You should not have to, I would pinch off the old rubber rubber lines, make sure the master cylinder is kept topped off, replace the wheel cylinders, then the rubber lines one by one, making sure to frequently check the fluid level in the Master cylinder. As long as it does not run low there should not be an issue.
In fact when I purchased my 67 Firebird a few years ago, the rear brake cylinders were bad, the fluid level on the rear reservoir of the Master Cylinder was Empty! After I replaced the wheel cylinders and shoes, I filled and bled the rear brakes and they seem to work fine. I didn't bleed the master cylinder.
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Jeff R
60 Jaguar Mark 2, 3.8L Automatic
67 Sprint Firebird 230 OHC-6 4-Speed A/C
1971 Fiat 130 Coupe 3.2L SOHC V6, ZF 5-speed
78 Catlina Safari, Pontiac 400 powered
77 Astre Formula, 215 Buick V-8 T-5
73 Lemans Safari, 400 4bbl 4-speed
71 Catalina Enforcer, 455 4bbl
05 Dodge Magnum 3.5L SOHC V6
06 Mallet Solstice #024 LS2, Now with a Tremec 6060 6-speed!
2012 F-150 Echo Boost (My local Ford Dealer SUX!!!)
2020 Dodge Charger Scat pack (recovered)
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