it's even more fun when you pull the runflat from one tire, but it into another and assemble it, only find the cracks/dryrot after inflating it, so you pull the runflat out of that one and put it into yet another, then fully assemble it, and have the same thing happen. I still haven't gotten around to putting the runflat back into the original tire and doing the whole thing yet again.
So decided to finish this up last night.
got the runflat back into the original tire, and everything back together.
Stupid thing wouldn't hold air, was leaking air past the rear bead.
Took it apart, inspected everything, made sure everything was clean, and reassembled.
Put air into it again, and again immediately heard it leaking air out the backside.
Got mad at it and gave up.
went out a few minutes ago and hooked the air back up. Tire had been sitting so the backside was up and in the sun.
Maybe it softened up a little from the heat, or just sealed itself up overnight, but now it will hold air no problem. Checked everything with soapy water, no signs of a leak.