Convertible Pneumatic Cylinder Reconstruction

[kgreen]

I have remnants of the thin wall steel actuator cylinders in my 40 Buick convertible.   The tops to my cylinders are missing and the interior of the tube has pitting which would prohibit a good seal for vacuum operation.  Has anybody experience building new cylinders?  I am adventurous enough to try, however, I would sure like to see what a complete cylinder looks like.  For instance, how is the top installed to make an airtight seal?  

[kgreen]

I've been searching for 5.25" OD 0.118 wall thickness DOM tubing to no avail so far.  I only need about 3 feet so small quantity requests for little used product is turning into a difficult proposition.