A User’s Guide On Vacuum Pumps

Whether you’re working on a refrigerator, an automobile, or work in a laboratory, having a vacuum pump around to stuck down unnecessary air and fluids from your machines can benefit your business.

But what are vacuum pumps? How do they work? I’d argue that having a vacuum pump around will benefit you in the long run, especially if what you’ve been using as a way to suck up pressure are just a jar and a tube.

While that method is how many residents with beginner’s knowledge of automobile mechanics would generally work, a vacuum pump helps quicken the process of bleeding brakes and repairing air conditioning systems.

Because I have to spend a significant amount of time with these vacuum pumps, I can give you the best information about the best vacuum pumps on the market today.

List & Comparison of Vacuum Pumps:

Gast DOA-P704-AAGast DOA-P704-AA1.1 cfm1/8 HPView on Amazon
Robinair 15500Robinair 155005 cfm air
7.5 oz. oil
1/3 HPView on Amazon
Yellow Jacket 93580Yellow Jacket 935808 cfm air
43 oz. oil
1/2 HPView on Amazon
Welch Vacuum 2546B-01Welch Vacuum 2546B-0146 lpm1/4 HPView on Amazon
OEMTOOLS 24500OEMTOOLS 245001.8 cfm
200 ml oil
1/4 HPView on Amazon
ZENY 8523897902ZENY 85238979024 cfm1/3 HPView on Amazon
SIHI AOHA 1203 BN001010SIHI AOHA 1203 BN001010 7.5 m³/h1.1 kWView on Amazon
Edwards Vacuum A65201906Edwards Vacuum A652019062 - 2.3 cfm115/230 V, 50/60 HzView on Amazon
Pfeiffer Vacuum ALUM2005SDPfeiffer Vacuum ALUM2005SD3.8 cfm1 HPView on Amazon

Review of the Best Vacuum Pumps:

1. Gast DOA-P704-AA Diaphragm Vacuum/Pressure Pump

The Gast vacuum pump has a shaded-pole, fan-cooled motor that contains a thermal overload switch in cases of overheating. As a mechanical pump, the rugged construction of the Gast vacuum pump allows for very little tinkering to be needed.

With a 50 pressure rate, the Gast vacuum pumps run without oil and only weighs 18lbs, making it easy to carry and use.

How Did the Vacuum Pump Work?

Because I work for a used car dealership, I tend to make sure that each car for my dealership has a working brake fluid system in it so potential new buyers will be able to properly test run the cars before they leave the dealership. So, with this review, it’s allowed me to test out a wide variety of vacuum pumps to assure which pumps work the best.

As my first vacuum pump to test out, I tried this pump on a 2004 Sedan, and after jacking up the car and attaching a tube to the open nozzle, the vacuum was able to suck up the unwanted air out of the tube lining pretty quickly. I like how lightweight the pump is and the attached handle, which makes it easy for those who want a pump but don’t want to deal with the heavy-duty machines.


  • Fan-cooled motor
  • Protective thermal overload switch
  • 50 psig pressure rate
  • Doesn’t use oil fuel
  • Overall dimensions: W: 13” D: 10.2” H: 13”

2. Robinair (15500) VacuMaster Economy Vacuum Pump

The Robinair air conditioning vacuum pump works specifically with helping bleed our air conditioning fluid from automotive, industrial, and residential A/C systems. As a heavy-duty rotary vane pump, it has a 5 CFM air displacement system and a 7.5-ounce oil reserve capacity to run for long periods without rest or resetting.

The aluminum material helps displace heat and has an easily-accessible oil drain port for more complete draining.

How Did the Vacuum Pump Work?

One vehicle I had to help repair, a 2010 Dodge Ram, had some air conditioning problems that led to the owners of the truck selling it off to our dealership for a vehicle upgrade. To best repair the air conditioning system, I had to use a leak detection system to see where the leaks were coming from before I could test out the Robinair pump.

Once I found the leak, I attached the mechanism with the Ram’s air conditioning system, and while the Robinair’s CFM rate wasn’t the fastest, it was able to disperse any leftover air molecules in the conditioning fluid.

Although I noticed the faintest smell of oil coming from the Robinair, I figured that it was working just fine, as it didn’t overheat.


  • 7.5 ounce oil reserve
  • 5 CFM air displacement system
  • Aluminum exterior for protection
  • Overall dimensions: W: 14.3” D: 13.6”H: 8.3”

3. Yellow Jacket 93580 Superevac Vacuum Pump

The Yellow Jacket vacuum pump has 8 CFMs and a built-in indicator gauge for monitoring oil levels. With a wide mouth oil reservoir for cleaner filling, a large oil sight glass and brass oil drain for oil changes, the internal intake of this vacuum pump helps to prevent oil backups and keeps particles from damaging the pump.

