Oil Tank & Tool Cover

Cleaned up and repaired the oil tank and the tool cover, and got them mounted.

The tank looked to be in decent shape. It had cracked and been repaired once many years ago. You can see the brazed repair under the paint at the base of the forward top mounting bracket.

Here's where I started to get a little more concerned. This is the "Oil Tank Filter", and is supposed to have a mesh screen (the filter) on it. I later found what was left of the screen embedded in the sludge in the tank. Note the goo. It's the consistency of gritty jam.

Inspection of the inside of the tank with a flashlight showed a lot of thick black stuff on the bottom.  My regimen to clean the tank was:

1. Load half a pound of pea gravel with solvent (used paint thinner).  Plug orifaces and shake for a while.  Empty out the solvent and gravel.  This gets out most of the remaining oil.

2. Repeat 1 until solvent comes out fairly clean.  There was still evidence of a black material at the bottom of the tank.

3. Load half a pound of pea gravel with hot soapy water.  Plug orifaces and shake for a while.  Empty out the water and gravel.  Still some sludgy stuff.

4. Load half a pound of pea gravel with hot caustic (sodium hydroxide) solution.  Plug orifaces and shake for a while.  empty out the caustic and gravel.  This should attack any thick oil sludge.  After this stage, I could see mostly bare metal inside the tank, but there were patches of what appeared to be rust.

5. Load half a pound of pea gravel with a strong solution of phosphoric acid.  Plug the orifaces and shake for a while.  Empty acid and gravel.  This should eat the rust and provide a protective phosphate coating on the bare metal.

After all this, the inside of the tank looked clean. I did notice while shaking in step 5 that the liquid was leaking out of the tank. After checking my plugs, i realized that the leaks were from some tiny pin holes on the top of the tank. They were probably bridged by rust during cleaning with the other fluids, but the phosphoric acid dissolved the rust. The holes wer barely visible. The picture shows how big I could make them with an awl. I dimpled each of them slightly and soldered over the area to cover them.