How to Change a Hydraulic Cylinder

Many times, a hydraulic cylinder in your car can be repaired by changing out pistons or seals inside the cylinder. However, on rare occasions, you may need to replace the entire cylinder itself. If that situation arises, you will need to know how to correctly remove the old hydraulic cylinder and install a new one. This easy-to-follow how-to guide will show you to do just that.

(Note - In most cases, if you order an entire cylinder assembly from the car manufacturer or other aftermarket parts maker, the cylinder will come with seals and pistons included. Therefore you should not need to disassemble the cylinder.)

Step 1 - Prepare to Work

First, disconnect the negative battery cable from the terminal post on your car's battery.

Step 2 - Jack Up the Vehicle

Jack up your vehicle and place it on jack stands, so that you can work with the hydraulic cylinders on your vehicle.

Step 3 - Remove the Hydraulic Hose

Depending on your vehicle, the hose may be held to the cylinder using clips or clamps. However, in most cases, you'll be able to remove the clamps with a wrench or other tool. Remove the screw from the clamp that holds the clipper clamped in place and disconnect the hose.

Step 4 - Remove the Hydraulic Cylinder

Remove the bolts that hold the hydraulic cylinder in place.

Step 5 - Drain Hydraulic Fluid

Place a plastic bucket or container underneath the cylinder and hoses to catch the hydraulic fluid that may drain out. Then, hold the cylinder upside down in order to drain the remaining fluid into the bucket or plastic container.

Step 6 - Clean the Cylinder Area

Take an old rag or towel and wipe the area where the cylinder was installed to remove any major dirt or grime in the area.

Step 7 - Install New Hydraulic Cylinder

Use the bolts that were used to hold the hydraulic cylinder in place when installing the new cylinder. Be sure to apply a sufficient amount of torque to the bolts to ensure that they won't work loose when the vehicle is being driven.

Step 8 - Re-connect Hydraulic Hose

Connect the hydraulic hose to the cylinder. Then, push the clamp or clip up to the end of the hose so that it can hold the hose in place. Tighten the screw or bolt that locks the clamp or clip.

Step 9 - Fill With Hydraulic Fluid

Locate the fill plug on the master cylinder and remove it or the cover. Fill the master cylinder to the fill line. Replace plug or cover.

Step 10 - Lower the Vehicle

Remove the jack stands and use the car jack to lower the vehicle.