With an internal intake valve system backup for power failure, this tiny, but powerful machine can be used to clean out any sticky situation and help keep your vehicles in tack.

How Did the Vacuum Pump Work?

The micron readings on this pump varied from 350 microns to 230 microns, which gives the machine a lack of consistency. However, because I was working with a 2009 Pontiac vibe that had a significant oil problem on its hands, it was able to purge the oil of unwanted sludge and air from the oil system itself.

The pump itself is particularly tiny, weighing in at only 12 lbs and is made pretty well. The mechanisms are simple enough anyone who doesn’t know much about changing fluids to use, and I’d recommend this pump for residential use.


  • Built-in vacuum indicator gauge
  • Wide-mouth oil reservoir port
  • Internal intake check valve
  • Heavy duty rotors and bearings
  • Isolation valve for oil changes
  • Overall dimensions: W: 19” D: 8.2” H: 13”

4. Welch Vacuum 2546B-01 Standard Duty Pump

A simple to adjust vacuum gauges, the Welch piston vacuum pump is a laboratory vacuum pump that filters out impurities and helps suspend samples. To control the solvents, this standard duty pump can help evaluate air molecules, and help prevent negative pressures of hazardous material from escaping.

However, the Welch vacuum pump can also be applied for testing of an automobile and standard fuel equipment.

How Did the Vacuum Pump Work?

While I’m not a scientist, I decided to make some amendments to the vacuum itself to see how it’s working at displacing and transferring air out of a brake line. While working on a vehicle I had to repair, I noticed that this vacuum pump had a significant amount of power behind it, more power than I’d usually expect.

I had to tell one of my friends to only push on the brakes a few times because of the significant pull the Welch’s has for sucking up air molecules. After my tweaks, I could say that this is an excellent pump that’s versatile and can be used for anything if you’d want.


  • One-head WOB-L-style piston pump
  • 46 liter per minute (LPM)
  • Air displacement up to 60 Torr
  • Adjustable pressure levels with gauges
  • Oil-free pump
  • 1/4 HP motor
  • 60Hz input power
  • Overall dimensions: W: 16.2” D: 12.7” H: 13”

5. OEMTOOLS 24500 1.8 CFM Single Stage Vacuum Pump

As a rotary-vane motor, the OEM TOOLS single stage vacuum pump is built for cleaning out air conditioner fluids at a significantly fast rate of 110V.

Ensuring moisture removal, this high-pressure pump runs quiet, has an intake screen to prevent foreign matter from clogging the pump, and internal exhaust chamber for separating oil from the exhaust, and is made with aluminum for efficient cooling.

How Did the Vacuum Pump Work?

I hoped that the Oem vacuum pump would work just as well as the Robinair, so I tested it out on the pump on a Ford to see how it helps with its air conditioning problems.

It was able to separate some of the air and dirt that got caught in the system itself, and while it’s not the most powerful, it has a great oil capacity, which allowed me to continue finishing the job without much hassle.

I found it to work extremely quiet, and I’d say this small vacuum pump can easily be used as a spare transportable one for when you’re working on the go.


  • Internal high volume cooling fan
  • Vacuum Pressure: 100 Micron
  • 110V motor
  • Oil capacity: 200 ml
  • Overall dimensions: W: 11.7” D: 5.8” H: 9.1”

6. ZENY 4CFM 1/3HP Electric Vacuum Pump

The Zeny 134a vacuum pump can be used for circuit board milling, air conditioning filtering, and just about anything if you put your mind to it. The 134a vacuum pump comes with a heavy-duty aluminum alloy casing, exhaust port for easy startup, an oil sight glass for monitoring, and a non-slip group for easy handling.

Tiny but mighty, the Zeny vacuum pump is inexpensive, making it a great deal for those who don’t have much experience with vacuum pumps but would like to start.

How Did the Vacuum Pump Work?

While it’s not my favorite out of the ones I’ve reviewed so far, I’d say that its efficiency is up to par with much of the standard vacuum pumps out on the market. The oil sight glass allows me to see what I’m pulling out from the pipes, the cooling fan works well at cooling off the pump, and the aluminum alloy gives it quite a sturdy frame.

Nevertheless, while I wouldn’t use this pump for everyday work, I’d find it just as comparable to the Gast and Yellow Jacket pumps with the only difference being that it is in a smaller package.


  • Heavy-duty Aluminum Alloy Casing
  • Oil drain plug and reservoir
  • Internal High Volume Cooling Fan
  • Exhaust Port with Exhaust Cap
  • Direct Drive Motor
  • Oil Sight Glass For Monitoring Oil Levels
  • Non Slip Cushion Handle
  • Overall dimensions: W: 12.6” D: 10.6” H: 6.3”

7. SIHI Vacuum Pump, Model AOHA 1203 BN001010

The Sihi company offers both liquid ring and dry vacuum pumps, and this vacuum pump comes with a sterling fluid system that allows for ease of suction.

