Oil blowing out of breather cap of my Campbell Hausfeld Maxus EX8403

valves,rings or piston allowing oil blow by

If the oil reservoir went dry, this will cause excessive heat and wear on the piston in the compressor. Once you refilled it, air now slips past the overly worn piston and blows oil out of the breather. This escaping air is the reason why the compressor will not get to more than 50 psi. You will need to repair (rebuild), or replace the compressor. Running it out of oil killed it.

Try here http://www.about-air-compressors.com/campbell-hausfeld-air-compressors.html

Sounds like you have a cylinder bad and the compression is blowing by the piston or rings and building up in the crankcase. This what they call blow by on a car engine.

If you are getting oil from the air pump in your hoses and tools your problem is in the cylinder/piston area. The piston on air pumps is very much like a car piston, depending on what model you have it has compression rings and oil scraper rings. If any of these are damaged or if your cylinder(s) is badly scored oil will get by the piston and be forced out with the compressed air to your tools. The only repair is to take the head and valve plate off and find out what parts you need to replace. If the cylinders are lightly scored they can be honed out but you can't machine them out as Campbell Hausfeld doesn't make oversized rings or pistons.

The only way you can have air blowing out of the breather is if the valve plate is installed backwards or incorrectly, possible because they are symetrical. If it's in wrong on one cylinder it will also let any pressure built up by the other cylinder(s) bleed off. Try turning the valve plate around 180 degrees on the cylinder blowing out the breather, if that doesn't work check the plate's assembly compared to the valve plate on the working cylinders. You should be able to tell if each cylinder is working properly just by turning the flywheel by hand and putting a finger over the breather hole and/or discharge hole.

Hello Dickie, I just want to verify that you haven't overfilled the pump. Your oil level is in the middle of the sight glass correct?
As you see in the picture, this is your pump, and in the middle, near the bottom, you want the oil level in the middle of the red dot when it isnt running.


If your oil level is correct, but it is still leaking oil, please post back.

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I am not a master electrician but I was an apprentice for 5 years and think you should be ok with a 30 amp breaker. anything less and you may be resetting the breaker when the unit first turns on. Dont forget 30 amp breakers will require # 10 wire or larger, #12 just wont do.

thats your piston rings gone buddy thats all it can be