Spark plug connectors keep coming loose

Hello,
"On my 1997 A4 Avant with a 1.9 TDI 81kw (AFN) engine, the glow plug connectors keep coming loose."
Due to age, the rubber casing has detached from all 4 connectors.
Is there now a solution for how to replace the connectors individually?
Is there a way to securely attach the connectors to the spark plugs, or to enlarge the contact area on the spark plugs using crimp ferrules?
Greetings, Denis.

Have you ever tried using a water pump pliers to slightly narrow the connector all around?
There's not much you can mess up if you're planning to replace them anyway.
Practice makes perfect.

No, I haven't tried that yet, but since it's plastic, I assume that it will break, and then I won't have a plug at all .

I'm not going to bother renewing it, because the way things are now, this isn't meant to be a permanent solution. I'll have to check on it every two days and make sure all the plugs are still connected. "Where the front and back are usually completely gone."

Look over there.
/viewtopic.php?t=22595&highlight=443+971+994
or there
/viewtopic.php?t=22531&highlight=443+971+994
hg
Herbert.