Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Forum Ambassador
|
If you don't find something suitable, that looks like a very simple project to make a suitable mold and cast the rubber seals in RTV rubber.
Posted on: 2014/9/7 10:31
|
|||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Home away from home
|
Has anyone checked with vacuum antenna rebuilders? Years ago I talked with a rebuilder about rebuilding the antenna on my 1939 Cadillac 60 Special. He could not help me because it used an odd sized chamber. Check with the Cadillac-La Salle Club or see if there are any advertisers in publications. I would bet there is someone out there who does this work and can help.
(o{}o)
Posted on: 2014/9/7 15:07
|
|||
We move toward
And make happen What occupies our mind... (W. Scherer) |
||||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Forum Ambassador
|
This is a continuation of the vacuum antenna repair question and, right or wrong here is what I did on the 47 version. Because it appears this antenna is somewhat different than the 48-50 versions things I did or made may not be applicable to the later units.
I had been trying to figure out how to get the top bakelite piece out to change the seals. In that process a little ring came loose and fell out the end. Upon careful examination and judicious cleaning of the cavity I found the seals. They can be accessed without taking that inner piece out. A word of caution -- if seals are not bad already, they are extremely thin and probably hard & brittle so will likely be destroyed taking the rings off to get them out. I wish I could say the 48-50 version is the same but since the neck appears to be smaller on those units they may be of a different size. Most likely in the same location though. Since the cavity on this antenna is an odd size, nothing I could find in a standard size would fit. I used a homemade hone to enlarge the cavity slightly -- about 1/16" -- so a readily available 5/8 OD seal could be used. Followed that with a 5/8 endmill to make sure the seat was clean and square to the cavity. The overall diameter on this antenna neck is 1" but on the smaller necks, the process may still work as long as there is enough thickness left. Debated about using two seals but decided on a single plus a sealing washer on the outside instead. The washer will work as kind of a scraper before the mast hits the seal. Since the cavity is old and brittle bakelite I didn't want things to be a really tight fit so while the seal is snug, it is not a press fit. Because of that "looseness" I used a length of thinwall tube as a retainer to go between the chrome bezel/washer and top of seal to keep everything locked in place. On the piston end, this cylinder tube is also an odd size. Had planned on using wheel cylinder piston cups but 1 3/16 was too small and 1 1/4 was too large. Had to make my own piston by turning a piece of delrin to size, making a recessed center area and wrapping that area with a leather piston rod seal material. It is snug and sealing well but how long it lasts is unknown -- but for the moment it is working. Here are a few photos. #1 is my 47 version antenna disassembled. #2 is the seal cavity with seals removed. The 4 sided protrusions visible is the cable contact assy the mast slides against. #3 and #4 are the original rings and seals. The order from the top was ring, seal, ring , seal #5 is the 5/8 OD x 5/16 ID seal and washer I used for replacements. #6 is a thin wall tube used as a sort of retainer. Note: in the photo tube is aluminum but decided delrin would be a better choice and is the final. #7 is the replacement piston I am curious if anyone has one working & how fast they move. I used my mightyvac and after a few pumps, the initial resistance was overcome and the thing shot in or out. With a solid vacuum source it should move equally fast so am wondering if perhaps there was a leak or bleed built into the thing to kind of lessen the vacuum for a more controlled movement. EDIT: Interesting photo of the piston. It is a solid cylinder of Delrin with a hole thru the center. Has the circumference wrapped with leather but the camera appears to make it look like a cutaway showing the center as open
Posted on: 2014/9/11 14:29
|
|||
Howard
|
||||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Home away from home
|
Howard...for any of us that are trying to rebuild our antennas, as always, that you post, this is invaluable information. Thank you. I'm sure that as I go through my 49's antenna, this information will be most helpful. If I could just get the stinkin' thing apart....
Posted on: 2014/9/12 20:38
|
|||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Not too shy to talk
|
I was able to make a new leather seal using a leather check book cover I had laying around. Once I cut it to size, I needed it to wrap around the outside diameter of the piston. I accomplished this by soaking the flat seal in water then installed on piston and installed piston assembly into tube and let sit for a few days. The leather conformed nicely around piston. I applied some o-ring grease to piston and to inside of tube, reassembled and tested. The antenna extended fine, but needed help to retract. Turns out the antenna assembly has two bleed valve mechanisms to control speed of extension and retraction. Both are simple rubber discs. One is sandwiched between the piston halves ( see earlier posted photos)and the other is located on the bottom of the tube ( last photo). The disc used in the piston was brittle and would not lay flat and caused excessive leakage. I made a new disc using a bicycle inner tube. I retested and the antenna extended and retracted at a nice even pace.
Posted on: 2014/10/12 19:34
|
|||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Forum Ambassador
|
Very nice. The bleed valves appear to be another difference 48-50 antennas had. The 47 has no sign of anything like that. Maybe something I can rig on mine to slow the action down a bit.
Posted on: 2014/10/12 19:52
|
|||
Howard
|
||||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Not too shy to talk
|
I also cleaned and lubed the control switch.
Now I just need to fix the radio
Posted on: 2014/10/12 19:52
|
|||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Home away from home
|
Harold Rushing is a great guy for rebuilding your radio. He's in this thread:
packardinfo.com/xoops/html/modules/newbb ... um=8&post_id=149997#forumpost149997
Posted on: 2014/10/12 20:13
|
|||
|
Re: Vacuum Antenna
|
||||
---|---|---|---|---|
Quite a regular
|
I would definately agree with aharold arushing being a super radio repair guy, he just finished mine and I love it.
Posted on: 2014/10/13 18:23
|
|||
|