Jump to content

  • Welcome to Auto Parts Forum

    Whether you are a veteran automotive parts guru or just someone looking for some quick auto parts advice, register today and start a new topic in our forum. Registration is free and you can even sign up with social network platforms such as Facebook, X, and LinkedIn. 

     

What Is Brake Lockup and How to Fix It


Recommended Posts

While automobile brakes are meant to stop a car, sometimes they can do their job a little too well. Thanks to hydraulic pressure and

link hidden, please login to view
muscle, it is quite possible to completely stop a wheel from turning while the vehicle is still in motion. When this happens, it is called brake lockup and it is not a welcome situation. Let’s look at what causes brakes to lock up and how to fix the problem.

What Does Brakes Locking Up Mean?
link hidden, please login to view

Brake lockup happens when the grip of the brake friction material overcomes the grip of the tire on the road. It can happen on dry pavement during a panic stop or on an icy road with just a touch of the brake pedal. Power brakes make it easier to lock up due to reduced pedal effort, but it can happen with manual brakes as well. It can also mean a situation where the brake mechanism fails to release its grip on the wheel, such as a stuck trailer brake.

Why Is Brake Lockup Bad?

A wheel that isn’t turning also isn’t controlling the travel direction of the vehicle. If this happens to a front wheel, it can no longer steer the vehicle.

Brake lockup can also damage your tires. If the vehicle is still moving while the tire is locked up, the road will cause a flat spot on the tire where the tread is worn down far more than the rest of the tire. This can throw off the tire balance, as well as cause erratic handling.

What Causes Brakes to Lock Up?

Let’s take a look at a few common causes of brake lockup.

Sticking Brake Caliper or Wheel Cylinder

If a

link hidden, please login to view
or wheel cylinder isn’t retracting correctly after brake pressure is let off, then it can stick in place. This causes the
link hidden, please login to view
to hold in place against the drum or rotor. Corrosion around the brake caliper or wheel cylinder pistons can prevent them from moving freely. Damage to the piston bores can also cause the pistons to stick in their travel. The solution is to rebuild or replace the brake caliper or wheel cylinder.

Corrosion

If your car brakes locked up and now won’t move, you probably have severe rust affecting the braking components. Drum brakes can’t retract the shoes if all the parts are unable to move freely. This is less likely to happen with disc brakes, but in severe circumstances a brake rotor can rust badly enough to prevent it from passing through the brake pads. This is rare and usually only happens to vehicles that were parked for an excessive amount of time.

Non-Functioning ABS Unit

Almost every modern vehicle is equipped with an anti-lock brake system from the factory. So, what do anti-lock brakes do? Simply put, they prevent the wheels from locking up during braking. The anti-lock brakes unit is usually connected to the brake master cylinder. The

link hidden, please login to view
is a complicated component made up of a pump, valves and a control module. If any of these components malfunction, the overall unit will not operate correctly.

A problem with the anti-locking brake system unit will almost always trigger the anti-lock brake system warning light on the dashboard. If the ABS light comes on, understand that your anti-lock brakes are probably no longer working and need checked immediately. You should never ignore an ABS problem.

Worn Tires

This seems obvious, but too many drivers ignore their tires as long as they are holding air. Take the time to

link hidden, please login to view
. If the tread depth on a tire is less than 2/32”, the tire is worn out and needs replaced. A bald tire can’t grip a wet or icy road, making brake lockup a likely possibility. 

Tires also wear out due to age. Check the tire

link hidden, please login to view
. If the tire is more than six years old, it is no longer able to perform at its peak. Rubber gets hard and cracks as it ages, which reduces its ability to grip the roads and thus in turn can lock up your brakes.

How to Stop Brake Lockup

The key to preventing your brakes locking up when driving is good maintenance. There’s more to maintaining your brake system than just replacing worn brake pads and shoes. Each braking assembly needs inspected on a routine basis along with getting cleaned and lubricated where necessary. Tires need inspected and replaced as necessary. Ask your

link hidden, please login to view
for a brake inspection to make sure your vehicle is in top braking shape.

