I let my uncle change my pads and rotors and now everytime i press the brake all i get is an air sound scared to drive

Just changed brakes and rotors and now all i get is an air sound everytime i step on the brakes

My car has 200000 miles.

Experienced mechanics share their insights in answering this question :
Usually a hissing noise when you hit the brakes involves the vacuum brake booster. But it seems unlikely that working on the brakes should effect this component. Changing brake pads and rotors is a pretty straightforward job, even on a Cayanne. So I find it hard to imagine that your uncle did anything that would make the car unsafe, but then again, I’ve seen some pretty outrageous things over the years so it’s hard to say for sure from this chair. Probably the most common mistake that home mechanics make is not correctly installing all of the hardware, or leaving it off altogether. Sometimes I see the wires for the brake pad wear sensors incorrectly routed, so they get involved with some moving part. More seriously, I’ve encountered brake hoses that were twisted when re-installing the caliper, or caliper retaining bolts that were cross-threaded or not correctly torqued. So in the interest of safety, I suggest you Contact Your mechanic to have a technician come to your home and inspect the brakes on your Porsche to make sure everything is correct. Your Uncle doesn’t even need to know.

How to Identify and Fix Common car Problems ?

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There are a few different reasons why your brakes may still be grinding after you`ve replaced the pads or rotors: It could be as simple as the brake pads need time to settle in. They`re a bit stiff at first and can make noises like grinding or squealing for a little while before they get comfortably worn in.
If new brake pads are put onto a vehicle with damaged rotors, the pad won`t properly contact the rotor surface, reducing the vehicle`s stopping ability. Deep grooves that have developed in a worn rotor will act as a hole-puncher or shredder and damage the pad material as it is pressed against the rotor.
A rubbing sound could be an early sign of a worn brake pad rubbing against the rotor. The pad could be in an early stage of wear before it moves on to a heavy grinding noise. Another possibility is a braking pad that hasn`t fully released. If you haven`t driven your car in a while, there may be rust on the rotors.
If your vehicle brakes are new and still making a squeaking sound, the fix may be as easy as lubricating the touchpoints. Lubricating the brake pads involved taking the brake pads out from the calipers and then spreading the brake lubricant to the back of the brake pad, not the friction material.
It is quite common for new rotors or brake pads to squeak within the first few days before they`re completely broken in. If it has been more than a few days and the squeaking still hasn`t stopped, you should have your brakes looked at by a professional.
The only time you would need to adjust disc brakes on a car is when they have been changed or any time the caliper has been removed.
If you install a curved vane rotor backwards, it won`t be able to pump air as effectively. That means a curved vane rotor installed backwards can`t dissipate heat as well as it should. To install a curved vane rotor correctly, make sure the vanes at the top of the rotor are tilting rearward.
Yes, you will need to bleed your car`s brakes after changing its brake pads. This helps to remove any dirt in the braking system. It`s common for people to open both the bleeder valve and squeeze calipers while changing the brake pads.
If your rotors are faulty, they may produce a squeaking, squealing, or grinding sound when you apply the brakes. Warped rotors usually emit a high-pitched squeak, while severely worn rotors tend to make a scraping noise.
As a general rule, you should get your brake pads replaced every 10,000 to 20,000 miles to keep wear to a minimum. When it comes to your rotors, you have a bit longer. Your rotors should be replaced between 50,000 and 70,000 miles to keep your brakes in peak health.
When brakes are making a scraping sound, it could indicate that a foreign body has gotten lodged between the pad and the rotor. In this case, the object needs to be removed. Similarly, squeaky brakes could simply mean they need some brake pad lube.
Squealing. Squealing or squeaking noises usually indicate that your brake pads require replacement. Some brake pads are equipped with wear indicators in the form of small steel clips, which make a squealing sound when the pad has worn down.
How to identify if my rotor is loose? To check if your rotor is loose, you may begin with basic observation. Give your watch a few shakes and listen to the sound the watch is making. If you hear a scraping sound, which is like a metallic sound that scrapes the case back or movement, your rotor most likely is loose.
No, brake pads are a few mm away from the rotors held by the calippers and come in contact with rotor only when brake pedal is pressed. Ifnits always in contact with the rotor, vehicle will be very hard to move and pads would wear out faster.
Common Causes of Worn Rotors

Panic or emergency braking at high speeds can cause rotor wear. The friction from the brake pad grabbing the rotor can cause high enough heat to result in wear.

Answer: Yes, flushing or changing the brake fluid is legitimate preventive maintenance for your car. We typically recommend a brake fluid flush when we`re already changing brake calipers, pads or rotors.
Each brake must be bled in the correct sequence. Generally, you bleed the brake most distant from the master cylinder first, but some cars require a different order.
If you have an open-spoke wheel design, you can run your finger vertically down the brake rotor friction surface. If you can feel and see noticeable grooves, then it`s time for new brake rotors. For cars with hub caps that don`t expose the rotor, you will need to remove your wheel to inspect your brake rotors.
Rotors are very capable of lasting more than 100,000 miles with proper brake inspections, maintenance, and brake pad changes. When brake rotors are replaced, it`s advised to replace all of them and brake pads at the same time.
Brake pads generally last between 30,000 and 70,000 miles, but some can last as long as 100,000 miles. There are many factors that account for this wide range. First, brake pads come in a variety of types and compositions and are attached to even more varying brake systems and rotors.
Discs or rotors work by pads that clamp down on the rotor to create friction to slow your vehicle. The pads indeed wear out first. The rotor`s primary function is to absorb that friction. The more worn down your rotors are, the less heat they can absorb at one time, which results in longer stopping times.
The noise you are hearing is very likely caused by the brake pads wearing down over time like they are designed to do. You are hearing the metal of the brake calipers rubbing on the metal rotors. This is doing damage to your vehicle, and you will want to have the brake pads changed as soon as possible.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

