How to Get to the Firewall Master Cylinder on a Ford F-150

The master cylinder on your Ford F-150 model develops the necessary pressure in the brake system to slow or stop your truck. However, worn or damaged pistons, valves, cups or housing may leak, stop working and make your brake system fail. Luckily, it is possible to remove and install a new unit on your F-150 pickup truck yourself.

Instructions

Removing the Master Cylinder

1

Disconnect the ground, battery cable [the one with the negative sign (-) next to the battery post] using a wrench.

2

Locate the brake master cylinder on your Ford F-150. This is attached to the brake booster, a cylindrical, drum-like component mounted on the driver side of the firewall inside the engine compartment. The cylinder has a plastic reservoir tank mounted on top with an electrical connector on the side.

3

Remove as much brake fluid as possible from the master cylinder reservoir using a hand siphon pump.

4

Unplug the level-switch electrical connector from the side of the master cylinder reservoir.

5

Place one or more shop rags under the master cylinder to catch any brake fluid once you disconnect the brake lines.

6

Disconnect the brake lines from the master cylinder. Use only a tubing or line wrench to prevent damage to the line fittings.

7

Plug or cover the brake line openings and master cylinder ports with plastic bags to prevent contamination of the brake system.

8

Unbolt the master cylinder from the brake booster using a wrench or ratchet and socket.

9




Remove the master cylinder from the engine compartment being careful not to bend or damage the brake lines. If the master cylinder on your F-150 model is fitted with an O-ring body seal between the cylinder body and brake booster, remove and discard it.

Installing the Master Cylinder

10

Transfer the reservoir and the two mounting reservoir seals from the old master cylinder to the new unit, if necessary.

11

Bench bleed the new brake master cylinder according to the instructions included with the new or rebuilt cylinder unit.

12

Set the new master cylinder in place using a new O-ring body seal and start the mounting nuts by hand.

13

Tighten the cylinder mounting nuts using the wrench or ratchet and socket.

14

Connect the brake lines to the master cylinder using the tubing or line wrench. Start the fittings by hand and then tighten the nuts.

15

Plug the level-switch electrical connector to the new master cylinder reservoir.

16

Connect the ground, battery cable using the wrench.

17

Bleed the brake system following the instructions in your vehicle service manual for your particular Ford F-150 model.