pressure pot for gear oil changes

Joined
Nov 17, 2006
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895
I replied to a post in the 40s section describing a pressure pot I made out of a propane tank. After a few PMs, I decided to post the how to here, it's really simple, and i can fill the oil in both diffs and my transfer case and transmission in under 20 minutes, no pumping, minimal mess...I built it originally to fill outdrives on my boat, works fantastic...

Here goes

What you need:

-a propane tank, in decent shape, I bead blasted mine, valve removed, FILL IT WITH WATER AND DRAIN IT
-a 3/4" ball valve
-a 4" nipple that fits the 3/4" ball valve, and also fits the propane tank valve outlet
-a 1/2" ball valve
-10" of pipe threaded at one end, that fits the 1/2" ball valve,
-a hose barb that fits into the 1/2" ball valve
-5 feet of hose that fits the barb
-a new valve stem from a rim

ok, take the valve stem, determine what size it fits, drill a hole in the top to the tank to fit.

drill a hole to fit the 1/2" pipe, also in the top of the tank, hog it out so it goes straght down.

cut a 45 bevel off the end of the 10" pipe, slip into the hole all the way to the bottom of the tank, and weld.

onto the 10" pipe, attach 1/2 ball valve, then barb into the valve, then hose onto barb.

put the 4" nipple into the tank's valve hole, add the 3/4" ball valve here...

install the valve stem.

see the pic below, open the blue 3/4 valve, fill to 3/4 full, close blue valve, check red 1/2 valve closed, pressurize tank, open red 1/2 valve, air pushes oil down and back up the pipe, and out thru the hose...
pot.jpg
 
Last edited:

semlin

curmudgeon
 
 
Joined
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it looks good, but how much oil has to remain in the tank for it to work? also, wouldn't it be easier to make a step down for the 3/4" ball valve to an ntp coupler than to drill and tap for the valve stem?
 
Joined
Nov 17, 2006
Messages
895
With the 45 cut and the tip on the bottom, you only need to cover that opening, or about 3/4' of oil, allowing for the curve at the bottom, maybe 1-1/4 inches...I've never let it get that close,

the tank is already threaded for the nipple...the old propane valve was threaded into the hole, no tapping req'd, I just threaded the nipple in and it was done...
 

-Spike-

 
Joined
May 26, 2005
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Phoenix
I use an actual paint pressure pot for gear oil, works great and has a regulator. I run it at 10 psi. Easy to fill too. You can find them used pretty cheap sometimes, and Harbor Freight carries them for I don't know how much.

-Spike
 
Joined
Nov 17, 2006
Messages
895
I run mine at about 25 pounds, I fill it from a 5 gallon pail of gear oil thru a big funnel,
 

-Spike-

 
Joined
May 26, 2005
Messages
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Location
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FWIW, I use a garden hose pistol-type sprayer on the end of a clear hose to turn on and regulate flow. I threaded a hose repair barb on the end of the sprayer to focus the oil. I can see the oil coming through the hose, and air bubbles when the tank is almost empty. I can try to get a pic up later.

I've toyed with the idea of pressurizing a 30 gallon drum, but I'm too scared to do it. :D

-Spike
 

bkfj40

SILVER Star
 
 
 
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I use a big fire extinguisher...the type that had just water in them. Got it with a bunch of other crap at an auction. works great!


bk
 
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