Brake pedal has very little resistance

My car was making squealing noises, and at the workshop they told me it was the brakes, so I cleaned the brake pads. I accidentally loosened the main line for the brake fluid and some brake fluid drained out. When I was finished I drove to the workshop to buy some brake fluid. The brakes are working but not very optimally, there is hardly any resistance when I step on the brake pedal, and can quite easily push it all the way down to the floor. I topped up the brake fluid and thought that this would fix the problem, yet the brakes were the same on the ride home, very little resistance. What can
Experienced mechanics share their insights in answering this question :
From what you’ve described, I’d advise you to not drive the vehicle and get the brakes bled out. It’s possible that you still have a brake fluid leak in this case.

I’d suggest having this looked at by a certified technician, like one from YourMechanic, who can diagnose your brake system firsthand and bleed your brake system if necessary. Best of luck.

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Air in the brake line(s) is the most common cause of a soft/spongy brake pedal. If air gets into the brake lines, it can prevent brake fluid from flowing properly, causing the brake pedal to feel spongy or soft. If the brakes are soft or spongy, this is a good time to change or flush the brake fluid.
In most cases, stiff brakes are caused by problems with the brake booster. Brake boosters multiply the force applied to your brake pedal, and they work in tandem with the hydraulic fluid in the brake lines. This system, also known as power brakes, allows you to stop a two-ton vehicle with just your foot!
One common reason is a buildup of air in the brake lines, which usually means your vehicle`s brake fluid needs to be flushed. A lack of brake fluid due to a leak (often caused by rust) can also result in an unresponsive brake pedal.
Vacuum – or really lack of vacuum pressure – is the most common cause of a hard brake pedal, and therefore the first thing to look at when a hard pedal is present. Any brake booster (whether from Master Power or any other supplier) needs a vacuum source to operate.
1) Line pressure can only be increased by either increasing the mechanical pedal ratio or by decreasing the master cylinder diameter. In either case the pedal travel will be increased. 2) Clamping force can only be increased either by increasing the line pressure or by increasing the diameter of the caliper piston(s).
However, you can make the spongy brake pedal more sensitive by taking the air out from the brake system. This process is also referred to as `bleeding air`. Bleeding car brakes is essential as it increases the efficiency of the brake system.
Brake pedals should always feel firm when you press down. If your pedals ever feel soft and spongy, you should immediately get your vehicle inspected, as a spongy brake pedal is a symptom of failed braking components in the car.
When your ABS system malfunctions are can also cause a spongy brake pedal. Your ABS system is designed to allow the driver to maintain more control of the car in a high-speed stop.
Pull the brake lever to check the tightness of your brakes

If the lever touches the handlebars, the brake cable is too loose. If you can barely squeeze it at all, the cable is too tight. Ideally, the brake lever should squeeze 1 to 1.5 inches before becoming difficult.

There is some mechanical linkage between the brake pedal and the master brake cylinder. Usually when you want to adjust brake pedal free play it is adjusted somewhere in this mechanical linkage. Very often you might see an adjustable end where the linkage (valve rod) attaches to the master brake cylinder.
Can I Do Anything to Change my Gas and Brake Pedal Sensitivity? Unless you`re a trained mechanic, there isn`t anything you can do yourself to change your pedal sensitivity.
Brake pedals should always feel firm when you press down. If your pedals ever feel soft and spongy, you should immediately get your vehicle inspected, as a spongy brake pedal is a symptom of failed braking components in the car.
Brake pedals should offer moderate resistance when pressed. If your brake pedal is going to the floor with no resistance, there is a problem. The pedal could be failing, or the problem could be as simple as a lack of brake fluid.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Supportive bar attached to brake pedal interrupts proper braking process
ANSWER : It’s possible to have someone alter the brake pedal or adapt a brake pedal from a different vehicle. You may call around to some customization shops to see if anyone is interested in taking on the project. But first, I would try reaching out to the selling dealer with your concern – especially since it is a new model. Good luck.

Brake pedal has very little resistance
ANSWER : From what you’ve described, I’d advise you to not drive the vehicle and get the brakes bled out. It’s possible that you still have a brake fluid leak in this case.

I’d suggest having this looked at by a certified technician, like one from YourMechanic, who can diagnose your brake system firsthand and bleed your brake system if necessary. Best of luck.

Brake sensor is to sensitive causing brakes to flicker while driving. 2005 Mercury Montego
ANSWER : Hi there – your brake light switch needs a minor adjustment. It is adjusted too "tight" or close to the brake pedal lever, or possibly has failed. Adjusting/replacing it will eliminate this flickering problem. I recommend a brake light isn’t working inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

Low brake pedal and anti-lock brakes are not kicking in.
ANSWER : The brake pedal is working to stop the vehicle, but there may be air in the controller unit causing the ABS brakes to not function. I recommend bleeding the brake system from the farthest location from the master cylinder to the master cylinder including the ABS unit. If the brakes are still spongy after a full bleed, then the controller will need to be replaced. If you need further assistance with your brake pedal being spongy, then seek out a professional, such as one from Your Mechanic, to help you.

Hard brake pedal and rear brakes locking up.
ANSWER : Hi. I will help you with this issue you are having with your 2001 Durango. Unless you bled the master cylinder, it is possible there is still air in the system. If you car is equipped with ABS, air could have also gotten trapped in the ABS modulator. If ABS equipped, a bi-directional scan tool would be essential to manually activate the ABS system to clear air from that segment of the lines while you are bleeding the system. It is also possible that in all of this work somehow the proportioning valve has been affected causing the desired pressure differential, front versus back, to get out of spec. Using a 2,500 PSI gauge, you can check the pressures at each wheel and that will definitely give you a clue as to which brake circuit is the issue (or both), whether the proportioning valve is working properly and whether the line pressures at each wheel are within spec. Should you need a second opinion, by all means feel free to contact YourMechanic for assistance and we will diagnose and repair the issue for you.

EPC light on 2004 Jetta. Code said brake switch faulty, but brakes lights worked. Replaced brake switch, now no brake lights.
ANSWER : Hi there. The first thing that pops in my mind beyond of what you have listed is perhaps the electrical harness attached to the brake switch. Perhaps the harness itself is damaged or you have an exposed wire, loose ground wire somewhere. You might want to have a professional mobile mechanic come to your location and complete a brake lights not working inspection to help you diagnose this issue.

When I put my foot on the brake my back left brake light goes off, when I take it off the brake the brake light comes on
ANSWER : I would suggest trying to disconnect and reconnect the wiring to the rear lights. I have seen these older Toyota vehicles rear lighting short out on the lights themselves due to the way the light circuit was made on the lamp housing. Look at the housing circuit on the light to see if one is touching another, and that could tell you why it is malfunctioning. There could also be a problem with the brake light switch. If you are not comfortable dealing with wires, I recommend getting in touch with a certified mechanic who can look at your brake light issue for you to see what’s going on.

Why is my brake pedal going all the way down to the floor?
ANSWER : If you are having to refill the brake fluid from it getting low and the brakes go to the floor means you have a leak in the brake system somewhere. You may have a broken brake line, leaking wheel cylinder or caliper. You should not drive the vehicle until the brake system is inspected and repaired from the leak.