64 Hisses When Placed in Gear

[rw_removed]

When I started my 64 this morning and put it in gear to back it out of the garage, I heard a "hissing" sound that sounded like it was coming from somewhere in or around the steering column. It is most pronounced in Reverse but I also hear it in the Drive settings. It does not occur in Park or Neutral.

Also, (I think this is just coincidental, but in the interest of full disclosure...) after I backed out and placed the car back in Park, the transmission shift linkage fell out of the shift lever on the steering column in the engine compartment. Apparently the nut holding it in place was not tight and worked it's way off. (Geez, who is the idiot who put this thing together..? Oops, that was me! :banghead) Anyway, I got that back on but still had the hiss.

Any idea what could be hissing? Is there some kind of vacuum hose in the steering column or dash that is activated when the car is put in gear?

 

[boaterbob]

Check the vacuum hoses on the nuetral safety switch and parking brake release

 

[rw_removed]

Thanks

It was a vacuum hose on the neutral safety switch. Also, my wife found the nut/washer that fell off of the shift linkage! So now everything is as it should be.

 

[tbird5866]

My guess is that you don't have a shop manual... If you do not, you should get one.

 

[Gary Tayman]

So it hisses when you put it in gear, but not in neutral or park?

So does mine.

In my case I know for sure it's the parking brake release diaphragm. This, after spending $$$ for a supposedly reputable restoration shop to replace all vacuum hoses and diapragms in the car. They told me the hiss is normal! Stupid . . .

There is a vacuum line that goes to the neutral safety switch. This switch prevents you from starting the car in gear, and is thus electrical, but it also contains a vacuum switch so the parking brake will release when put in gear.

The fact that your shift mechanism fell apart makes me suspicious of the switch itself -- or its alignment. Fix the shift mechanism first. Make sure the vacuum hoses are in place. Then, pull the hose from the parking brake release diaphragm and plug the hose. Does the hissing stop? If so, your diaphragm is leaking. If the hiss is still heard, you have a bad switch or leaky hose.