Single or dual diaphram. Which one and why

[harris48cars]

Four parts places today and no one could tell me why one was better than the other. Anybody here know the difference. Obviously I'm converting from the stock powermaster. I also want to sell the powermaster, what is a reasonable asking price?
Thanks,
Gary

 

[bmackinnon]

Just get one for an '87 Buick Regal, 5.0L V8.... I recommend spending the few extra bucks and get it from NAPA.... booster/master cylinder ASSEMBLY.... and it's a dual diaphram... smaller booster diameter, so it fits..... :wink:

 

[charlief1]

A dual diphram give a slight edge on braking power. Smaller size will fit better as well.