Moneypit.. love that picture.. I used to live in Burnsville, back in the early sixtys when I was REAL little!
My Aunt and Cousins live in Minneapolis... You almost can't see the Foshay tower any more!

well there is another thing that can happen with a bad brake booster, the one on my car just went, and all though i have checked every single vaccum line ( just so i know ) but when you are driving the car or some times just sitting at a light, there is a hissing or a whisteling from under the dash.. kinda like when you have a air leak in a mattress and its not constant but its enough to drive you insane! but i had a mechanic look at it and he said that thats mostly the problem < as there are anew drums shoes pads calipers master cylender and lines!) the only thing that is reused is the booster!
but thats another thing that can go wrong, the seals just gie and the car is always trying to adjust the vaccum, to compensate for the leak!
any ways just another idea!

Joeh Leonard

The old custom cruise wagons uses a powermaster unit. Thats right...no vacuum brake booster. It is electric. Neat idea but i had to change it out in a blizzard FOR THE THIRD TIME. THank goodness for lifetime warranties.

Joeh, that hissing you hear is not your power booster. it's a small vacuum regulator for the automatic transmission that's used to help determine which gear the car is actually in due to vacuum pressure. it's a common leak on 79-91 crown vic and grand marquis as well as town cars. the ford part is now an obsolete number with no dealership carrying the parts anymore. you may be able to seal around the regulator with black silicone or something to that effect, but otherwise you jsut kinda have to deal with it. try moing the shifter around a little up and down in drive or overdrive to see if it get's better/worse

How come I have never seen this vacuum based transmission thingy on my 87. Wierd. Anyways. My speculation is the emergency brake unit. They tend to hiss a lot. I plugged the hose to my unit. No more hiss.

I too would like to find this thingy!

my 77 has a vacuum modulator valve, but no vacuum lines run to this AOD...