You'll be better off in the long term with that plastic float. More and more fuel is getting mixed with alcohols. Alcohols like ethanol, and especially methanol, have an affinity for lead. That includes any solder on floats, and even the lead component alloyed into brass/bronze. The bronze or any soldered joints will eventually dissolve. You probably already found that out the hard way. Commercial methanol distribution systems (such as heat treating atmosphere systems I've worked on) must use all steel or stainless parts, or plastic.
The same thing happens to carburetor floats. Most older carbs that I've worked on in the last several years are getting nothing but plastic replacement floats. Oddly, you can still buy brass. ???
And it's not just the fuel, but many fuel additives like injector cleaners and fuel driers and anti-freezes have alcohols.
Ford was aware of that and was among the first to use plastic lines and fittings for fuel systems. I'm a little surprized your '89 still had brass.