Valve Housing help needed please!!

Hello,

I've recently had my engine in pieces for general freshening up and since reassembling I've got a leak coming from this part. The rubber is badly cracked so I'm guessing it was sealed with dirt before and I've disturbed it 😒. I have tried googling the part number but apparently it's obsolete 😔
Does anybody know where I can get one? Or an alternative if I can't find one? I tried constructing something from a T piece and a one way valve but I'm not convinced this will do whatever job it needs to…. Any help greatly appreciated!! 

Might be worth  asking  Funkstar 
Look at the  site  sponsors,  classic  vw  , or  maybe  crazyquiff 

I've managed to construct this device… I realise it's not going to win any prizes for being pretty but hopefully it does the job!
Realised I could use the old one-way valve so it's virtually the same as it was I reckon  😬