Haven't done this before, but the following should work:

Warm the end of the nylon hose in a mug of boiled water.
Place the metal fitting in a socket, put both in the oven.
Heat the oven to about 300 degreees or so.

Remove the heated parts with curved pliers.
Push the warmed up end of the nylon tubing onto the warmed up barbed fitting.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022
91 W126 300SE 'Kjetteri' new as of 02/19/2022