Marc sierra

iTrader: (1)

I am going to replace the ABS MC on my Sierra as I think it's a bit tired. The MC it has on it now has a valve on the centre outlet pipe going to the rear brakes. I read in the Haynes manual for the Granada that this valve was fitted from 1988 onwards to overcome excessive brake pad wear on the rear brakes.

I have two ABS MC's spare, they both come from a 1990/1991 Granada. But they both don't have this valve fitted on the centre outlet pipe, and I can't remember removing the valve either. Do the later MC's have the valve incorporated in the MC, or should I just take the valve off the current MC and fit it to the new one?