Quote Originally Posted by RidingDonkeys View Post
Great catch. That is it and it is still in the hydraulic path. I need to learn a little more about this one.
Most definitely added by a previous owner. Stock one (on the 6cylinders only) was a Lucas Girling unit, that can still be had through Moss Motors. I think the replacement unit is listed for a Jaguar…

I’ve messed with the Girling stuff extensively and it is very difficult to make them work if you plan to upgrade to front discs at some point. But for an all drum setup they are fine. But an inline booster is the way to go if you want to upgrade and if you ever plan to put disc brakes on the front.

I don’t know anything about the Bendix unit, but I’d be leery of wasting time on it, unless you ever had it working and actually liked the way it performed.