My Gast 1023 swallowed sap! What I did wrong..

[DoubleBrookMaple]

Two days ago I was processing with my RO, and I switched my Homemade vacuum system submersible pump outlet hose to another tank. I had unplugged the pump to avoid running while doing so. BAD IDEA! I forgot to plug back in. Some time later, I heard the sound of my Gast sucking sap! Ohhh Noooo! My sap trap cutoff switch had just worked a few days ago, but I later found the ground wire broken.
This is a story of what I did wrong..
I tried to "blow it out", by toggling the switch, and it did not sound right after it ran some, so I removed the cover, vanes, and cleaned it up with Gast cleaner. I reassembled it, and it ran, but did not sound healthy. I should not have continued to run it, but to hasty in my decisions some times. Before long it stopped, and seized up! I turned the switch off, and removed the pump and took in on the bench.
The vanes had failed, and jammed up in the eccentric housing and vane rotor. It took tremendous effort to free up the rotor by reverse rotation. I removed all the pieces and cleaned up again with spray cleaner. I could not rotate the vane rotor freely, as it would jam against the eccentric housing. I thought the motor shaft was bent, but no. I removed the housing retained by two cap bolts, and found the rotor and housing scored, with a couple gouges. I spent an hour or so sanding the housing surface and the rotor with emery paper and solvent. 100/220/320/400/600 grit... (Hey, I am well stocked) The rotor was easy. I just turned on the motor, and let it do the work like a lathe. The housing, was a different story, and the damage was only on the upper, close tolerance area, but it was not so bad. I also sanded the rotor vane slots to remove any residual burned sap. I installed new vanes, reassembled and the pump sounded good! It has been running for 20 hours now without a problem.
As I anticipated, I lost some vacuum from the increased clearance as a result of rotor and housing material removal. I lost about 1" - 1 1/2" of vacuum in operation. Vacuum needs very close clearances. I can see why these pumps are so expensive.
What I did wrong...
Running the pump. I should have removed it IMMEDIATELY! I should have cleaned it up like I did, and I would have avoided the damage to the rotor and housing. Dumb to think I could blow out the sap, and it's residue.

[DoubleBrookMaple]

I lost some vacuum from the increased clearance as a result of rotor and housing material removal. I lost about 1" - 1 1/2" of vacuum in operation. Vacuum needs very close clearances. I can see why these pumps are so expensive.

I FIXED IT!
My above statement was wrong.
Today I tore down the pump again, and found the concentric "body", as it is called on the parts diagram Item 3, was not cleaned up (sanded) enough, and the vanes were wearing in improperly. I spent 2 hours sanding with emery paper again, and used a 16oz syrup jug for the "sanding block" on the inside circumference, by rolling the body with the jug and emery inside like a stationary rolling pin. There was still some damage on the upper surface where the vane rotor nearly contacts the body. Sanded, sanded, sanded, and did the same with all the mating surfaces of the pump. Cleaned well with solvent, blew it out, cleaned with Gast cleaner, and assembled and tested.
Vacuum improved from 21" to 23", but I was not satisfied. When I installed the body with the two cap screws, I adjusted the body-to-rotor clearance at .0025, trying to be conservative. I tore it down again, and reduced the clearance to .0010 and the vacuum is now at 24", which is the best I can do. The pump is rated at 26", and I am at 2000'. Rule of thumb is 1" loss per 1000'
Now I don't have to look at the prices of vacuum pumps any more. This whole ordeal did cost me a lot, with two kits, and an overnight shipping charge. Nothing compared to the cost of pumps.