James,

Clamp the hoses, relace the valve.

Then clamp the hoses at the T's and replace the feeder hoses to the rear
heater.

One heck of a lot less of a mess, and little collant loss, when
performing this task, by clamping them.

I use flat bladed Snap on hose clamper's.

Work good.

Later,

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Terry--
74 Campmobile- (Clementine)
85 GL- (Delilah)
86 BMW 325 ES- (Eva)