Spark plug wires not seated on plugs?

[djork]

This seems like a really stupid question, but how do I know if the spark plug wires are properly seated on the plugs?

The ball end of the plug just seems to rest on a cup in the plug wire conductor. I see a little clip inside the wire end, which looks like something is supposed to slip inside and be firmly connected. But no matter how hard I push it won't go on.

Here's a crude diagram:

https://docs.google.com/drawings/d/1hgzDPVXV0cQKiKWE-j5NI7F9WBxJ_Dxlr4cU0hcDHPg/edit?usp=sharing

[NoSnowJustIce]

Make sure you unscrew the rounded cap off the end of the spark plug. The plug's connector that goes into the plug wire should look threaded, not round. This lets the wire lead grab onto the threads of the plug for a solid connection

[Swanny]

The ball needs to be unscrewed and removed to show the threads. Then you'll feel the boot slide right one

[3vilE30]

Make sure you unscrew the rounded cap off the end of the spark plug. The plug's connector that goes into the plug wire should look threaded, not round. This lets the wire lead grab onto the threads of the plug for a solid connection

The ball needs to be unscrewed and removed to show the threads. Then you'll feel the boot slide right one

They speak the truth!
It a little metal cork on the wire contacts. Just give it a nice twist.

[djork]

Ah ha! Thanks. I haven't seen or heard of this before... but I did notice that only *one* of the old plugs I pulled off was like that. In fact, it was the only one that wasn't horribly corroded from years of a (presumably) poor connection.