Not knowing the center post and method of insulation, there are a number of things you might consider:
1. Is the post sit tightly within in a insulation ring? Might be the insulation ring is warped and too large a inner diameter?
See if you can get a new insulation ring with a smaller diameter/larger outside diameter so the post creates an interference fit when the post is inserted.
2. Maybe the post was undersized at manufacturing. See if you can get a new one (with a larger diameter than the one you have now--not too likely).
3. Do both 1.&2. of the above.
Your goal here is to create an interference fit between post, insulator and insulator outside wall while still being able to insert the assembly within the insulator outside wall.
When you start pulling things apart you can often times destroy the integrity of a slip interference fit (less than .0005").
You might try to take it back to the
shop and they can help you.
In my opinion the manufacturer's are primarily in business to sell you something, not to stand by their products as I was once taught. Hang in there.
