Hydraulic pipe clamp torque spec

Hi, Have a leaking return coupling on my Volvo EC210 CL. I have the replacement clamps but before fitting I would like to know if there is a torque spec for these. Just tightening them by hand out of the machine you can see they distort the internal rubber o-ring to egg-shaped. Possibly this is why it was leaking in the first place. They way I see it, you under tighten and it will leak, over tighten and it’ll leak also. Part number for the coupling is VOE 14531072 Cheers