1964 Thunderbird vacuum leak at steering column

[Shadrack]

Hey Folks,
Okay, this is weird to me. I installed a new shift lever last night, really improved shifting. BUT wonder if I have broken something else.

HOWEVER - there is a a vacuum leak now. As seen and heard in the video I'm attaching here the noise goes away in park, but changes in pitch (sometimes) when I select gears in PRNDL, buy if I reach down to this line, which plugs into a module on the steering column I can get it to Stop... mostly. What is the module, and how can I replace it/stop the leak lol? I replaced the line to the plastic T but I still have this vacuum line hiss/leak.

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[Rom324]

Well the first thing I would say to you is welcome to the world of Thunderbird‘s. And you are a true hero for taking this car on. I have had many of these cars and they are all a challenge when it comes to things like vacuum and other components. You’re going to have to take your consul side plate off as where all the vacuum accumulates is behind the air-conditioning. Also under your steering column is a vacuum plate that could be where of the problem is originating. You are going to have to isolate the vacuum leak at either of these two places. Mine usually leaked behind the air-conditioner control panel. Again learning how to take the side consul plate off which requires you to drop that piece that includes the ignition switch will get the job done. It’s a little intimidating but don’t let it intimidate you. They’re just screws and everything will come loose. But you have to gain access to those hoses. If you take the driver seat out it will be a lot easier for you to get under there and figure this out. Vacuum is a big part of this car, vacuum door locks, vacuum emergency brake control, vacuum air-conditioner, Vacuum trunk release if so equipped etc. etc. The seat comes out with four bolts underneath the car. Trust me when I tell you take the seat out and you can lay down and get under the dash to see where the leaks will be. Once solved you’ll have a beautiful running car. Good luck , We have all been there.

 

[Rom324]

Well the first thing I would say to you is welcome to the world of Thunderbird‘s. And you are a true hero for taking this car on. I have had many of these cars and they are all a challenge when it comes to things like vacuum and other components. You’re going to have to take your consul side plate off as where all the vacuum accumulates is behind the air-conditioning. Also under your steering column is a vacuum plate that could be where of the problem is originating. You are going to have to isolate the vacuum leak at either of these two places. Mine usually leaked behind the air-conditioner control panel. Again learning how to take the side consul plate off which requires you to drop that piece that includes the ignition switch will get the job done. It’s a little intimidating but don’t let it intimidate you. They’re just screws and everything will come loose. But you have to gain access to those hoses. If you take the driver seat out it will be a lot easier for you to get under there and figure this out. Vacuum is a big part of this car, vacuum door locks, vacuum emergency brake control, vacuum air-conditioner, Vacuum trunk release if so equipped etc. etc. The seat comes out with four bolts underneath the car. Trust me when I tell you take the seat out and you can lay down and get under the dash to see where the leaks will be. Once solved you’ll have a beautiful running car. Good luck , We have all been there.

If you hear a hissing then you know you have a problem. Keep working at it until the hissing goes away. I have found that cracked hoses because of age need to be replaced. Buy yourself some vacuum hosing either 5/16 or 3/8 whatever is the case and you will have a much better success rate. Vacuum hose is cheap and start replacing those vacuum lines. They keep cracking on me and I have had to replace all of them. Just a thought

 

[Shadrack]

Thank you @Rom324 thank you! I know I have a ton a tracing to do.

I'm just wondering if this is some sort of modulator or part of the shift process as it goes to a part on top the bottom of column area with it would seem two leads going out. I did replace the vacuum line going to it and it still seems to leak when I shift between gears - so this tells me it has to be, well MAY BE a bad part...just not sure what this part does lmao. @Rom324 I love this old beast, I'll never give up! 🙂

 

[Rom324]

Thank you @Rom324 thank you! I know I have a ton a tracing to do.

I'm just wondering if this is some sort of modulator or part of the shift process as it goes to a part on top the bottom of column area with it would seem two leads going out. I did replace the vacuum line going to it and it still seems to leak when I shift between gears - so this tells me it has to be, well MAY BE a bad part...just not sure what this part does lmao. @Rom324 I love this old beast, I'll never give up! 🙂

You shouldn’t have any hissing or leaking. That’s a hose problem. If it’s under the column you’re going to need to trace it from the emergency brake and maybe isolate that and plug it off and trace it back to the Vacuum can under the engine compartment. Make sure that’s solid no leaks from your under dash to the engine compartment. It is routed to the passenger side floor to the engine compartment.

 

[Shadrack]

You shouldn’t have any hissing or leaking. That’s a hose problem. If it’s under the column you’re going to need to trace it from the emergency brake and maybe isolate that and plug it off and trace it back to the Vacuum can under the engine compartment. Make sure that’s solid no leaks from your under dash to the engine compartment. It is routed to the passenger side floor to the engine compartment.

@Rom324 thank you! So you think it has something to do with the brake? Wonder how that is tied in with the shifting of prndl

 

[tbirdr75]

@Rom324 thank you! So you think it has something to do with the brake? Wonder how that is tied in with the shifting of prndl

If the 64 is like the 66 [I think it is] then there is a unit in the steering column that switches vacuum to the brake release when you shift out of Park.

