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.
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0541Medium.jpg)
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0542Medium.jpg)
Here's the valve -- the "O" ring and the plastic valve pieces were just laying in the bottom of the inlet.
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0543Medium.jpg)A
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0544Medium.jpg)
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0545Medium.jpg)
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
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0546Medium.jpg)
The valve body received new "O" rings.
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0547Medium.jpg)
Here is the air valve body and the plunger
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0548Medium.jpg)
Now to fix this thing I needed to find a stainless domed screw that would fit snugly into the bottom of this valve body --
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0549Medium.jpg)
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
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0550Medium.jpg)
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.
(http://i357.photobucket.com/albums/oo18/goodfellow_2004/Jaguar/bodywork_frame/PICT0551Medium.jpg)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.