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Central Pneumatic Model 40400 – User Support & Info – Ask Here

Published Categorized as Air Compressor Troubleshooting, Central Pneumatic 23 Comments on Central Pneumatic Model 40400 – User Support & Info – Ask Here

The Central Pneumatic Model 44400 air compressor is one model of the Central Pneumatic house brand sold by Harbor Freight air compressors.

The 40400 is a small, DIY type air compressor, and appears to be manufactured off-shore for Harbor Freight with a 2 HP motor positioned on the top of an 8 gallon tank, with pull handle and wheels under the tank for easier movement.

The 40400 is oil lubricated, and must be filled with compressor lubricating oil before being run for the first time. Check the oil level in the sump by looking at the sight glass located under the oil fill plug on one side of the pump. If filled to the correct level, oil will be visible in the sight glass, and level with the center of the dot in the middle of the sight glass. Do not overfill. If you do, use the drain plub below the sight glass to drain off excess oil.

Central Pneumatic 40400 Air Compressor
Central Pneumatic 40400 Air Compressor

With so many questions submitted about the operation of the model 40400, it has earned its own forum page here on about-air-compressors.com. If you are looking for help with your 40400 you will find it below.

Please do read the existing posts to see if your compressor issues has already been addressed. It’s also a good idea to review the troubleshooting pages too to see if your question has already been answered there as there, are many common compressor problems have already been addressed on those pages.

If you can offer advice on another visitor’s posting about their Central Pneumatic model 40400 air compressor, please do so by adding a comment on the existing question.

40400 Manual

Download a copy of the manual for the Central Pneumatic #40400 air compressor, by clicking here.

As the numbers of comments added to this page grows, it may get harder for you to find the specific answer you are seeking so I’ve added a search box here for your use to help you find the information you need.



Existing Central Pneumatic Compressor 40440 comments

Central Pneumatic 40400 has cheap parts

Central Pneumatic Compressor 40440 – good workhorse with cheap parts, check valve seems to be

Check valve blew on 40400 compressor

I have a Central Pneumatic 2HP 8 Gal compressor (40400) about 2 or 3 years old. I use it only about

Central Pneumatic will not stay running

I have a model 40400 compressor that will not turn on, what should i look for?

Unloader valve hose for 40400 compressor

Need to know what the part number is and where to buy the unloader tube for a Central Pneumatic 40400

Parts for a Central Pneumatic 40400

I can’t find connector to fit the compressor. I have tried a 3/8 inch and it is too big and a 1/4 inch is too small.

Source for CP 40400 pressure regulator

Where can I find a pressure regulator for the 40400? Is there a substitute that may work?

Pressure switch for CP 40400

I need the part which has been circled (oval) in the photo included. According to the manual’s diagram

Central Pneumatic 40400 won’t start


New comment? New question? Please add it here along with photos to help others help you with your compressor and equipment problem!

By Bill Wade

About Air Compressors has been helping folks with their Air Compressor Problems since 2002 online. We're a community of DIY and Compressed Air professionals who are keen to support everyone across the globe with their air compressor issues and troubleshooting. Whether you're trying to identify an old air compressor, or troubleshoot an error code on a sophisticated new industrial air compressor - the community at About-Air-Compressors.com is here to help you

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