Question about Makita Air Tools & Compressors

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Makita mac2400 compressor-The regulator knob now controls both gauges. The reg gauge is to the aluminum block, the tank gauge to one of the spare ports. I've tried swapping the tank line and the plug.

Posted by Anonymous on

  • Jan Huge Jun 05, 2015

    I replaced my reg and have the same problem. Tried switching around hoses and ports but no luck- have you resolved the issue? Thanks.



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  • Makita Master
  • 44,437 Answers

Regulators should be connected to the outlet line of the compressor tank
the purpose of a regulator is to control ( regulate) ) the air pressure that is being supplied to what ever tool you are using from the tank pressure
so one gauge ( the one that reads up to 1000kpa or 120psi should be on the tank side and the lower reading gauge on the line to the tool

Posted on Jun 11, 2015


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Posted on Jan 02, 2017

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SOURCE: oil dipstick and red twist knob on top of the two pressure gauges

the big red knob adjusts working pressure to hose- refer to book or dowload online

Posted on Dec 17, 2008

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SOURCE: when i turn on the compressor, the regulator gauge

sounds like you blew out your valve(s) you probably need to replace your valve plate

Posted on Mar 19, 2010

  • 24 Answers

SOURCE: Makita MAC2400 2.5 hp compressor

Replace the regulator, you can get a new one from the home depot or just about any good hardware store.

Posted on May 05, 2011

  • 1 Answer

SOURCE: my regulator adjustment knob is not working and

i had same problem and found that the plastic knob had expanded to the point where it would jump threads and coud only get pressure to about 30 lbs. i installed a reg. stainless hose strap around the knob in area of threaded section. after compressing the knob , it worked like new

Posted on Aug 07, 2011

  • 1 Answer

SOURCE: My porter cable C2002 Type

I have same problem with my PC2002 type 3 AC and come to find out after removing the know for the regulator, inside there is a spring(remove it),underneath is a seal with a nipple in the center that is used to let the air though. It is made of plastic(so mine broke).Tough job is finding that seal.

Posted on Mar 19, 2012

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1 Answer

Where can I buy a Makita Mac2400 air compressor regulator

Makita parts are available at A small universal regulator may also work if the fittings match-up. When using a universal regulator make sure that the regulator fits thru the hole in the panel or just adjust the hole size. Universal regulator costs about 20 dollars. Good luck

Mar 03, 2015 | Makita & Sealed Mac2400 Big Bore 2.5 Hp...

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I have a Makita MAC5200 and the guage is showing 120PSI , tank has pressure, yet I can't get any air from valves. Any suggestions would be appreciated.

Plunger inside the regulator could be stuck or adjustment knob stripped. Let the air out of the tank and take the regulator apart, lube with light grease (no kit available for this reg.). The factory part is expensive so replace (if needed) with generic, careful with size however because there is not much room under the panel and between the gauges . Easy temporary fix. Remove the safety pop valve and install a tee (or check under the pressure switch for spare port) re- install pop valve on the tee fitting. On the second port of tee fitting install a quick connect valve for full pressure. Generic regulator is sold at Lowes that can be installed on the temporary port.

Nov 03, 2011 | Makita MAC5200 Electric Powered Air...

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My Makita air compressor will not adjust to a lower pressure. I am putting cedar shakes on the house and I dont want the nails to push so hard in the shakes. When I adjust the nob in the minus (-)...

It sounds to me like your regulator is shot. It is the knob you have been turning in the (-) direction. The gauge reading 120 is the regulated pressure and the gauge reading 130 should be the tank pressure. You can find a new regulator from any Ace Hardware store.

Aug 03, 2011 | Makita MAC700 2 HP Air Compressor "The Hot...

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The regulator is leaking air and will not support the air tool I am using

They do not show the regulator as serviceable. It looks like you have to buy a complete new regulator. It is part #410028-E. You can find it on this link reference #42.

Jul 13, 2011 | Makita Mac2400 212 Hp 42gallon Twin Air...

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Makita MAC2400 2.5 hp compressor has started leaking from the regulator. Is there a repair for this? Thanks

Replace the regulator, you can get a new one from the home depot or just about any good hardware store.

May 02, 2011 | Makita Mac2400 212 Hp 42gallon Twin Air...

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The pressure gauge doesnt go higher than 40 50 psi on dial, pressure seems to go higher than whats on the gauge as i turn the pressure knob. I have restarted it many times and lowered and raised the knob...

Try a separate gauge on the outlet line, like a tyre pressure gauge, and see what that reads. If it differs from you compressor gauge, the gauge is faulty or the needle is stuck, in either case the gauge will need to be looked at or replaced. You can probably pick up another gauge of the same size and scale quite reasonably and engineer it to fit if you cannot get the same gauge.

Feb 27, 2011 | Makita MAC2400 Electric Powered Air...

