I don't remember anything being difficult when I did this job, but get a can of silicone spray lube and it will be even easier. I'd probably put the grommet in first because it will be easier to get out if you have difficulty putting the valve in second.  

You cannot get that hard plastic tube off the valve without heating to soften it, but you don't need to as long as you can access the top.  You'll break off the nipple if you pull it without softening. 

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Don Hanson
Sent: Friday, December 02, 2016 10:23 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Grommet install gas tank expansion ?

I'm about to replace the gasket on the top of my right-hand fuel expansion
tank..84 van.  I'm doing this in "camp" .   I'm not keen on trying to get
the expansion tank complety out of the van nor does disconnecting the line to the valve seem like a good thing to try... without damaging the other lines or wrecking the whole tank, so.... I've had the tank loose, the old gasket/grommet...it had nothing left inside to hold it in... The replacement.....?
   In which order should I install that?   Should I put it onto the
roll-over valve (which will still have the line from the gas tank attached) and then the tank, or should I seat the grommet in the expansion tank and then try to push the valve into that?  I see a potential for cracking all
those parts, which would be inconvenient...   The grommets are solar
heating as I type here.   It's about 60f ambient temperature now.   Anyone?