With an iron casing and stainless steel shaft, this vacuum pump has the name in heavy-duty, as it can easily be attached to any working system and has a compact design that allows the liquid to be sucked in and transferred up to two stages before being stored in the vacuum’s compartments.

How Did the Vacuum Pump Work?

I wasn’t very familiar with the mechanics of this model, as I didn’t have the right hose and nozzle connectors to be able to attach and operate this vacuum pump, so I ended up having to by some spare parts from an automobile store in order for it to work the way I wanted it to.

However, once I got all the working pieces together, it was able to transfer much of the air and gas that was leftover in one of the vehicles I had in line to repair and restore.

It works much like an entrapment pump, giving it at least some reliability when it came to the job. I would recommend this pump as a spare part for projects, especially if you’re wanting to create something specific.


  • Two stage liquid ring system
  • Iron casing
  • Iron rotor
  • Stainless steel shaft

8. Edwards RV3 Vacuum Pump

A rotary-vane pump with a kick, the Edwards RVS vacuum pump is uniquely capable of handling high and low through-puts for the best performance. With an easy to use as ballast, a fast inlet valve for protection and oil-tight gaskets for effective seals, this pump comes with a high torque that leaves each use as consistent as ever.

Configured to run at an ultra-low noise level, it is ideal for many applications, including distillation, backing vapor pumps, freeze-drying, and laboratory furnaces.

How Did the Vacuum Pump Work?

Considerably the most expensive out of the vacuum pumps I’ve reviewed, I was careful enough to test both the high and low settings on a few vehicles that needed some cleaning in their pipes.

I tested both the air conditioning fluids, the brake fluids, and oil fluids in a few cars that I had lined up at my disposal, and I must say, for the price, it works excellent. This pump would be best used for more high-end projects however, as I feel I’m kind of disrespecting this very pretty machine for such work as air conditioning filtering.


  • Adjustable gas ballast
  • Inlet valve and vapor handling capacity
  • Wide range voltage motor
  • Oil and hydrocarbon oil included
  • Dual mode settings
  • High pressure lubrication
  • Oil-tight printed gaskets
  • Clamped-in sight glass
  • Hi-tech polymer blades

9. Pfeiffer / Adixen 2005SD 3.8 CFM Two-Stage Rotary Vane Vacuum Pump

The Pfeiffer Rotary Vane Pump is a dual-stage vacuum pump that is compact with a single-phase motor. The pump motor can be disassembled for pump oil changes, is built with a sight glass for inspection of oil levels, a gas ballast for analyzing gas vapors, and an inlet and exhaust end for easy access.

With an insulated fold-able handle for carrying and various accessories, the Pfeiffer vacuum pump can be utilized for adjustments to meet any application.

How Did the Vacuum Pump Work?

Again, just like the Edwards model, it’s quite an expensive and impressive piece of equipment. I had to purchase some accessories online however to meet the purpose of my application, that is, and once I was able to assemble the right parts, I was able to test this vacuum pump out on some semi-trucks that needed some brake repairs for their deliveries.

However, due to the extent of the brake fluids, the pump sucked up something it shouldn’t. However, its backup system was able to shut down the pump before anything bad happened, so I was thankful for that aspect of this machine.

After clearing the pump of the dirt that was in the pump, I tested out the pump again with the trucker’s help, and I was able to clear out the air in his brake system just fine. So, for your money’s worth, I’d say this is quite a useful machine.


  • Direct drive motor
  • Electrically-insulated fold-away handle
  • Anti-suck-back system
  • Vertical sight glass
  • Adjustable Gas ballast
  • Standardized inlet and exhaust fittings
  • Overall dimensions: W: 29” D: 14” H: 15”


How to Bleed Brakes with a Vacuum Pump:

Bleeding brakes of air bubbles in the pipes can help increase hydraulic pressure and help the vacuum pump transfer fluids at a much faster rate. Typically, when you’re bleeding brakes, you’re getting air that’s stuck within the brakes out.

Behind each brake system, there’s a nozzle called a brake bleeder screw that’s located behind the brakes, which can typically be reached by either jacking up the vehicle or crawling underneath it. By loosening the screw with the proper wrench, you’ll be able to have access to the inside of the brake system where the trapped air is.

While many typically transfer the air out of the brakes using a jar and a hose, vacuum pumps help quicken the process and can capture any air or other fluids from the brake system at a much faster rate.

