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Alright, I'm working on the last item on my 2302 that has never worked whatsoever: the vacuum antenna. I finally decided to pull it off and disassemble. I followed some of the previous posts on this topic (a great one by Howard). Thankfully, both leather pieces were intact and reusable. They were dry, and soaked in some Marvel. The washer sandwiched between the two plastic plastic pieces was torn, so it was replaced by a rubber washer. The bottom plastic piece into which the mast screws was cracked, and the threads were stripped. A 1/4"-28 thread insert and whole lot of JBWeld later, and it was back together.

Reassembled everything and the various vacuum lines connected to the switch. The antenna went up without any issue - worked perfectly. Went to bring it down, and nothing. I assumed the base was leaking. Just to test the theory, I put some silicone RTV all around the cap (except for the two air bleed holes on the bottom). I was a little bit surprised to see it still do nothing.

So for those of you who have had success resurrecting your antenna's functionality, what might cause the antenna to be able to go up (we'll say with ease and enthusiasm), but not want to go down at all (even with an assist).

- will mention that I disassembled and cleaned the switch - it was filthy, but did confirm that it directs vacuum as it should.

- perhaps the one variable is the washer used between the two plastic discs is thicker than the original. The original was very thin, more of a papery material. I replaced it with an identically-sized (OD and ID, not thickness) rubber washer. I did sand down the washer to try to get it a little thinner. I didn't suspect this was a problem because I just wonder why it would work one way, but not the other.

- I also haven't replaced the rubber washer at the bottom by the air bleed - it was still pliable and smooth, so I kept it, though I'll still probably look for a replacement washer tomorrow.

Any experience out there troubleshooting these things? Thanks, all!

I am not following exactly what you refer to as the "two air bleed holes" on the bottom. Do you mean the tube where the hose connects or do you actually have a second opening where air can enter. Aside from cosmetic differences between the 47 and 50 antenna, If yours is different in the way it operates would appreciate a photo or two. It sounds at the least like you have a different bottom plug arrangement from what I have on mine. If there is a second air hole and it is too large, perhaps so much vacuum is leaking the piston cannot overcome the initial resistance to move down. Any chance there should be some kind of an adjustment screw arrangement and it is missing?

If your antenna has a bleed, I do not have anything like that on my 47 version. My antenna consists of a tube with a metal casting or possibly a turning which acts as a plug on the bottom of the tube. It has a port where the hose connection tube threads into. That port opening in the plug connects only to an opening or recess in the plug which allows the vacuum into the bottom end of the tube. There is another hole for a threaded bolt or stud in the middle of the plug which is used for mounting to the bottom support brace on the car.

The top end of the antenna -- aside from the external mounting pieces for the fender -- has another plug, bakelite I think, where the upper hose connection enters on the side with a similar port opening arrangement in the plug to allow vacuum into the top end of the tube. There is also a recess where the seal around the mast rod is positioned. A couple of inches above that is another bakelite piece the mast passes thru where the antenna connection is made. I can't remember all the details but there may also be a sort of dirt or debris scraping washer or felt arrangement on that top piece to get rid of any dirt on the mast before it reaches the vacuum seal.

On this antenna air can only enter at the hose connections so with the piston in between the two hose ports, it just moves up or down depending on which side gets vacuum. When a direction is selected the control valve should open the opposite or non vacuum connected side to air to provide the needed air bleed for the other end of the tube so the piston can move the opposite direction. Not sure what any extra air bleed holes would do except leak vacuum away from the piston. If anything, I would have expected the up direction to the one causing a problem because of a leaking seal around the mast rod. No idea what could be happening at the bottom end. Movement is quite rapid on the 47 as a matter of fact so perhaps on later antennas there is an actual bleed as some way to kind of control the speed and that hole is open too much on yours.

If the hoses are disconnected and you move the mast up or down by hand can you feel a decent pressure or suction at the bottom port? You could also rig up a tee connection and a vacuum gauge in the hose going to the bottom end to verify what is actually happening vacuum wise. Gauge should read 0 and move to at least 10-15 and maybe higher when the valve is first opened admitting vacuum to antenna. Should remain somewhat low as the piston moves until it reaches a stop. Unless there is a huge leak the reading should stay reasonably consistent thruout the operation but go to near manifold value when piston reaches the stop. If it never gets close to those numbers I would look for a leak or obstructed tubing. If it goes high and stays high but no movement you might also verify the valve is opening the top side hose to air when you want the mast to go down. If the knob is screwed on too far or something in the mounting bracket is incorrect perhaps the valve is not going full travel when you push knob in to bring the mast down and air can't enter the top end and mast can't move.

