won’t need special tools.
Testing the caliper
So you tried to move the piston with the flat screwdriver and it just won’t move. It’s likely the piston is the problem, but to be sure we’ll need to open the bleed nipple.
Now, you need to know, if we open the bleed nipple, you’ll have to bleed the brakes afterward. The car won’t be usable until we bleed the brakes. This isn’t a big job, but you’ll need a hosepipe, a bottle, and the correct brake fluid type.
Open the bleed nipple and try moving the piston back as before. If it won’t budge and only a trickle of fluid runs from the nipple, you can be sure the piston is frozen in the caliper. The only fix here is to replace the caliper.
A frozen caliper is caused by rust on the piston, and the rust is caused by moisture in the brake fluid. (More on brake fluid below) It’s common practice to replace brake components in pairs, replacing just one caliper can cause a brake imbalance.
If on the other hand, the piston does move back, and fluid squirts freely from the bleed nipple. Then it’s more likely the brake hose has broken down internally, causing it to act as a one-way valve. The solution is to replace all brake hoses.
Excessive Brake Component Rust
Corrosion is common, there’s no escaping it, that’s why regular brake inspections will help you prevent major brake problems.
When rust builds upon the carrier and pads, it causes them to bind. Basically, the pads are wedged into the rotor and they can’t move back. As the pad is making contact with the rotor all the time, heat builds expanding the metal, and the problem snowballs.
If the problem is ignored, it can cause rotor, wheel bearing, ABS sensor, and ball joints to fail.
Repairing brake carrier corrosion is an easy fix, you’ll need a wire brush, sandpaper, Copper, Moly, or Graphite dry grease, and a new set of brake pads.
Rotor corrosion can cause the brakes to stick and sticking brakes causes heat which as you know compounds the problem. Heavily corroded rotors happen more commonly to cars that don’t drive very far, or very often, or brakes that are only lightly applied. Under normal driving conditions, braking cleans the rotors and prevents pitting and corrosion.
A quick fix for this condition sometimes works – try braking more vigorously, it helps clean the rotors. If this fails, replace the rotors and pads. If you need brake system parts, check out the Amazon link below.Amazon Vehicle Brake System Parts
Parking Brake Binding
All cars run the parking brake to just the rear wheels and as you know, some vehicles have calipers at the rear and others will have drum brakes. The parking brake on most cars is still operated by pulling a lever that pulls a cable that applies the rear brakes.
The park brake cables often corrode internally, which can cause them to partially stick in the on position. The fix here is to replace the cables.
A park brake cable that’s been adjusted too tightly, will cause the rear brakes to bind. This usually only happens when the brakes warm up. The fix is to back off the park brake adjuster, usually found at the hand brake lever.
Calipers’ rear brakes, commonly have a cable-operated lever. The lever on the caliper will often stick either in the on or off position. This happens a lot with car owners that don’t use their parking very often.
A possible fix here is to clean the caliper lever with a wire brush and use WD40 to try and free it. This can be attempted with the caliper in place. If that fails, replace both calipers. Other cars will run drum brakes, more on that below.
Damaged Rear Brake Shoes
Less expensive cars are fitted with drum brakes, they’re pretty dependable but have many moving parts. Clips, springs, and shoe linings can come loose and get caught in the drum, causing the hub to bind or lock. A leaking wheel cylinder will cause binding too.
The fix here is a complete rear brake job.
Replacing front pads on a car is straightforward, replacing brake shoes is more of a challenge. Certainly having some specialized tools will make this job easier.
Brake Fluid, What You Need To Know
Brake fluid must be the fluid most commonly ignored, coolant, oil, even window washer fluid gets checked regularly. But like all car fluids, if it’s ignored, it will cause damage. The first thing to know about most brake fluid – it absorbs moisture from the atmosphere (Hygroscopic). This causes two problems for the brake system.
1 – It causes the brakes to feel spongy, this happens when the fluid heats and the moisture in the fluid turns to steam.
2 – The moisture in the fluid causes corrosion in the brake lines, calipers, wheel cylinders, master cylinder, and possibly the ABS modulator. All expensive kit.
Fluid types are important, they are graded and market Dot 3, 4, 5, or 5.1. Dot stands for Dept Of Transport.
Brake fluid is either Glycol or Silicone-based, and they can’t be mixed. The Glycol-based fluids Dot 3, 4, and 5.1 are compatible, but shouldn’t be mixed, it won’t hurt any components if you do.
What’s the difference between Dot 3, 4, and 5.1? Basically, the amount of heat they can withstand before boiling, higher is better.
Don’t mix DOT 5
Silicone-based Dot 5 must not be mixed with any of the others, doing so will cause the fluids to react with each other and runs a real risk of damaging the whole braking system.
Dot 5 is used in all military vehicles, and since it doesn’t absorb moisture, it doesn’t need to be changed at regular intervals. It’s excellent in colder climates as the low moisture content prevents freezing fluids and it’s paintwork friendly.
The Glycol fluids Dot 3, 4, and 5.1 will need to be changed every three years. The type of fluid your can takes will be marked clearly on the reservoir cap.
Paintwork damage risk
Before removing the reservoir cap, I always clean it, it’s also important to note Glycol based fluids will strip paint so careful splashing this stuff around.
As you know, overfilling the brake fluid reservoir can cause the brakes to drag. A simple fix is to remove the excess fluid, anywhere between min and max is OK.
Bad Brake Hose
This sounds like a one in million type failure, but it’s a lot more common than that. The brake hose from the caliper to the steel or copper brake lines breaks down inside. Small strips of rubber partly detached act like a one-way valve.
The fluid can get to the caliper, but can’t get back, you’ll experience it as a dragging brake. How do you test it? As with the frozen piston above, after you identify the dragging wheel, go ahead push in the caliper piston, if it will only move when you open the bleed nipple, it’s a faulty brake hose.
The fix is simple, replace the brake line.
Tools And Supplies Needed
Can you drive with seized brakes? No, driving with seized brakes is dangerous. The dragging wheel could lock up at highway speeds, causing injury and further damage to the brake system.
Can bad brakes affect acceleration? Yes, if the brakes are sticking on, the car’s acceleration will feel sluggish. Dragging brakes are dangerous and bad for the engine and transmission.
- About the Author
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.