2 Answers

I just bought this unit took it home read the instructions loaded the gun with nails hooked up the cables opened the gauge turned on the unit and i waited for the tank to fill with air and the gauge...

There are usually two gages, one for the pressure in the tank, the other is for the regulated pressure in the hose going to whatever tool you have connected. I assume the tank filled up and the tank gage registers pressure in the tank. When you said you "opened the gage" I am guessing that you turned the knob counter-clockwise which would be the normal direction to open a valve. However, this is not a valve, it is a spring loaded regulator device. When you turn the knob counterclockwise you are removing all pressure from the spring which sets the regulator to allow zero pressure in the hose. Turn the knob clockwise to increase the pressure in the hose. I hope this was helpful. Good luck.

Feb 18, 2011 | Porter Cable Air Tools & Compressors

1 Answer

Mikita air compressor 5200 regulator knob leaks air

There are two types of regulators used. One has a rubber diaphram sealed at perimeter with body and a piston type. Most likely you have the piston type. Remove body containing piston/ spring mech. Examine piston lip seal. Lip will face toward body of reg. and must fit snugly into cylinder. Make sure cylinder is smooth and is well lubed.
If seal/piston fits loose remove seal and wrap some teflon tape in groove and re-install lip seal /test for snug fit. Notice small metal actuator extending from center of reg. , if it is circular (about 1/8 dia) then there should be an oring of the same size mated/fit into the piston. If this oring is missing it will leak as you describe. Lastly, there should be a gasket or oring sealing outer shell to body. If you have diaphragm type look for holes, tear or shrink too small. Parts are at or Lowes in the plumbing department good place for orings and silicone lube. Good luck

Jan 08, 2011 | Makita MAC2400 Electric Powered Air...

1 Answer

Will not build up pressure

You did not state whether the compressor would kick on automatically, or whether it would kick off at some point, so I have to work through it with you....
If the compressor runs, you should see pressure on one of the two gauges. The gauge that is closest to the tank is the pressure that the compressor proper is putting out to the tank, and is the primary gauge. The other gauge is the pressure supplied to the tool via the hose, downstream of the regulator. If you are seeing pressure at the first gauge, that's a good sign. Also a good sign is if the commpressor runs and switches off at some point before lifting the PRD (pressure relief device). This tells you that the compressor is pumping and that the pressure switch is working. If this is the case, try working the regulator control knob and watch the second gauge. The regulators can be tricky; sometimes the regulator knob operates in the opposite direction than expected, depending on the type of regulator, so experiment a bit. (Usually there is wording and an arrow on the knob telling you the direction to adjust. If you start to see a rise in the pressure on the gauge, go ahead and set the desired tool supply pressure.
If you can get a pressure on the first gauge, but nothing on the second gauge no matter how you manipulated the regulator, you should suspect a bad regulator.
If there is no pressure on the first gauge, try cracking open the drain valve on the tank and starting the compressor. If you get air out of the tank with no indication on the gauge, you should suspect a bad primary gauge. If you get no air out of the tank, open the drain valve further and check again. If still no air, the compressor itself is suspect. You will need to determine that the motor is in fact turning the compressor. If the motor is running, but the compressor isn't moving, unplug the compressor and reconnect the linkage. If the compressor will run with the motor, the compressor may be shot, or tha air intake may be plugged off. Remove the cover on the air intake and inspect the filter. Clean and replace as required.
If the compressor will start when you operate the on/off switch, but does not kick off at some point, the pressure switch is probably at fault. It is an odd piece of is mechanical, electrical and pneumatic, all at once. You would need to troubleshoot each portion in order to put it right. The most common problem with the pressure switch is burned or welded contacts, followed by wiring issues to the contacts, then the air line to the switch, then mechanical linkages within the switch.
This humble guide should be enough to get you going. I hope that it has been useful.

Regards, and good luck!


Jul 18, 2009 | Campbell Hausfeld 02-Gallon Air...

1 Answer

Air compressor pressure not regulating

Usually you cannot adjust the cut out pressure of the tank/motor itself, this is why they have regulators, which regulates the pressure flowing down the air lines (regulators like these dont regulate actual tank pressure cutout). To regulate air flow using the regulator knob, you actually have to have air flowing through the hose while you make the regulator/pressure adjustments as regulators regulate pressure DOWNSTREAM from the actual regulator itself.. so air flowing through is a must. Attach an air blower or something similar and let air start flowing through the hose. Now turn your regulator knob in the "-" direction to decrease regulated pressure. It is best to bring pressure all the way down to "0" first, then open the regulator up (by turning to the "+" side) and pressure will rise until you get to the desired pressure needed for the air tool in use. The tank pressure will still be between 80-125 PSI as the motor regulates and keeps the pressure in the tank between these values automatically, but your line/hose air flow pressure will remain at the regulated pressure (say 40 PSI or whatever you set using the regulator knob).

Hope that helps and makes sense.

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Jun 18, 2009 | Makita Factory-Reconditioned 2.5 HP Air...

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