Raimund,

Although not all your questions can be answered, some of them are in this thread. 

http://www.thesamba.com/vw/forum/viewtopic.php?t=606023&start=0

BenT
sent from my electronic leash

> On Oct 26, 2016, at 1:26 AM, Raimund Feussner <ray@V6BUS.DE> wrote:
> 
> Hello Group!
> 
> 
> After retrofitting the factory ´87 tintop A/C in my ´92 Vanagon in 2004,
> it seems it finally needs new hoses.
> Refrigerant keeps disappearing quicker and quicker...
> 
> I re-used the stock ´87 hoses back then, and also the R12 expansion
> valve (working with R134a since the retrofit).
> For several reasons, I need to drop the evaporator anyway, so I think
> this is my best chance to replace all the old stuff including the
> expansion valve.
> 
> Does anyone have the information about hose lengths, position of
> pressure sensors etc on paper?
> I want to get some quotes from hose suppliers, but don´t want to pull my
> hoses out upfront, just to learn it´s too expensive.
> 
> I would prefer the later style hoses, with the trinary pressure switch
> instead the separate hi/low switches.
> I like to check the A/C myself as much as possible, and might need to
> remove the switch without losing refrigerant.
> 
> Thanks for any help,
> I am struggling to get this information in Germany, as A/C are rare and
> servicing extremely expensive.
> A/C shops keep selling their services as some kind of magic still...
> 
> History:
> In 2009, got the system filled by a shop, nice cooling effect.
> In 2014, system didn´t cool well, I added R134a via Walmart-style
> re-fill kit (12oz can and gauge).
> In 2016, system cooled okay´ish in the beginning, but faded quickly in
> the summer, now not even activating the compressor.
> Bridged the low pressure switch, compressor kicked in, but no effective
> cooling after a few minutes idling. No green leak detection fluid can be
> seen (only visual check at accessible areas without U/V light, no check
> in evap housing or detailed condenser check).
> 
> 
> Regards
> Raimund