Whenever I apply the brakes it swerves

Hello,

This pull during braking can be caused by seized brake caliper slides, failed brake hose, ball joint wear, loose inner tie rod end, it can also be due to tire core separation.

One of the common reasons is having seized caliper slides. When the caliper slide bolts get stuck or seized the caliper will either not fully engage or release creating a brake pull.
One way to check this is to drive the vehicle (safely) and after using the brake few times, stop and check the temperature of the rotors using an infrared laser temperature reader. If there is a problem, there will be a large temperature difference.

Here is a helpful guide that goes over the typical problems for brake pull:

https://www.2carpros.com/articles/car-pulls-right-or-left-when-driving-or-braking

Please let me know if you have any questions.
Thank you.