Vacuum advance rebuild

[Doug&Deb]

The vacuum advance failed on a distributor I have. I’d like to rebuild it myself but I’m having no luck finding any parts. Since this was a rebuilt unit from Kanter parts must be available somewhere. Distributor is an IAP-4103A-1. I’ve replaced the dizzy but I’d like to have this as a spare.

[Sniper]

rebuild what?  The vacuum advance or the distributor?  I am a little unclear here.

[Doug&Deb]

Sorry, the vacuum advance unit. 

[keithb7]

There’s not much you can rebuild. If the diaphragm has failed;

 

https://www.ebay.ca/itm/384572169771?hash=item598a499e2b:g:IFIAAOSw8UdhrkOs

Edited December 28, 2021 by keithb7

[keithb7]

Check linkage and hook up. Ensure its able to cycle the breaker plate. Try spraying penetrating oil in any holes in the vacuum pot. Get a vacuum on there. Try getting the diaphragm moving again. Might be just rusted up internally. Perhaps you can free it up. Worth a try. Worked for me once on a 1998 4x4 engagement diaphragm that had stopped functioning. 
 

if the rubber seal inside is compromised, a new assembly is likely needed. 

Edited December 28, 2021 by keithb7

[Sniper]

I am surprised no one makes a replacement diaphragm.  Not sure I;d try oil in there, some rubbers fall part with oil on them.

[Doug&Deb]

This is a rebuilt unit. Obviously someone makes parts for them. It’s not holding vacuum so I’m guessing the diaphragm is shot. When I ordered it I had to send them a core. I’ll check that link.

[Art Bailey]

I picked up one of these, because it was cheap and looked close: 

https://www.ebay.com/itm/380474489530

 

 

I opened up my original vac advance, tried sealing the diaphragm with a shmear of gasoline resistant gasket compound, then put it back together using JB Weld. It was a failure. I haven't pursued the new vac advance further, but my plan is to either rivet the old arm onto the new unit, or crack open the new unit, and put the new diaphragm in the old body. The new one doesn't allow you to adjust the tension on the diaphragm, as the old one does. The frustrating part is that the old diaphragm is made of tough cloth of some sort, impregnated with rubber. If you could figure out the right glop to smear on it, you could probably reseal it---there were no tears in the diaphragm, the rubber had simply degraded and become porous.

 

Yes, I know this is a colossal waste of time. This is my idea of fun.

 

In the meantime, I have one from Bernbaum that is NOS and just as leaky as the old one.

Edited December 28, 2021 by ratbailey

[Sniper]

21 minutes ago, ratbailey said:

If you could figure out the right glop to smear on it, you could probably reseal it

Flex seal lol, no idea if that would work

[Art Bailey]

1 hour ago, Sniper said:

Flex seal lol, no idea if that would work

I have a feeling I'm not getting enough clamping pressure or seal around the perimeter of the diaphragm, and that's where it's leaking. The glop I put on was pretty impermeable looking.

 

[Sam Buchanan]

Ok...a question. Other than a small loss of fuel mileage at highway speeds, is there any reason why we can't delete the vacuum advance and drive happily ever after?  

[Sniper]

Vacuum advance tends to keep the plugs clean.

[Bbdakota]

A properly operating Vacuum advance will result in less heat being generated by the engine under light load cruising. I used a vacuum advance from a later model Chrysler and cut the arm off, made a new arm for the flat head distributor and tacked it to the newer vacuum advance. I used vice grips as a heat sink. I only done this because I couldn't find a replacement vacuum advance in time for a event I wanted to attend but it worked fine. I did check how far the vacuum advance advanced the timing and was happy with the results. Sorry, no pictures. 

[DJK]

Had mine rebuilt by Terrill Machine in DeLeon, Texas 254-893-2610

[Bryan G]

10 hours ago, Sniper said:

Flex seal lol, no idea if that would work

I'd try it; I've seen it work on tougher jobs than that. (Though I tend to use Rust Oleum's version.) 

 

I went with a NOS from eBay myself; at least it didn't leak when I got it. I was hoping to see an improvement in gas mileage as mine is pretty dismal, but the difference was marginal at best.

[Dartgame]

Believe Bernbaum used to offer a rebuild service for these....

[Doug&Deb]

I know there are places to get them rebuilt. It’s annoying that I can’t find the parts to do it myself. I doubt that the places that rebuild them manufacture their own components. I’m just being cheap. I only want this for a spare distributor that I may never use. Just venting lol.