Use of the hold off valve?

[Belgium R/T -68]

What will be the effect of not using the "hold off valve" on the brakeline between front and rear?
It's a drum/disc setup and the reason I ask is that the rear brakelines had the wrong dimension on the fittings so if I mount the valve it's keeping oil from going to the rear cylinders. Untill I can replace the lines/fittings I removed the valve.

Per

[John_Kunkel]

If the rear brakes don't lockup prematurely during hard braking there will be no ill effect. The proportioning valve only comes into play when the system pressure is above the "normal" operating range.