That depends what kind of oil, but most oils will adversely affect the rubber brake seals. I would replace all the brake fluid in your car as soon as possible.
If non brake fluid is added to the master cylinder, possibly.If non brake fluid is added to the master cylinder, possibly.
Open brake fluid reservoir for the brakes - make sure it is full of brake fluid - put lid back on reservoir then pump the brakes then hold the brakes on - have someone open the bleed screw on the brakes and let the air and oil out and close it again quickly and repeat until the air bubbles stop in the brake fluid, also checking to make sure you do not run out of brake fluid before you finish bleeding the brakes.
Your brake fluid is how the brake system converts mechanical force of your foot on the brake pedal, into hydraulic force that applies your brakes. Without fluid, your hydraulic brakes will not function.
Air in the brake system- Brake system needs to be bleed and fluid needs to be added while you are doing that.
In the brakes.
Brake Fluid.
Check the brake fluid reservoir, it may be low on brake fluid indicating it is time to have the brakes inspected.
No but, the brake fluid level will drop as brake pads/linings wear.
Sticking caliber. Flush the brake system and install fresh brake fluid, then bleed the brakes. If that does not help, replace both calibers and brake pads on the axle where the brakes are grabbing.
Siphon it out. Do not drive or pump the brakes. Replace the brake fluid. This will cause the brakes to fail.
this would be brake fluid have it checked before the brakes fail and you wreck
If you replace any brake component that breaks the brake fluid seal or you let it get very low of brake fluid, yes, you must bleed the brakes.