# Graco 390 rebuild



## Jackpine Savage (Dec 27, 2010)

I did my first rebuild of the pump on the company's Graco 390. Not so much a question (too late for that!) as a rant.

First of all, I wish they could do a little better on the instructions. I had the back of the rebuild kit package and a pdf from the Graco website on my iPhone to go on. But basically just a small schematic with completely useless parts numbers. 

You'd think you could just take it apart and put it back together with the same but new parts, but A) the packings were so toasted that it was hard to tell what was what, B) there was so much dried paint (from the leaking packings) that sometimes it was literally hard to tell if what you had was a bushing or a disk of dried paint, C) the sprayer had been rebuilt once before in the paint store, and I'm pretty sure it didn't get put back together according to Hoyle--for one it was missing a little bushing thing below the lower ball valve, and D) my memory is so bad that I can hide my own Easter eggs!

Then the kit fits 3 different sprayers, so you wind up with all these spare O rings etc. that make you feel a bit uneasy. At the end, the picture showed a washer-O ring thing above the packing nut, but I couldn't for the life of me figure out how that stayed put. 

In the end I got it together and it does seem to have good pressure. It does seem to leak a bit of pressure...when you leave the sprayer on, it cycles one stroke every now and then. Not sure what's up with that or maybe that's even normal? It was also having trouble with the prime valve acting up so I'm wondering if it's that--pushing a bit through the prime hose. I took it apart and cleaned that, as best I could. The real test will be a few fivers of paint.

Anyway, that was my morning. Thanks for reading.


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## Pete'sfeets (Mar 20, 2011)

sometimes a look at the inside piston with your finger you can tell whether there is wear. I found cleaning the intake pipe by soaking is good, to clear out any old paint that might cut loose and find itm's way onto the ball bearings that hold the pressure. I upgraded to the 490 ,it comes with a replacement packing as a unit, much pricier but a no brainer to switch, I replaced the packings plenty of times on a 390 till that one day the super glue didn't hold, the damage was last time. It's good to fix stuff yourself but there's always that scary thought, did I get it too tight? if only the service was like getting a burger, packings always go when you are in emergency mode.


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## Ohio painter (Dec 4, 2011)

I felt the same way when I repacked my Nova 395.


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## artiospainting (Mar 16, 2011)

After you do it a few time it gets easier that will separate you from the other gays on the job. To whos who KEEP IT UP.


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## JHC (Jun 4, 2010)

That is why I have a repair guy rebuild/repack my pumps. $300 is something I don't consider outrageous. I don't service or repair my own vehicles either, not that I couldn't. I value what a professional can do.



artiospainting said:


> After you do it a few time it gets easier that will separate you from the_ other gays on the job_. To whos who KEEP IT UP.



:blink:


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