What is the first step in bleeding brakes on a vehicle?

The first step in bleeding brakes on a vehicle is to check the master cylinder fluid level. This is essential because the brake system needs to have an adequate level of brake fluid to function properly before attempting to bleed the brakes. If the fluid level is low, air can be introduced into the system while bleeding, leading to ineffective braking and the need for additional bleeding procedures.

By ensuring that the master cylinder contains enough fluid, you prevent the possibility of introducing air, which can cause spongy brakes and decreased braking efficiency. This preparatory step sets the stage for a successful brake bleeding procedure since starting with an empty or low master cylinder would compromise the effectiveness of the entire process.

The other actions, like checking the parking brake adjustment or starting with the wheel farthest from the master cylinder, are important in their own right but should come after confirming the master cylinder fluid level is sufficient. Pumping the brakes with the engine running is also part of brake maintenance, but it is not the first priority when attempting to bleed the brakes.