Vacuum Pump

What is an automotive vacuum pump and where is it located?

A vacuum pump removes air from a space to create an area with less pressure than the atmosphere outside that space. In the case of the vacuum pumps that we carry here at 1A Auto, they are primarily used in diesel applications. There are some gasoline engines, primarily made by BMW, that use complicated variable-lift intake valves instead of a throttle to control the air flow to the engine, and these will also need a vacuum pump. They are not that common though, and vacuum pumps remain primarily a concern for diesel engines. Vacuum pumps can be found on the front of the engine, like other engine accessories, with hoses running to vacuum operated systems like the power brakes. 

The vacuum created by the pump can be used to drive a number of accessories in your vehicle, including the exhaust gas recirculation valves, locking systems, and heating and A/C vent controls, among others. The most important function of the vacuum pump, though, is to provide vacuum to the power brake system. Brake boosters use vacuum to make a low pressure area to make it easier to push your brakes. Without vacuum, it would be much harder to press your brakes, which would make driving quite a bit more dangerous.

Gasoline engines produce their own vacuum in the intake manifold. A closed or partially closed throttle, which you have any time you’re not running wide-open, restricts air flow into the intake manifold. The pistons, of course, draw in air during the intake stroke. The combination of these two things creates a vacuum in the intake manifold. Vacuum tubes connected to the intake manifold can run systems like the brake booster in a gas engine. Diesel engines, however, don’t use a throttle. Instead, they vary engine speed by changing the fuel injection. Without a throttle there will be zero vacuum generated in the intake manifold, so a separate pump is necessary. 

These pumps use a piston or a rotary vane to create a low pressure area that draws out air, creating the vacuum. The moving parts in the vacuum pump can be driven in one of two ways. The pump could be run by the crankshaft via a belt, like the alternator and other engine accessories are. It could also be run by an electric motor. Pumps of the first type are known as mechanical vacuum pumps, while pumps of the second type are known as electric vacuum pumps. 

How do I know if my vacuum pump needs to be replaced?

If you lose the functionality of your vacuum operated components, then your vacuum pump is probably not pumping. It may be the pump itself or a lack of power. In the case of electric vacuum pumps, the power supply or the electric motor may wear out. Internal parts may wear out in any type of vacuum pump. The pump is lubricated by engine oil, so, any contaminants or debris in the engine oil can make the pump wear out faster. Many pumps, due to the weather, will corrode and freeze up on the inside, causing the pump assembly to malfunction.

If the vacuum pump is not working, you may not be able to activate vacuum operated systems.  For example, you may not be able to switch your A/C or heat from one vent setting to another. The most obvious and the most drastic symptom of a broken vacuum pump is that it becomes harder to use your brakes. Stopping quickly may take more effort than it used to. This may be especially noticeable if you need to use your brakes more than once in a short period of time.

It is possible to test a vacuum pump with a vacuum gauge. Any problem with your brakes poses a danger to yourself and other drivers and should be addressed immediately. 

Can I replace a vacuum pump myself?

It won’t take too much effort or any fancy tools to replace your vacuum pump and get your car or truck in safe, working order again. Because the vacuum pump works in concert with your brake master cylinder, you may need to remove the brake lines before you disconnect the vacuum pump. In the case of a mechanical vacuum pump, you will obviously need to remove the belt before removing the pump. Other than that, it’s a simple matter of disconnecting the vacuum lines, unbolting the old pump, and hooking up and mounting the new one. Due to small differences from one diesel engine to another, a service manual specific to your vehicle can provide useful guidance. 

Need a replacement vacuum pump for your car or truck?

Vehicles equipped with a diesel engine cannot generate any vacuum on their own. Thus the vacuum pump has a vital function in the proper operation of a diesel vehicle as it generates the vacuum the engine needs to activate vacuum operated systems. If it has failed, things like power brakes, 4WD systems with vacuum operated hubs, the heater, the defroster, A/C doors, emission devices, and many others will stop working. Since it has a very critical function, it's best to replace the pump as soon as possible if the need arises.

If you are looking for a vacuum pump replacement for your car or truck look no further than 1A Auto! We have brand new, not remanufactured or rebuilt, direct replacement vacuum pumps that have built to strict quality control standards. Our aftermarket vacuum pumps are all 100% tested prior to leaving the factory as well.

We also make shopping for a replacement vacuum pump for your car, truck, SUV, or van easy — we're here to help you select the right part for your vehicle! Call our customer service toll free at 888-844-3393 if you have any questions about our aftermarket vacuum pumps, both electric and mechanical, warranties, compatibility or to purchase, or you can buy online.