My car is an EB Fairmont Ghia 5.0L, so I can only describe where the "bits" are located on that vehicle. I think EA - ED is all the same, but beyond that I'm unsure. Into it.
Behind the windscreen washer bottle is a vacuum pump and motor secured by 3 studs. You'll see them just to the left of the bonnet strut. Take the washer bottle out, then the vacuum pump. The leaking elbow on mine was on the black nipple. joining the vacuum pump to the vacuum hose that runs across to the other side of the engine compartment.
On the drivers side, in exactly the same location (but other side of the engine compartment) is the vacuum servo thing that actually pulls the throttle open and closed. It does come out past the brake master cylinder with some effort. It has the same elbow as the vacuum pump motor, and may also leak.
Finally, on the brake pedal under the dash is the brake light switch. This also has a vacuum connection and an elbow. Maybe check this as well?
Also sounds like your bottons need a clean, or the contacts from the steering wheel to the wiring loom. The steering wheel needs to be removed to do this. Do a search of past posts, I have seen detailed descriptions but haven't done this myself.