I let my uncle change my pads and rotors and now everytime i press the brake all i get is an air sound scared to drive
ANSWER : Usually a hissing noise when you hit the brakes involves the vacuum brake booster. But it seems unlikely that working on the brakes should effect this component. Changing brake pads and rotors is a pretty straightforward job, even on a Cayanne. So I find it hard to imagine that your uncle did anything that would make the car unsafe, but then again, I’ve seen some pretty outrageous things over the years so it’s hard to say for sure from this chair. Probably the most common mistake that home mechanics make is not correctly installing all of the hardware, or leaving it off altogether. Sometimes I see the wires for the brake pad wear sensors incorrectly routed, so they get involved with some moving part. More seriously, I’ve encountered brake hoses that were twisted when re-installing the caliper, or caliper retaining bolts that were cross-threaded or not correctly torqued. So in the interest of safety, I suggest you Contact Your mechanic to have a technician come to your home and inspect the brakes on your Porsche to make sure everything is correct. Your Uncle doesn’t even need to know.

Is it normal for the brakes to get hot or smell hot after the pads and rotors are changed on the rear brakes?
ANSWER : Hi, thanks for writing in. I’d be happy to provide my insight.

From the description of your 2010 Pontiac G6 braking issue, there are a few likely causes. If the piston in the caliper did not move freely than this will allow the brake pad to drag on the rotor. When the pad drags it can overheat the rear brakes and cause them to fail. The caliper will need to be inspected before the vehicle is driven more.

If you would like help getting these inspected, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose these brake problems for you, and make or suggest any repairs as needed.

After new brake pads & rotors, SUV has a grinding noise
ANSWER : Hello. It sounds like the brake calipers may be locking up and causing the grinding noise that you are hearing. I would check to see if the caliper hose is twisted. If it is, this may cause the brake fade that you are experiencing. It is also possible that the master cylinder is starting to fail which could also cause the problems you are having. I would suggest that you have a certified technician, like one from YourMechanic, complete an inspection of your brakes and determine if your master cylinder needs to be replaced, or if the brake calipers need to be replaced.

Brakes won’t let go after changeing main brake cylinder.
ANSWER : Rule out obvious causes such as sticking calipers. If you are positive that the caliper pistons are free and the pins in the torque plate are free as well, measure the brake line pressure at each wheel to determine both if the pressures are correct (and proportioning valve is working) and if pressure releases. If pressure is not releasing, see if failure to release is in one or both circuits (the brake system is sectionalized for safety). If the problem is global, the master cylinder is stuck. If this does not resolve it, request a brake system diagnostic – pressure testing and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Front steering/suspension shaking while braking
ANSWER : Hello. It is possible that you could have a control arm bushing that has failed. When a control arm bushing fails and the brakes are applied, the vehicle will display these exact same symptoms that you described. I would recommend enlisting the assistance of a qualified professional to inspect your steering and suspension parts for worn control arm bushings. If any excessive wear is found in the control arm bushings, I would recommend having them replaced as soon as possible because this can result in a safety issue. If you need help getting this taken care of, a certified professional can diagnose the suspension and brake system to verify the problem and move forward with appropriate repairs.

Rear brake job
ANSWER : Hello, thank you for writing in. These situations are understandably questionable. The service providers at a lot of common oil changing and tire repair centers will quote you for a variety of things that can be updated. This does not always mean you are in dire need for more repairs. If braking seems to be harder, spongy, or takes longer, then you have reason to be concerned. Otherwise, you should check the amount of brake pad material left on the calipers. This can be visually inspected without too much trouble. Remove the wheel and physically measure the amount left, compare them to your vehicle specifications. It is a little early to worry about brake fluid or the rotors. However if the brake fluid is low, the rotors are warped from a hard stop, or there are obvious issues you should look into the system further. Only further inspection will confirm or deny the recommendations. For a second inspection, contact our service department to schedule an appointment.

I am advised to change brake pads. Do I also need to get rotors turned?
ANSWER : Hey there. You should have the rotors resurfaced or replaced if cutting them takes the surface below the minimum thickness. If you would like to have the brake pads and rotors repaired for you, a certified technician from YourMechanic can come to your location to have this done.

Uneven brake rotor wear
ANSWER : Hello. I tried to view the pictures but the link seems to be broken. It sounds like you have two different problems reading the description of the problem. The first is the brake pads being too tight and binding in the caliper bracket. This is most likely caused from the pad ends are not machined smooth and do not slide into the caliper bracket smooth. This will cause them to bind and cause low brake application or will keep the brakes partly applied wearing them down quickly. The other possible problem is the caliper may be binding on the slides or the piston is binding. If you would like precise advise on exactly what needs repair, have a certified professional diagnose the brake system in person and follow through with correct repairs.