# Graco Airless: piston and pressure leak



## chaiteachaitea (Jan 11, 2015)

Hello painters.
I am working with a Graco Airless Performance Max 395. It has been not holding pressure, so I repacked it and cleaned it. Maybe not well enough?

The current problem is that the gun gets to pressure, sprays pretty nicely, but if it is sitting for a few seconds, the pump will stroke again. I noticed that the piston slowly creeps UP once it has stroked to full pressure, and once it gets to the top it often does one more stroke. Does anyone have an idea what is going on? Is this an issue with the lower ball check? or the high ball check? thanks! :cowboy:

Here is a youtube link to a video of what the pump is doing: 




thanks!


----------



## SprayRepairGuy (Jan 15, 2014)

That could just be your hose expanding as the sprayer rebuilds pressure. If it stays that way and does not cycle again, you do not have a leak and everything should be fine. If it continues to cycle every so often, then you might have a small valve or packing leak that will eventually get worse over time and cycle more often as the leak increases.


----------



## evodawg (Oct 27, 2017)

Think its normal for the piston and connecting rod to move up and settle there. Does your spray gun drip at all? If so then that could be the problem. And how fast before the motor comes back on? Mine had a small drip at the gun and it would take the motor 5 minutes to cycle. When it did it just came on for less then a second. And yes the piston shaft did move up and jiggled a little and stopped. Or it could be what Sprayrepairguy said.


----------

