First post Question about Makita Compressor

Old 09-25-05, 06:30 PM
Visiting Guest
Posts: n/a
First post Question about Makita Compressor

I just received a Makita MAC2400 Compressor and have a question.
I went through the 20 minute break-in time as called for. After which, I started the compressor and it seems to be running fine. The problem is that it has been running for at least 30 minutes and hasnít built up pressure past 40 pounds. It has not shut off and I canít seem to locate any leaks. When I turn the compressor off there are no noises indicating that there is a leak anywhere. How long should this compressor take to get up to operating pressure 90lbs?
Old 09-25-05, 07:40 PM
IBM5081's Avatar
Join Date: Oct 2004
Location: Texas
Posts: 655
Received 0 Votes on 0 Posts
The only leak that I can identify in this situation would be the seals on the piston such that they can only resist blowby up to 40 psi. You DID put the correct quantity of the recommended air compressor oil into the pump and check to ensure that it was neither overfilled nor underfilled, right?

My Hitachi EC12 should contain 4 oz. of oil. The first time that I changed it, I drained off 8 oz. of oil and replaced it with the correct 4 oz. It does not seem to be the worse for wear. All that I could consider was that the shop where I bought it dumped in 4 oz. without checking. I ran it for quite a few months before changing the oil.
Old 09-25-05, 07:51 PM
Visiting Guest
Posts: n/a
Thanks for the reply IBM5081
I filled the case with the oil supplied with the compressor. It has a site glass on the side and the instructions only stated to fill to proper level indicated on the site glass. There is a red dot in the center on the glass, I guess that would be the proper level? I checked all the connections with soapy water and found one loose (not bad) I tightened it and still after an hour it gets up to 60lbs. What is the result of having too much oil? When I start the compressor it runs pretty quiet, but after a bit it gets louder, wonder whatís up with that?
Old 09-26-05, 06:49 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 49,254
Received 681 Votes on 602 Posts
I don't know if this applies or not but a belt driven pump with a loose belt will quit producing air after it hits a certain level of resistance. I tore my little sears 1hp down a long time ago suspecting mechanical failure only to find out that the belt was slipping.
Old 09-26-05, 02:55 PM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 10,234
Received 65 Votes on 60 Posts

If you have checked for leaks the only place I can think of you might have missed is the drain petcock which must be open when running for the 20 min break in and the pressure release on the cut-
out switch. There should be a 1/4" line leading from the check valve at the tank to the pressure switch and the valve.

It is also possible that the reed valve(s) in the compressor are defective.
If a valve is leaking you would find that the compressor head gets hot fairly quickly.
If the head gets hot you also could have a plugged or restricted check valve which is where the compressor outlet connects to the tank.

If you can't redily see what's wrong you would do well to take it back rather than start taking things apart to diagnose the problem;.

Thread Tools
Search this Thread
Ask a Question
Question Title: