Sometimes, a car jerks when braking, which can be disconcerting for both the driver and the passengers.
In 2020, more than 38,000 Americans were killed in automobile crashes, so problems with your brakes should make you nervous. You need your car in tip-top shape to keep you safe on the roads.
If a car jerks when braking at low speed, it could be a sign of a mechanical issue. Or, maybe there is just a jerk behind the wheel!
To help figure out what’s going on, let’s look at some common issues and what you can do to help your car brake smoothly.
Start With the Simple Things
Let’s assume that you just felt your car jerk when braking. Suppose that you were approaching a red light, the driver pressed the brake pedal, and instead of a smooth stop, there was an uncomfortable hesitation, jerk, or lurch.
Rule out some things that might not be directly related to the brake system first. Then if the issue is still unexplained and unresolved, you can move on to other possible causes.
If the car has a manual transmission, it may feel a bit jerky when braking, especially with a novice driver working a manual clutch behind the wheel.
If the driver doesn’t shift gears correctly when decelerating and braking, the car may lurch. To downshift properly, a manual transmission driver needs to work the clutch pedal, brake pedal, and the gear shifter in coordination.
If they’re not very good at doing that or still learning how to, that lack of coordination can be the source of a jerk when braking. Check out this video to see how to operate a manual transmission smoothly when braking.
The driver probably just needs more practice working a manual clutch to get a smoother result when braking. Or, the clutch itself may be wearing out.
Sometimes, floor mats can slide out of place and interfere with the operation of the brake pedal. If that happens, the pedal may not go down smoothly when pressed, and the car may jerk as a result.
This issue is an easy one to fix by repositioning the floor mat or carpet. If it is creased, bunched-up, or keeps happening, consider removing it or getting a new one. You might be able to switch it with the mat from the passenger side for a quick fix.
Worn tires lack sufficient tread to maintain a good grip on the road surface. When tires are worn, or their tread has become uneven, the vehicle may jerk a bit, especially if the roads are slick with rain, ice, or snow. Checking your tire wear is easy to do and essential for safety, so make sure to do so before you assume you have a brake problem.
Brake rotors are susceptible to warpage as they get older, especially if they have been turned on a brake lathe in the past. When a rotor shrinks, thermal shock from overheating or rapid cooling can produce a jittering sensation when the brake pedal is pushed.
Your Car Jerks When Braking: Brake Issues
If you have ruled out the most simple stuff that could cause jerking, you pretty likely have an issue with the braking system on your car.
Mechanical Braking Problems
The brakes on a car have a tall work order. They use friction to slow the car down. Modern cars with disc brakes have pads that clamp down on the rotors when the caliper’s pistons are activated in response to the driver pressing the brake pedal.
Older cars have drum brakes, where the process is similar, but the internal brake shoes press outward against the drum lining. Drum brakes are less and less common on passenger vehicles, though some bigger and heavier trucks still have them, especially on the rear axles.
The brake pads or shoes are the most likely suspects when there is a mechanical braking issue. At the end of their life, they need a replacement. If you’re feeling a jerk when braking, you very well might need new pads.
Sometimes, the rotors also become worn down. In some cases, it’s possible to resurface them to get them to help stop the car smoothly. If they are too deteriorated or warped, they need replacement as well.
Brake Power Assist Issues
Braking systems on modern cars almost always use some manner of booster system to assist with powering braking. Most passenger cars use a vacuum brake booster tied to the engine to increase pressure, while heavier trucks use pressure from the vehicle’s power steering system instead.
When working properly, the power assist system makes braking easier on the driver by amplifying their input on the brake pedal to smoothly and safely stop the vehicle.
When these components break down, they can lead to a situation where a car jerks when braking. Then, they need replacement.
The braking system on the vast majority of vehicles relies on a closed hydraulic loop. There is a master cylinder that acts as sort of the heart of the system, responding to the driver’s use of the brake pedal.
The hydraulic fluid in the master cylinder squeezes through the brake lines running to the individual calipers (disc brakes) or cylinders (drum brakes)—sort of like how blood rushes through our blood vessels to our hands and feet.
Hydraulic fluid doesn’t compress under pressure, so the brakes actuate when you press the pedal and force the fluid toward the mechanical braking components.
Sometimes, air can get inside the hydraulic system, causing a spongy feel in the brake pedal. That might lead to a car that jerks when braking.
Bleeding that air from the brakes is a two-person job, so don’t try to do it yourself unless you know what you’re doing and you have a helper at the ready.
Electrical and ABS Problems
Modern cars almost all have some sort of Anti-Lock Braking System (ABS). ABS is an electronic control system that helps prevent your brakes from locking up when you lose traction.
For instance, if you’re sliding on icy pavement and holding the brake pedal down, the ABS will modulate the hydraulic pressure to release and reapply the brakes very quickly. This will help you maintain steering control and still slow the vehicle, and you won’t have to use your foot to pump the pedal.
You might feel a vibration in the brake pedal if this happens to you. Otherwise, the brakes would lock up, the tires would stop spinning, and you would lose steering control.
If your ABS is failing and you’re feeling jerking when braking, you’ll need to take a trip to the mechanic, as it’s fairly complicated to repair.
Car Jerks When Braking Bottom Line
A car that jerks unpredictably when braking is inherently dangerous. You should observe what’s happening carefully and drive very cautiously.
Once you rule out the simple stuff, it’s probably time for a trip to a mechanic if your car jerks while braking.
Why does my car jerk at high speeds?
A vehicle jerking or surging forward at high speed is an indication that it’s not receiving the proper balance of air and fuel. This jerking or bucking may be caused by a variety of components in the fuel or air intake system. Fuel efficiency can be negatively affected if problems with these systems arise.
Why does my car jerk when accelerating and braking?
One of the most frequent reasons for an accelerator to become jerky is dirty fuel injectors. When you try to accelerate while stopped and when you attempt to drive at a constant speed, your vehicle loses power due to a dirty injector. This is caused by an engine misfire.
Does a dirty air filter cause your car to jerk?
A dirty air filter reduces the amount of air delivered to the engine. This might lead to an increase in unburned fuel, which turns into soot residue. Soot may accumulate on the spark plug tips, preventing them from delivering a good spark. The car may jerk, idle erratically, or in some cases, the engine can misfire as a result of this.
Can transmission cause car to jerk?
A car’s automatic transmission uses fluid to change gears. Regular transmissions keep your automobile smooth when you shift. If your automatic transmission shudders, jerks, or shakes while you’re changing gears, the transmission fluid level may be low or the gearbox may need replacing