Tips for Maintaining a Gear Pump

A car on the road.

A gear pump is a type of positive displacement pump that is used to pump low or high viscosity fluids. The most common application of a gear pump is to pump hydraulic fluid in various types of vehicles. The most common example of a gear pump is the hydraulic gear pump that is used in the transmissions of many vehicles.

Regardless of the type of gear pump you are working with, a few good maintenance tips might be able to save you the considerable expense of having to repair one.

Checking for Signs of Wear and Tear

In order to keep your vehicle in good running condition, you need to perform periodic maintenance and service to the car. Your maintenance should also include the periodic checking and service of the gear pump in your vehicle. You will need to be handy with a screwdriver and a bearing puller in order to properly maintain the gear pump; however, servicing the gear pump yourself can save you a bundle versus having it done at a car repair shop.

When you examine the gear pump in your vehicle, check the teeth in the gears for signs of wear and tear. A brand new gear pump usually ships with a clearance of about 0.005 to 0.007 inches between the teeth of the gears and the chamber wall. This clearance is just enough for a piece of very thin wrapping paper. Therefore, you can use this type of paper to check the clearance between the gear teeth. If the paper slides in and out between the teeth too easily, then the gears have been worn due to scrubbing or poor lubrication.

The Pump Bearings

Another important component of the gear pump is the bearings. You should occasionally check them for signs of wear as well. Good bearings should be completely round, while defective bearings will often appear to be oval, or egg-shaped. Defective bearings allow the gears in the pump to shift position in the chamber, rather than remaining straight and true.

You will need to remove defective bearings by using a bearing puller. The device uses a collet to remove the bearings and you should be able to pick one up at your local automotive tools store. If you are lucky, however, you may be able to remove the entire bearing assembly. It will depend on the make and model of your vehicle and the type of gear pump that is used.

Other Things to Check

Although the bearings and gears are the components most susceptible to damage in a gear pump, there are other areas that you should occasionally check as well. For instance, the pin that holds the gears into their shafts is crucial to the reliable operation of the pump. If the pin becomes sheared or cracked, it could lead to a gear pump that does not function at all. Likewise, you should carefully inspect the pump cover for bulges or cracks that could indicate there are pressure problems in the pump.