Even on the best-sealed of these vintage Polks the drivers will start to go back in after pushing in on the passive. The question is, how fast do they go back in? Do they go ALL the way back in?
When I press and hold the radiator in, the 6.5" move out and then start to come back in. Is there any good materials to seal the drivers back in. I have used a glue in the past, but I don't want to glue all the drivers back in.
Almost all speakers will benefit from installing better capacitors. Sometimes this is done to replace old capacitors that have gone bad, but other times it is done to put in higher quality caps that sound better, whether the originals have gone bad or not. HOWEVER, if, after playing with placement, your speakers are still too boomy, recapping them will NOT solve this.
Finally would these speakers benefit from crossover recap? When I had the radiator out, I could see they had a manufacture date of sept. 1990. I know people have benefited from recaps from speakers from 70's and 80's but not sure if these are "ready" for it.