A Brake Lockup Exception

There is actually one scenario where brake locking is done on purpose. For those who drag race, there is a point where it is necessary to spin the drive tires while holding the entire vehicle in place. This is done using a

link hidden, please login to view
that allows for one pair of wheels to stop. The driver steps hard on the brakes, activating the line lock to hold brake pressure on the desired wheels, then lets off the brake pedal to allow the driven wheel to turn for a burnout. Once the burnout is over, the brake locks are deactivated and the brakes work as normal.

Check out all the

link hidden, please login to view
available on
link hidden, please login to view
or trust one of our 17,000
link hidden, please login to view
for routine maintenance and repairs. For more information on figuring out why your car brakes locked up, chat with a knowledgeable expert at your
link hidden, please login to view
.

Photo courtesy of

link hidden, please login to view
.

The post

link hidden, please login to view
appeared first on
link hidden, please login to view
.

link hidden, please login to view

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By OReilly Auto Parts
      Which Brake Pads Are Right For My Vehicle? | Brake Pad Selection
    • By Dorman Products
      Brake Booster Valve | ASE Test Practice Question 2
    • By Kozmo Jr.
      I tough truck at my local county fair, and I recently bought a 1998 F-150 to run for the event this year. The truck has been sitting for some time and needs new calipers, however I like to build these without having to throw a bunch of money in. I was wondering if there was any way for me to take the calipers off my 2002 Chevy Astro van that I ran last year and put them onto my '98 f-150. I'm assuming I would have to make a custom mounting plate of some sort? I would like an external opinion before I dive into this if you have any input.  
    • By Dorman Products
      Brake Rotor Thickness Variation | ASE Test Practice Question 1
    • A-premium Auto Parts:5% OFF with Code GM5.
    • By Counterman
      Ask anyone what a “complete” brake job is and you’re likely to get a variety of answers. In the context of professional automotive repair, I define complete as meaning correctly done.
      Why? Because the actual work that needs done to any given vehicle can vary depending on vehicle mileage, age and condition. And it can vary based on the equipment. For example, do you have access to a brake lathe? As a counter professional, you’ll have to dig into the details with your customer to determine what they need. However, there are simple guidelines to follow that will ensure you’re advising a “complete” brake job every time.
      Brake Fluid, Brake Fluid, Brake Fluid
      Above all, clean brake fluid is my first requirement.
      It’s probably one of the most overlooked vehicle services, and most people don’t think of it as part of a brake job. It’s an afterthought only considered if they’re forced to do it. Anytime I perform brake work, the first part of the inspection is the bleeder screws. They must be able to open. No brake job is complete without flushing the brake fluid.
      There’s no need to get “crazy” with it either when it’s done on a regular basis. A couple small 12-ounce bottles are plenty. Use a clean suction-bulb to remove as much brake fluid as you can from the master-cylinder reservoir, refill it, then flush fluid through until you can fit the contents of both bottles into the reservoir. Start with five strokes at each wheel until you see how much fluid is being forced through, so you equally balance the flushing from front to rear.
      Contaminated brake fluid is corrosive and damaging to all the internal brake-system components, and it can cause poor braking performance. Even though every manufacturer specifies to flush it on a regular basis, it’s still out-of-sight, out-of-mind for a lot of people. In my opinion, you can’t change the brake fluid too often.
      A complete brake job not only includes fluid, but also calipers or wheel cylinders in any situation where the bleeders don’t open.
      Pads and Rotors
      When disc brakes are being serviced, pads and rotors are at the core of the job. It’s far less common to resurface rotors than it has been in past times, and it doesn’t matter if you take that road or go with new. But the bottom line is something must happen with the rotors. “Slapping” a set of pads on old rotors is an immediate fail. The pads will never bed in properly, and you’ll only be faced with poor brake performance, uneven pad wear and unwanted noise.
