[455-4+1]

I went through 10 pages of search results but couldn't find the answer ?

I have the body manual but couldn't find it in there either .
2x Queries as follows

Query #1
Under the hood, passenger side near the firewall, there is a vac diaphragm which operates a door / gate. Mine has red stripe vac tube going to it which looks correct. The diaphragm was buggered so managed to get one sent from Franks to New Zealand along with a few other small parts, don't ask me how much !!!!

The diaphragm was a direct replacement for what was on there and seems to work great. Its one direction, (pull only) which seems correct (I think, and hope so !!!)
If that's the case, what acts on the door / gate in the other direction ?
Possibly there is a light spring that is broken somewhere (hopefully not down in the bowels of the heater system !!!).

I manually tested (suck !) the Defrost one under the dash, (yellow tube) and it pulls with vac source, then returns with vac released. Its a single action diaphragm like the other one.

Query #2
The diagrams in the manual show a vac check valve under the hood on the feed line. Mine doesn't appear to have one (a lot of the heater stuff was non functioning as car sat for a long time). Is this a special valve or something - or just a one way check valve (I have a few of them). If so install with vac able to pull from intake, but not release when engine turned off, assume this should be full manifold vac, not ported ?

Here's hoping there isn't a spring missing on the air valve door, or its a simple one to get at !!!

Thanks in advance

[pfilean]

I'm talking from a 1961 but I don't think much changed in the heater for 1963. You may want the heat/AC manuals. Much of what you are looking for should be in there.

My diaphragm for the supply air (near the passenger fender) seems to have a return spring in the diaphragm. Manually pull it and it quickly returns when you release it. I don't know about the check valve as I don't have one either. But what would it hurt to put one in unless the diaphragms wouldn't return when you shut down or change settings.

Mine (and maybe yours) has a valve arrangement to choose which diaphragm is supposed to activate depending where the actuating arms are set. I think only supply air and defrost have them. That little valve is two plates about the size of an American nickel. There are little grooves to determine what works. The plates rub one against the other with no apparent seam between them. They are supposed to have such a flat surface so they seal with vacuum pressure If they get to the point where they do not seal they are near impossible to find and about that hard to get to seal. Good luck. I finally gave up and bought Vintage Air.

[Deadhead]

Been a long time, but if I remember right, there are 2 more of those vacuum motors under the dash on the heater box. One is inside the box. Again, been 10 years since I worked on a ‘63, but I think there were 3 of these buggers.

[455-4+1]

Hey thanks for the replies, I have had a bit of progress

I gave the flapper rod a few liberal coatings of break free and WD40 over about 24 hr, it did move but had no retraction, then i felt a bit of spring back
Carefully working back and forth it now moves freely and returns on it own, albeit a little sticky. So it looks like it has its own spring attached somewhere (probably the 2nd thing to be assembled on the line LOL)
Hopefully a bit more time and lube (its running down the shaft so may take a while) it will be completely free and return every time.

The defrost one under the dash is functioning perfectly surprisingly enough.
There are only 3x vac ports and entry and 2x diaphragm, so hopefully not a hidden one, time will tell

I have put in a one way vac check valve in the feed line. It will be easy to remove if its an issue

Cheers Don

[Rachelsdad]

Sorry to be late to the party, but as I have on my list some vacuum fixups on my '63, I thought I'd chime in.

First, those diaphragms are available brand new (excellent looking and fitting replacements, with the only difference from original being the nuts on the machine screws). I got mine (product #23-5911) from Old Air Products:

https://www.oldairproducts.com/produ...ns-single-port

The '63 (w/o AC) has just two of these: one outside and one inside. As discussed, there is an internal spring, so when vacuum is removed, the door should shut. I can state from experience, however, that this door may not shut all the way (I've had my heater vacuum lines disconnected for over a year while I track down the leaks, and I still blow warm air onto my feet <sigh>). This is likely caused by the pivot rod on the door not being totally free of rust and dirt (top side accessible from outside) and/or a deteriorated seal around the door. There should also be some adjustment available where the shaft from the diaphragm connects to the linkage to the door.

AFAIK, there is no check valve at the back of the carb from where the vacuum is taken. The line connects there, runs through the firewall to the heater control switch. (My dad was the second owner of my '63, in January of '65; I've been through two parts cars, a frame donor, and a '63 GP, none with air, and I have never seen a check valve on any of them).

The replacement valve on the control switch should be GM part #7283558. While this part is widely described as "heater and AC control valve," you will find that it is listed for applications *except* AC, so don't be fooled by the misleading description. There are NOS valves available (Olds Obsolete seems to have one on hand right now, and they show up on eBay at varying times). If you have a leak in the system and it is not a cracked, brittle, old hose, it's likely going to be one or both of the diaphragms or this control, and I would be skeptical about used ones at this point (and I'm not sure about the prospects of rebuilding an old one).

I hope this helps, and I can provide some pics from my car if you need them. The only thing I've got disconnected is the line from behind the carb, which is currently plugged at the T fitting.