Your vehicle’s brake booster provides power assistance during braking. Traditional brake boosters are vacuum operated. However, this design does not work on diesel engines that do not create manifold vacuum. In cases like this, a hydraulic brake booster, or hydro-boost unit, is used.

在水力增强系统中，使用动力转向流体压力代替发动机真空。水力增强式制动助力器包含一个阀，该阀调节施加制动器时的泵压力。内部有一个杠杆，可以控制阀的位置和一个向主缸向主缸施加压力的增压活塞。

更换本单元是一项重要的工作，但是如果您遵循本步骤指南，则可以做到。

第2部分，共2部分：卸下旧的水力增强单元

为了安全有效地更换水力增强单元，您将需要一些基本工具。

Materials Needed

• 杰克
• 杰克站着
• 火炬螺母扳手
• 漏斗
• 动力转向液
• Protective gloves
• 带有扩展的棘轮
• 维修手册（可选）；您可以从Chilton, orAutozone免费提供某些品牌和模型
• Safety glasses
• 小螺丝刀或拾音器

步骤1：找到水力增强单元。可以找到将水力提升单元安装在驾驶员侧的防火墙上。

步骤2：断开负电池电缆。To cut power to the vehicle, disconnect the negative battery cable and set it aside.

Step 3: Remove the pressure from the accumulator。在维修系统之前，请通过关闭发动机泵送制动踏板，从累加器中消除压力，直到您感觉到踏板的硬度不会改变。

步骤4：从水力增强单元中卸下主缸。从水力增强单元中解开主缸。在大多数汽车上，刹车线足够长，可以从助推器中卸下主缸而不会断开线路连接。

步骤5：断开液压线。Disconnect the hydraulic lines using a flare nut wrench to avoid rounding off the fittings.

步骤6：断开推杆与制动踏板的连接。通过卸下固定夹，从破折号下的制动踏板上卸下制动器助推器。

You can remove the clip using a small screwdriver or pick.

Step 7: Remove the hydro-boost unit fasteners。Remove the nuts or bolts securing the booster to the bulkhead. These are usually located under the dash, and you may need a ratchet with an extension to access it.

Step 8: Remove the old hydro-boost unit。Once the fasteners have been removed, you can take the old booster unit out.

Part 2 of 2: Installing the new hydro-boost unit

步骤1：定位新的水力增强单元。Put the new unit in place of the old unit and orient it the same way.

Step 2: Reinstall the fasteners。重新安装水力增强单元紧固件并将其拧紧。

步骤3：将推杆重新连接到制动踏板。将推杆重新连接到制动踏板上，然后将固定夹重新连接。

步骤4：重新连接液压线。Reconnect the hydraulic lines and tighten them down using a flare nut wrench.

Step 5: Reinstall the master cylinder。Reinstall the master cylinder and tighten down the mounting bolts.

Step 6: Top off the power steering fluid。使用适当的车辆和漏斗的液体，将其添加到动力转向箱中，以将其顶上。

步骤7：刹车。Start the vehicle and pump the brakes several times.

步骤8：筹集并固定车辆。杰克up the vehicle and support it with jack stands.

Step 9: Bleed the system。Bleed the system by pumping the brakes and turning the steering wheel until both power steering and power brakes return.

Step 10: Lower the vehicle。杰克up the vehicle, remove the jack stands, and then lower the vehicle to the ground.

步骤11：检查动力转向液。检查动力转向液，然后根据需要再次将其重新涂上。

步骤12：重新连接负电池电缆。重新连接负电池电缆并将其拧紧。

Replacing a hydro-boost unit is a big job. If this seems like something you’d rather leave to a professional, you can alwaysAsk a Mechanic要从Mymechanic的一位认证技术人员那里获得快速，详细的建议。万博体育入口