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SOLVED A/C box vacuum pots, rejuvenate rubber innards #2738518
01/31/20 09:17 PM
01/31/20 09:17 PM
Joined: Jan 2003
Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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Michael Ecks  Offline OP
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Columbus, GA
Since I managed to do this I thought I would share the fix.


"Currently working through "restoring" the a/c heater box in my e body and found that a couple of the vacuum pots (actuators - whatever you want to call them) weren't well... actuating when I applied vacuum. Sticky doors are probably part of it, which I'll be cleaning up of course.

But is there a way to rejuvenate the rubber parts, or some kind of conditioner for them so that I am not tearing this thing apart again in 5 years?

I was able to get the push-pull ones to at least move back and forth after removing them from their doors by cleaning the little shafts up with fine sandpaper and putting some silicone grease on them. Just wondering if there is a good product out there to treat the rubber itself."

vacuum pot.jpg
Last edited by Michael Ecks; 02/09/20 08:44 PM.

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741370
02/09/20 08:47 PM
02/09/20 08:47 PM
Joined: Jan 2003
Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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Michael Ecks  Offline OP
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Columbus, GA
All of the pull offs were working, but the push out parts not so much. One not working at all, and the other working but not holding vacuum. You can see the problem in the graphic that the seal was not sealing against the rod. You can also see fine cracks in the seals on my actual vacuum pots, and the rubber had expanded away from the rod as well, leaving a gap.

20200208_125848.jpgunnamed.jpg

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741375
02/09/20 08:55 PM
02/09/20 08:55 PM
Joined: Jan 2003
Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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Michael Ecks  Offline OP
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The best way to rejuvenate old rubber seems to be methyl salicylate or synthetic oil of wintergreen. This guy did a good somewhat scientific comparison of varies methods of softening rubber and methyl salicylate 25% in alcohol came out best. https://www.youtube.com/watch?v=EnGsllKvheQ

I also got recommended a product called rubber renue, which comes from a well known company in the electronics field. It is primarily used to restore rubber pinch rollers in old reel to reel and cassette equipment. I checked the MSDS and it turns out to be 15% methyl salicylate in a bunch of nasty solvents.

71waAUv12IL._SL1500_.jpgAnnotation 2020-02-09 164931.jpg

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741376
02/09/20 08:57 PM
02/09/20 08:57 PM
Joined: Jan 2003
Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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So I found methyl salicylate on amazon and mixed it with strongest rubbing alcohol I could find to make a 25% solution. Then I used fine typed syringes to fill the vacuum pods through the tube. The monoject ones fit perfect, and you can also use the action of the diaphram to pull the fluid in.

20200208_125805.jpg

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741378
02/09/20 09:00 PM
02/09/20 09:00 PM
Joined: Jan 2003
Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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Since you have to turn it over to get good flooding of the vacuum pod, I did one side at a time (about 4 syringes in the large pods and three on the smaller ones) I let them soak for about 12 hours on each side and then emptied (save the fluid) and flushed with straight alcohol.

Just doing this was enough to get both vacuum pods to seal against the rods once I got to the point of soaking that part.

20200208_130617.jpg
Last edited by Michael Ecks; 02/09/20 09:00 PM.

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741379
02/09/20 09:03 PM
02/09/20 09:03 PM
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Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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To help deal with the expansion of the seal I measured the OD of the seal and used slightly smaller o-rings around it to act like a tension spring used in axle seals and engine front seals.

20200208_130919.jpg20200208_131144.jpg

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741381
02/09/20 09:09 PM
02/09/20 09:09 PM
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Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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Finally, I put a fine layer of silicon lubricant on the shaft and then painted the o-rings and the top of the seal with ultra-black rtv. This was to protect the o-rings and also to create a new sealing surface around the top of the seal where it had expanded out. Coating the shaft with silcone lubricant ( I used Sil-Glyde ) prevented the rtv from atatching the rod, leaving a nice clean new round seal around it.

I haven't got everything back up and running in the car yet. But testing the restored A/C box with a vacuum pump, all of the actuators work both ways now and hold vacuum once they reach the end of their travel.

20200208_132143.jpg20200208_132143.jpg

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741384
02/09/20 09:17 PM
02/09/20 09:17 PM
Joined: Jan 2003
Posts: 1,165
Columbus, GA
Michael Ecks Offline OP
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Michael Ecks  Offline OP
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This was all for my 1971 Challenger A/C/heater box that blew out the heater core about 4 years ago. I used Duplicolor Vinyl and Carpet Specialty Coating on the housing and Seymour Stainless Steel Paint on the doors after I bead blasted them. All new gaskets throughout from Detroit Muscle Technologies. All great products.


Can't wait to get it back on the road with heat and defrost again. Depending on how much I get back in taxes I am hoping to put A/C back in the car later this year. (I flushed the evaporator while I had it all apart).

Hope this post helps someone out.

20200201_141644.jpg20200209_111701.jpg

"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Michael Ecks] #2741400
02/09/20 09:49 PM
02/09/20 09:49 PM
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Michigan
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Transman Offline
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Pure genius - thanks.

Going to try this on my son’s Toronado - his one headlight won’t open. Guessing it might be the same issue as this.

Last edited by Transman; 02/10/20 08:19 PM.
Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Transman] #2741514
02/10/20 10:54 AM
02/10/20 10:54 AM
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Houston,Tx.
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Lee446 Offline
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Well done! Thanks for posting this for the rest of us!

Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Lee446] #2741543
02/10/20 12:48 PM
02/10/20 12:48 PM
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north of coder
moparx Offline
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ingenious fix ! up bow
now if i can only remember it if and when i need it !
beer

Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: moparx] #2741714
02/10/20 07:32 PM
02/10/20 07:32 PM
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NJ
EV2RTSE Offline
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Very cool stuff! Will have to tackle this project myself soon.

Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: EV2RTSE] #2744243
02/18/20 12:26 PM
02/18/20 12:26 PM
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Phila. Pa.
Mattax Offline
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Thanks for sharing!
What did you see as the advantage of using alcohol instead of xylene and ethylbenzene for the carrier?

Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Mattax] #2744292
02/18/20 03:00 PM
02/18/20 03:00 PM
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Colorado front range
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BcudaChris Offline
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Thank you for adding to the tech base on Moparts. Please update us from time to time.

I did not get farther than cleaning my vac pots and conditioning the exposed rubber, then using small zip ties in the way you used O-rings. Mine is all in and up and running and performs admirably. Your efforts look like a longer term solution than mine.

Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: BcudaChris] #2744357
02/18/20 05:16 PM
02/18/20 05:16 PM
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mopars4ever Offline
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Yes, I would be curious on how long it lasts. luck

Re: SOLVED A/C box vacuum pots, rejuvenate rubber innards [Re: Mattax] #2744758
02/19/20 09:26 PM
02/19/20 09:26 PM
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Columbus, GA
Michael Ecks Offline OP
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Michael Ecks  Offline OP
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Originally Posted by Mattax
Thanks for sharing!
What did you see as the advantage of using alcohol instead of xylene and ethylbenzene for the carrier?


Mostly I was trying to keep it simple and cheap as possible. Purchasing the pre made rubber renue would have been about 4 times the cost for the same amount, and I didn't want to go buy containers of the xylene etc. Rubbering alcohol, is cheap and has other uses around the house for me.

Ethylbenzene is also toxic when inhaled, but if all you are doing is using a cotton swab to clean pinch rollers in audio equipment probably not a concern. I figure the stronger solvents are probably used in the rubber renue to clean guck off of audio equipment rather quickly while the oil of wintergreen takes care of the softening part of the job.


"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius

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