After attaching the hose to the end of the bleeder screw, have a friend pump the pedal a few times to allow the trapped air to transfer out of the system and into the jar or pump. Brake fluid will typically squirt out from this process, and after telling your friend to hold the brake down, screw back on the nozzle to prevent air from being sucked back into the brakes.

Once your friend releases the brakes, you can add more brake fluid to your system and take your vehicle out for a test drive to make sure the brakes work well.

How Does a Vacuum Pump Work?

Vacuum pumps help transfer old air, gas, or water out of an area into another area, and it can also be used to transfer new gas or water into a mechanism as well. Vacuum pumps are typically used in industrial settings to produce vacuum tubes and electric lamps, and can also be used to power a piece of equipment.

Vacuum pumps can typically be used and modified for other areas of expertise, such as bleeding brakes for instance. There are four kinds of classifications that pumps use.

Entrapment pumps trap molecules into a confined space, such as a cryopump, which pulls liquid into a trap. Transfer pumps use the momentum to accelerate gas from a vacuum to the exhaust side, such as a turbomolecular pump.

Compressed-air pumps rely on pressure differentials to create a vacuum, and a mechanical pump usually has an electric motor or power source to draw air from a closed volume to then be released to the atmosphere, such as the rotary-vane vacuum pump.

These kinds of pumps can be adjusted and modified for multiple uses, and in my review of vacuum pumps, the kinds of pumps I’ll be reviewing will most specifically work for helping bleed brakes.

All of these kinds of classifications can technically work for bleeding brakes, but specifically, air compressor pumps, entrapment pumps, and mechanical pumps tend to work best at taking air and dirt out of the brake system without causing too much of a mess.

Things to Consider Before Buying a Vacuum Pump:

Now, before you go purchasing the next vacuum pump you see, there are aspects of vacuum pumps that are vital to how it works. Some of the things you’d need to consider when purchasing a vacuum pump


When you’re looking for a vacuum pump, check the CFM. The CFM, or cubic feet per minute, tells you the vacuum flow speed. The vacuum speed flow determines how quickly you can get the air out of a system or a tank.

Sizable diameter

If the vacuum pump has a good sizable diameter, then it’s an excellent choice. This makes it so that way it is easy to fill it up with oil and reduces how much of a mess it makes.

Micron Rating

Micron ratings refer to how strong the suction of a vacuum pump can be. The lower the micron is, the better quality the suction of the pump is.

Sight Glass

The sight glass should help you determine if the pump is already full of oil. If you can see clearly through the glass without having to squint at the reading labels, then that means that the company designed the pump well.

Oil Plug

Oil plugs must have a sizable opening for drainage. The bigger the opening, the better and more convenient it will be for you to use.

Gauge Indicator

If the gauge indicator can give you a good view of how the vacuum is working, then it’s a good sign.

Gas ballast valve

Some come with a gas ballast valve. When this valve is open, some air gets into the pump to assist in exhausting water vapor, which can be particularly useful for early evacuation levels.

Isolation valve

An isolation valve allows you to shut the unit off and use it for pump refilling or oil draining. This allows you to easily manage the oil levels in your vacuum pump.

Exhaust filling

If you have a vacuum pump that has an exhaust filling that is compatible with garden hoses allows, then it will create an easier time for outer venting, especially if you’re working indoors.


What’s my top choice for vacuum pumps?

I had the easiest time with the Aerospace complete kit for its versatility and wide range of uses. It comes with everything anyone would need for repairing vehicles, and has the most flexibility with adjustments and can be amendable for multiple projects that aren’t related to cars and truck repairs.

Although the machine lacks the power that the Pfeiffer and Edwards had, it isn’t as expensive as most high-end vacuum pumps, because, with those other pumps, I’d had to consistently upkeep and adjust my nozzle and tube settings depending on the type of job I had at the time. The Aerospace is the perfect set for mechanics alike, and for those within that business, I’d recommend that as my best choice.

Other considerable notions that I had in mind were the Gast and Welch vacuum pumps for their consistency. As some of the first few vacuum pumps I’d reviewed over the past few months, I’d say that for the average Joe, I would be confident in these selections for their consistent power and suction capabilities.

The Robinair is a second close best, because when I was repairing the air conditioning system, it was able to transfer air out of the air conditioning fluid at a significant rate, thus for those guys out there who work on refrigerators for a living, then this machine I’d suggest you’d give a try.

I also liked the Zeny for its tiny quality and would recommend this vacuum pump for times when you’re on the go and need to repair the way.

About the author

Jessica Nickson

Jessica Nickson

Jessica Nickson is a keen home and garden innovator with over 25 years of hands-on experience in, home improvement, landscape gardening and all things appliance related to making life easier and more interesting. You can contact her via e-mail - jessica@thehomedweller.com.

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