Starting to work on our new to us FT. Amongst other things chasing down the proverbial air leaks. I had one in the box under the step but I took it apart, recut the 1/4" tubing it and put it back to together and right now it's ok.
Powered it up this afternoon to check some things and heard a hiss behind the dash. Air is leaking out of the top gauge assembly at the large nut. I pulled it apart and put it back together hoping that action alone would fix it. It did not... I can't tell if that is a standard o-ring (and if so what size) or a special style ring for that assembly. The fact that it seats all the way by hand tells me it may need to be replaced as well. And I'm assuming using a pipe tape is not the best long term solution. Any thoughts on where to get a replacement? Thank you.
That is part of a solenoid valve - probably the one that sends air pressure to the Hadleys when you push the horn button. If you can find a suitable sized replacement o-ring for the brass piece that would be the best/cheapest solution.
Or, if there is a part number on the solenoid assembly, you might find a complete new one online. This look like it?
Amazon.com: Hadley Horns H00550C Air Horn Solenoid: Automotive (https://www.amazon.com/Hadley-Horns-H00550C-Horn-Solenoid/dp/B001FMNU86/ref=asc_df_B001FMNU86/?tag=hyprod-20&linkCode=df0&hvadid=312050280935&hvpos=1o1&hvnetw=g&hvrand=17898758298632845572&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1026339&hvtargid=pla-566273360856&psc=1&tag=&ref=&adgrpid=61716360643&hvpone=&hvptwo=&hvadid=312050280935&hvpos=1o1&hvnetw=g&hvrand=17898758298632845572&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1026339&hvtargid=pla-566273360856)
It is best to avoid using thread tape on air system fittings. If you need to seal a threaded pipe connection, better to use a paste sealant.
Permatex makes a good product - available at most auto parts stores.
Amazon.com: Permatex 59235 High Temperature Thread Sealant, 50 ml Tube:... (https://www.amazon.com/gp/product/B000AAJTYS/ref=oh_aui_detailpage_o03_s00?ie=UTF8&tag=foreforums-20&linkCode=as2&camp=1789&creative=390957)
So I called FT and they said they do not have parts that far back and they said if it was there they would either use something they found or put a new solenoid on. They also could not tell me what solenoid it was. Of course, the fact that it was Friday at 4:30 probably had something to do with it...
So I ordered two o-ring kits to have on hand. In the interim, I stopped at Ace to get a stop-gap solution. Of course, you have to hold your o-ring up and try to match it against a picture. I came away with 3 that were close. After opening you can see a big difference more clearly. The bottom one in each picture is the original plastic(?) o-ring/gasket. #53 was too big and moved freely. #11 I did not even try as it is too thick. #54 went on nicely and is either perfect or 95% good. The huge air leak is gone but I still hear a little something if I get my ear down close. I will get the soapy water out to see if it is still that connection or another one that was hiding behind the big air leak sound. Maybe when I get the kits there will be a size that is 100% and I don't have to buy a new $45 solenoid.
You can measure through the plastic bag by a digital caliper on the plastic, and setting to zero and then measure the item inside the bag.