How to Remove Air Bubbles in a Brake Line With a Mityvac
- 1). Loosen the lug nuts on all four vehicle wheels. Lift the vehicle and lower it onto jack stands placed under the car at all four corners. Remove the lug nuts and the wheels and set the wheels aside.
- 2). Consult your owner's manual for the order in which to bleed the brakes at each corner of the car. Most brake systems are bled starting at the corner farthest from the master cylinder, which is generally on the left side of the engine bay, so the right rear corner would be first, then the left rear corner, the right front corner and finally the left front corner. However, not all cars are bled in this order.
- 3). Locate the caliper at the first corner you are bleeding. The caliper will have a brake line going into it as well as a small bleeder valve that is used to bleed the brakes. Place the appropriate-size clear bleeder hose on the valve. The Mityvac kit comes with a variety of hoses and adapters. Place the other end of the hose on the Mityvac brake fluid reservoir. The reservoir looks like a small cup and has a lid with a clear plastic hose coming from each end.
- 4). Fasten a hose from the Mityvac reservoir to the hand pump. Check the car's brake fluid reservoir to make sure it is full. To do this, open the engine bay, remove the lid for the reservoir and check the level. Fill it with fresh brake fluid if it is low.
- 5). Pour brake fluid into the Mityvan fluid reservoir to the fill line. This is about 2 inches from the bottom of the reservoir. Pump the hand pump a few times before loosening the bleeder valve. Open the bleeder valve with an open-ended wrench a half-turn or just enough that brake fluid comes out.
- 6). Pump the handle on the pump. Brake fluid should start pumping through the clear hose into the Mityvac reservoir. Keep pumping until there are no large air bubbles in the brake fluid. Periodically check the car's brake fluid reservoir in the engine bay to make sure the level has not dropped down enough to allow air to enter the system through the master cylinder. Fill the reservoir up if it is low.
- 7). Loosen the bleeder valve on the caliper and continue bleeding until there are no air bubbles, ensuring that the car's brake fluid reservoir always has sufficient brake fluid. You should also periodically remove brake fluid from the Mityvac reservoir if it becomes too full. Once there are no air bubbles, tighten the bleeder valve with the wrench and pull the hose off of the valve.
- 8). Repeat the above steps for the remaining corners of the car. Bleed all four corners twice. Check the brake pedal by turning the car on and pressing the brakes. A properly bled brake system should have a firm pedal. Reinstall the wheels and lower the car back to the ground.