 

[Shadrack]

If the 64 is like the 66 [I think it is] then there is a unit in the steering column that switches vacuum to the brake release when you shift out of Park.

Makes sense, I think mine is malfunctioning, is there a replacement part or a good bypass? Thanks!

 

[inspector]

The park brake release mechanism has a vacuum diaphragm on it which automatically releases the emergency brake when you put the car in gear. If the diaphragm has a hole in it it will hiss when you put the car in gear. There is also a valve mechanism at the base of the steering column which allows vacuum to the diaphragm when the car is put in gear. Its a real pain trying to replace this diaphragm if you can find one . You can block the line off at the steering column and convert the brake release to manual.

 

[didi]

Hey Folks,
Okay, this is weird to me. I installed a new shift lever last night, really improved shifting. BUT wonder if I have broken something else.

HOWEVER - there is a a vacuum leak now. As seen and heard in the video I'm attaching here the noise goes away in park, but changes in pitch (sometimes) when I select gears in PRNDL, buy if I reach down to this line, which plugs into a module on the steering column I can get it to Stop... mostly. What is the module, and how can I replace it/stop the leak lol? I replaced the line to the plastic T but I still have this vacuum line hiss/leak.

that white plastic thing is the neutral safety switch and there a 2 little thingies on there that the vacuum lines go on,

 

[Shadrack]

Excellent, thank you, everyone! Since my switch has been bypassed I will just ignore it. I will also plug up the vacuum line as well. What do you all find to be the most effective ways to plug vacuum lines? I have seen bolts and screws put in them - just want to do it halfway right. I guess I could always get an elbow and delete the T - not sure though - would rather cap off the line I think.

 

[Rom324]

I buy the tees elbows and straight fittings in a box. I think I bought mine at Napa. You can then use a rubber plug. Seems to work the best for blocking off vacuum lines

 

[Rom324]

If you want the real education on vacuum for your Thunderbird take the front seat out and your side consul panel off. Get a good light and crawl under there and start looking at all the vacuum lines that attach to the air-conditioning and miscellaneous other vacuum hoses running under there. Start looking for cracked hoses because they’re old and many of them will just start to deteriorate. Good idea to replace much of this. Once you look at it and study it a while it’s not so intimidating. But it is a big Achilles’ heel for these cars regarding vacuum.

 

[Rom324]

Before I replaced all my hoses under there, it seemed like every day I was hearing a hiss from another hose that cracked. They crack where you attach them even cutting them back an inch or so. The entire hose is old and therefore will continue to do this. Also your vacuum door locks manifold under the passenger compartment dash and behind the safety convenience panel in the middle of the dash is another sore spot. Check these as well

 

[Rom324]

If your car does not have air-conditioning or the safety Convenience panel with the door ajar light low fuel light and vacuum door lock option You will have fewer problems with vacuum leaks. Mine is a loaded car with even vacuum trunk release and cruise control. A vacuum menagerie. Lol

 

[Rom324]

One good thing is that if you are hearing hissing under the dash then your vacuum can at the firewall in the engine compartment and the line running to the inside of your car is functioning well. At least that’s good. LOL

 

[Rom324]

I found this diagram of the vacuum manifold under the passenger side dashboard. This will give you an idea of what it takes to do vacuum door locks. They work well if your manifold is good. I would just keep them original. The electric could be a lot more troubleAnd expense to do

 

[Shadrack]

I found this diagram of the vacuum manifold under the passenger side dashboard. This will give you an idea of what it takes to do vacuum door locks. They work well if your manifold is good. I would just keep them original. The electric could be a lot more troubleAnd expense to do

THANK YOU! I appreciate all the info, I really do! I think I will take a look at the locks when I get the new radiator and fan installed. I am working on wiring a relay box and I am considering also changing the fuse box over to blade fuses. I am not ready to tear into that quite yet though - want to get some time behind a soldering iron a bit more before redoing the factory box.

 

[JDKlatt]

I appreciate all the patience and attention to detail here. I have the same hose failure. I could guess buy the effect of the gear lever that mine is the brake release. I even have a supply of the correct size hose. I cannot locate the connection on the steering column after spending a lot of time with my head under there with a light and a mirror. I found an image online of a vaccuum line coupler with the shape of the column on one side and the nipples together on the body of the the thing. I thought I would recognize that when I saw it but so far no cigar. I see after further searching that I am looking for the neutral safety switch. Is it necessary to pull if off the car to put the hose on it? thanks for your patience.

 

[Mike Tbird]

Hey Folks,
Okay, this is weird to me. I installed a new shift lever last night, really improved shifting. BUT wonder if I have broken something else.

HOWEVER - there is a a vacuum leak now. As seen and heard in the video I'm attaching here the noise goes away in park, but changes in pitch (sometimes) when I select gears in PRNDL, buy if I reach down to this line, which plugs into a module on the steering column I can get it to Stop... mostly. What is the module, and how can I replace it/stop the leak lol? I replaced the line to the plastic T but I still have this vacuum line hiss/leak.

Not sure on a 64 but my 66 has a vacuum switch tied to the parking brake. When you out the car in drive, it disconnects the parking brake. Its tied into the gear selecting linkage under the dash. If it's defective or out of adjustment, it can leak. Used up until more modern Crown Vic's.