Sanke leaking at liquid out

[jldc]

I need help with a Sanke coupler. There is beer leak at the liquid out. There is no o-ring on the connetcion between the beer nut and the the coupler. On the only exploded view that I can find online it shows a neoprene beer shank washer which is listed as "optional" Should I get one?

L

 

[JRems]

Yes it needs a washer