Power Booster Question- Dual Diaphram

[avejoe]

Anybody replaced a single diaphram booster on a half ton with a dual diaphram booster? If yes, what was involved? Did the brakes work better?

Can power boosters go bad slowly, or do they just stop working?

I have had a really tough time getting my brakes to panic stop. I just had the system checked and there is good pressure to all the wheel cylinders. The brake guy (well recommended) seems to think it's the power booster and recommends a dual diaphram booster.

My booster checks out ok by me as it sinks a little when I turn the truck over and with the motor off it seems to hold pressure.

Thanks!