The drivers side arm rest / grab handle on the front door of my Datsun
280ZX, was quite flappy feeling, due to the breakdown of the hard foam substance inside it...
I removed the arm rest, then lifted up a small section of the vinyil trim ( so as to get access to underneath it ) the squirted in a small amount of "Space Invader " ( expanding foam )...
I had to keep an eye on it as it was drying though...so as to keep it in shape.... but it looks great now...and feels like a new arm rest...nice and tight !
Cheers,
Brian Canham