      The bottom line: Rotors must be resurfaced or replaced for the job to be complete. By the same token, old pads on new rotors equals an incomplete brake job.
      Why would someone do this? Your guess could be as good as mine, but believe me, I’ve seen it all and I’m sure you have too. New pads and rotors bed in together. In other words, they rely on each other for proper brake operation.
      Drum Brakes
      If you thought there were some offenders with disc brakes, drums are often worse. For some reason there seems to be a perception that brake drums miraculously never need service, but the same theories hold true. If you’re replacing brake shoes, the job is only correctly done by resurfacing or replacing the drums.
      Hardware
      Hardware is anything from springs and hold-downs on drum brakes to anti-rattle clips and slide-pin boots on disc brakes. All these little pieces are important to proper brake operation. On drum brakes, even though everything may be intact, it’s also old and the springs will simply be fatigued. On disc brakes, the same holds true and even anti-rattle clips that look OK can be worn or fatigued in some manner. Luckily, most pads come with the hardware. They don’t put it in the box just for fun.
      One of the most overlooked parts of disc-brake service is the fact that the pads must be able to move freely in the caliper bracket and the calipers also must be able to move freely back and forth. Most calipers (excluding fixed calipers) feature slide pins that allow this to happen. No brake job is complete without removing the slide pins, cleaning them up, lubricating them and reinstalling them with new boots when required.
      It’s surprising how often the slide pins are stuck and how often brake pads are jammed in place due to rust, and the rust must be completely removed to allow free movement of the new brake pads. Stuck pins or stuck pads cause uneven and accelerated wear, dragging brakes, pulling and excessive heat buildup.
      Lubrication
      I touched on it already, but it’s worth a second mention. In addition to the slide pins on calipers, the brake pads require lubrication any place they contact the caliper bracket or caliper. Brake lube is specifically formulated to a) not damage or swell rubber components such as piston or slide-pin boots, b) prevent vibrations that cause noise, c) lubricate the pad contact points so they move freely in the caliper bracket and d) resist washing out.
      In the case of drum brakes, the backing plates feature specific contact points for the brake shoes, which should be cleaned and lubricated. Brake shoes also require lubrication at pivot and contact points between the shoes and hardware.
      Inspection
      Determining what is required for a complete brake job can only be done through inspection and disassembly. It’s easy to see worn-out pads and rusty rotors through a wheel, but even when that’s evident, you can’t see anything else until you take things apart. This is when you inspect for brake-fluid leaks, seized or damaged hardware, torn dust boots and functional bleeder screws.
      If leaks are found or dust boots are torn on a caliper piston or wheel cylinder, or if the bleeder won’t open, the components need to be replaced. Only until disassembly is performed during an inspection can you say absolutely what’s needed for any given vehicle. Sure, we can all look at a 50,000-mile four-year-old vehicle and say that it needs pads and rotors, and most likely those are the only hard parts it will need. But it’s no guarantee, and the higher the mileage and older the vehicle, the more likely we’ll find something else, which leads to the next category …
      Recommending Parts
      There’s always a way to work into the conversation of a complete brake job. The next time someone comes in and wants pads and rotors, you might ask, “Would you like me to look up caliper availability just in case a bleeder screw doesn’t open, or a caliper pin is seized?” If they’re an experienced technician, they know how often that happens, and they’ll likely say yes, just to know in case they need them, and they’ll appreciate it!
      If they’re new at all this, it will get them thinking and open the door for your advice. The next thing you know, they might change their mind and decide to buy new calipers – or at minimum they’ll leave with the extra goodies they need for a complete brake job, such as brake lubricant, brake fluid, brake cleaner and some shop rags. If they get into the job and realize there’s a problem, they’ll be right back at your store.
      The post
      link hidden, please login to view appeared first on link hidden, please login to view.
      link hidden, please login to view

×
  • Create New...