Here is what I am working with on the bottom end.

I used compressed air to test the antenna-that way you know if issue is with the antenna or the switch

Hey gang - sorry for the lack of pictures. My setup is a little different ay the bottom. The vacuum portion has the port, and on the bottom, a rubber washer, brass washer, and brass retainer. The vacuum portion goes into the tube, and it is all retained by a cup. The obvious vacuum issue could be between the wall of the tube and the lower vacuum assembly, hence using some silicone RTV to try eliminate that as a possibility.

I did up replacing the lower rubber washer. I took the antenna plunger itself apart again, and I'm going to try using a thinner paper washer between the two plunger halves.

I have a feeling something's still just leaky on the bottom. Here's a video of it behaving as described:youtu.be/hc6AbhfsFHk?si=P22lw_JH6Sc-Skzl

Thanks, all!

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The bottom is completely different from mine so they must have provided something to control the speed the mast goes down by letting a small bit of air in along with the vacuum. I am not familiar with the construction of that assy and without seeing it apart and looking at pieces can only guess as to its operation. I do suspect you are correct that the problem is the new rubber washer. If it opened a larger gap somewhere that gap may be able to allow too much air flow to leak thru so there is not enough vacuum left to pull the piston down.

What is the tan washer like item in the photos at the edge of the antenna? Is that the old washer or the plates you mentioned and does it go back in somewhere or did the rubber washer replace it entirely? Is it maybe a hard phenolic washer?

For grins how about completely blocking the air bleed temporarily by placing a piece of tape over the holes on the outside. Try again to see if mast will lower and if it does then something needs to be revised in that rubber washer assy to limit how much air it is allowing thru the holes. You mentioned 2 plates with a thin something between them. If the plates are hard, the gap allowed by the old thin whatever between the plates could be what is supposed to control the amount of leakage.

I think I may have figured it out. Ultimately, I could really just use new plunger components. The cracks expanded as a result of the insert, and it expanded the diameter of one of the plunger halves, so it just doesn't move as easily in the tunnel.

That said, it came down to the seal in between the two plunger halves. I cut the tan washer initially thinking I'd use that to replace what I found in there, which was some sort of fibrous material. However, I quickly figured out that the whole reason it up well was because the new rubber washer created a great seal on the top side of the plunger, but it didn't create a seal at all for the bottom portion.

I suspect that when these parts were new, and the leather wasn't deformed, the plastic on the plungers wasn't cracked/chipped, the original washer moved from one plunger half to the other, depending where vacuum was being drawn.

So I ended up actually thickening the rubber washer between the plunger halves so that both the top and bottom portions of the canister would be isolated from each other. The two holes at the very bottom of the canister aren't for anything more than allowing water to drain from the canister.

So yeah, with the two halves isolated and the bottom of the canister sealed, I got the antenna to go both directions. It's not perfect, but for the original parts that were pretty beat up, I'll take it!

Here's how it turned out:youtube.com/shorts/aDtAAqLgX28?si=63F7xhaQ0Grq4KB_

Congratulations on finding and fixing the issue and good to know there are no fussy air bleeds to worry about. Not surprised there were leak issues with flat washers as the piston seal though -- was it a stock arrangement or something you did because of not being able to find what was originally there? If stock, must have been another change from the earlier units so maybe they had a different vendor.

The attachment method of sandwiching the seals between flat washers looks the same but 47 used 2 opposed leather cup washers which were an odd size. With the opposed seal lips, one will be sucked tight against the tube no matter which direction is called for so less of a chance for leaking. I could not find anything close to the needed size at all -- either in leather or with rubber brake cylinder cups. For that reason I elected to make my replacement piston with the turned plastic support and the square leather material wrapped around it.

That works OK but since that time I did find several videos on how to make your own leather cup washers in custom sizes. Seems easy enough to do if you can get the thin flat leather material. Not sure of the thickness of the originals but Amazon has some thin stock in small square sizes that should work. Other than material, only other thing needed is time plus ability to make some kind of mold in the correct size to hold the leather while it stretches to shape and dries. Might be something to consider if your flat washers start to give you grief again..

Maybe your antenna will be like vacuum wipers, you'll need to raise and lower your antenna when you're going downhill and have more vacuum.