Permanent fix for a corroded Rodac body file air valve -

[goodfellow]

I starting to do some body work on my car and wanted to do some straight line sanding with my ancient Rodac air file. I haven't used this tool in 8 years and after the first five minutes the file just quit. The trigger mechanism just collapsed and I could hear air rushing though the inlet.

I took the trigger apart and to no great surprise found out that the plastic metering valve had disintegrated from years of exposure to oil and moisture.





Here's the valve -- the "O" ring and the plastic valve pieces were just laying in the bottom of the inlet.

A





The spring was still in good shape so I decided to give this thing a permanent fix. The fix is to use a stainless domed screw that fits snugly into valve body inlet



The valve body received new "O" rings.



Here is the air valve body and the plunger



Now to fix this thing I needed to find a stainless domed screw that would fit snugly into the bottom of this valve body --



I found a stainless hex screw that was a perfect fit and would make a nice airtight seal. The hex on top of the screw would make that perfect receiver for the air valve plunger



Insert the spring over the screw and use stainless washers to shim if necessary to set the height of the plunger, and you have a permanent air valve fix. I put everything back together and the file works perfectly.

A

This trick will work with any plunger type of air valve body. The plastic metering valves deteriorate due to oil and water, so stainless screws are a great way to fix these things.

[Uncle Buck]

I need to remember this fix. That is the same air file I have. Maybe mine is the same. It has been a few years since I used mine too.

[jabberwoki]

 Nice, I have a couple of old Rodac air tools.
They're good stuff.

[oldnslo]

+1 on the Rodac. My grinder has seen more than its share of use, and keeps on working despite being purchased in the early 80's

[goodfellow]

These old air sanders/files were direct copies of the original Viking single and dual piston designs. The patent must have run out and everyone jumped into the market. Rodac and CP made excellent copies. The “O” rings came from a standard HF kit, and the stainless button head screw came out of the parts bin. The only “O” ring not replaced was the very small one that’s on the trigger stem Itself. Mine was OK, but if yours is broken, Viking is still in business, and AFAIK they still have the rebuild kits available if you need them.

BTW - the original RODman Air tool Company (RODAC) is long gone. The name lives on with various companies, but you won’t find anything left of the founding company. The surviving RODAC companies won’t be able to supply parts for these older designs.