RE-SECURING THE RUNNING BOARDS ON A 2007 AIRSTREAM INTERSTATE

A few months ago as we were conducting repairs on our gray water tank system, namely re-plumbing three of its four lines, I noticed another issue in the general vicinity of the tank.

After years of random whisperings and veiled rumors, photographic proof finally emerges:
I have a screw loose.  

Actually I had many screws loose.  The running boards on our 2007 Airstream Interstate were held in place chiefly by a series of structural struts (I'm using the term 'strut' loosely) as shown in the photo above, but they were also stabilized and held securely to the frame by 20 screws installed under each side.  Many of them were well into the process of working themselves free, likely due to the normal vibrations associated with road travel (and this after just 26,000 miles).  

So, you might wonder - why not just tighten them back in place?

They were already too far gone for that.  All were corroded and their hex heads had begun to round to the point where they were not serviceable. 

This is an example of one of those projects that should have been easier than it proved to be.  As it turns out, my husband could not locate replacement hardware-in-kind that was constructed out of stainless steel.  Therefore we had to retrofit.  Here is a series of photos showing the job.

5/16-in-18x1-in stainless steel hex bolt (Lowes Item #396438)
5/16-inch x 1.5-in stainless steel fender washer (Lowes Item # 365174)
I can't find a Lowes URL for the stainless steel split ring washer but our hardware sack says Item # 114197.

Here is an article that discusses the use of stainless steel hardware in high-corrosion environments.  It's written in a marine context but we've found that many of the general principles are useful when selecting RV hardware.

Remove the old screws.  That's a 3/8-in wrench and we also used a socket set to speed the work. 

Action shot!  Overdrill the holes with a 1/4" drill bit.  There was a technique that worked best for this - quick punch with the drill at high speed. 

5/16th inch tap to create new threads that will accept the replacement hardware. It goes through the fiberglass of the running board and proceeds into the metal.  You have to back it out periodically so that it will shed the accumulated metal filings and can proceed unimpeded.  

The install the new hardware using a 1/2-in socket.  If the new threads were installed correctly, you should be able to tighten it quite securely.  The fender washers help to distribute forces across a wider area of fiberglass.

It's hard to get a good pic with only 9 inches of underside clearance.  Here you can see three replacements running down the starboard side with a support in between the two in the background. 

What remains on this project is for me to treat the underside of the running board with some kind of protective coating, perhaps something akin to an elastomeric (I haven't done the research yet on what product would be most effective).  That particular measure might be seen by some as a bit of overkill, but at this point we intend to keep this Interstate long-term, and my husband and I don't want to see breakdown and/or brittleness develop in the underside of the fiberglass over time.