Edward
I use a female acme thread to female POL adapter. I screw it
onto my fill valve and them with a male POL to male POL
can hook a barbecue tank up to Westy. No extenda stay needed. What happens is the higher pressure of the barbecue tank (20lb) over comes the low pressure in my Westy tank. I used the extra tank all last year for my
propex and still have not gotten it filled. I did manage to 
fill it once using the tank made for a fork lift and some
adapters but it was really dangerous. 
I was selling the adapters for the fill valve. I may have one 
more if I dig around. I will post a picture of my hose/adapter
later. You should be able to have your local propane rv dealer make one up for under 50.00

Bill

On Sep 10, 2012, at 12:52 PM, Edward Maglott <emaglott3@GMAIL.COM> wrote:

> I have the regular manual bleeder valve and separate fill valve.  I have
> long been looking for a way to hook up a disposable tank to the fill valve
> in the situation that my tank goes empty at a remote location or
> campground.  So I found a good deal on the connector and valve that would
> go on the end of the fill hose at a propane filling station.  Now I'm
> wondering if I made the appropriate fittings to connect the disposable tank
> to that, would the pressure in the tank be enough to open the fill valve on
> the van's tank?  At the filling station they run that pump that pushes the
> propane into the tank.  How much pressure is that?
> 
> I'm not sure if it's legal in all US states to replace propane fittings on
> a RV tank, but you can buy the fittings.
> 
> Edward
> 
> On Mon, Sep 10, 2012 at 9:17 AM, Gabriel Hourtouat <ghourtouat@gmail.com>wrote:
> 
>> Stuart,
>> Where did you get the parts?  In Canada, there are "Rules" against us
>> doing our own work on gas systems and so it is difficult to source the
>> parts...is that also the case in the USA?  I have tried a couple of
>> suppliers and the answer was the same: you are not allowed to do it so
>> I won't sell it to you.
>> Thanks,
>> Gabby
>> 
>> 
>> On Sat, Sep 8, 2012 at 10:51 PM, Stuart MacMillan <stuartmacm@gmail.com>
>> wrote:
>>> On my early auto stop fill valve (which never worked) the bleeder had to
>> be
>>> opened several turns to let it fill.  Quantity of LPG in tank has no
>> effect.
>>> Replace that defective, non-working valve with a standard RV fill valve
>> and
>>> bleed valve, and replace the supply valve and regulator too (if you have
>> the
>>> square regulator).  Total parts cost is about $130 with regulator.  Just
>> did
>>> it on my '85.
>>> 
>>> Stuart
>>> 
>>> 
>>> 
>>> -----Original Message-----
>>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>> Of
>>> Edward Maglott
>>> Sent: Saturday, September 08, 2012 4:53 PM
>>> To: vanagon@GERRY.VANAGON.COM
>>> Subject: Propane tank fill valve
>>> 
>>> So, anybody have any idea how much pressure it takes to open the fill
>> valve
>>> to let the propane in?  Would that pressure be less if the tank were
>> empty?
>>> Thanks,
>>> Edward
>>