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Evaporator Removal, Other A/C Questions [message #132163] Sun, 26 June 2011 23:40 Go to next message
jcurran is currently offline  jcurran   United States
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Registered: May 2009
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Hi Folks,

A few pieces are missing from my dash air system and I am going to try to rebuild it. I have lots of questions but here are three pressing ones:

Can anyone tell me how many screws are holding the condenser in the A/C housing ? I have removed 4 from the top yet it still won't budge. There is some pretty tough sealant involved, though.

I have a 76 Palm Beach. Looking at the parts book, Figure 26.025 it seems to show the dryer directly attached to the condenser. But there is talk of a "short hose" on the forum and mention of two hoses in the last page of the A/C section in the parts book. Can someone explain ?

Finally, where exactly does the vacuum feeding the A/C vacuum tank come from? The supply line is missing on my system.

Thanks in advance,

Jim


Jim Curran 1976 Palm Beach Alexandria, OH
Re: Evaporator Removal, Other A/C Questions [message #132168 is a reply to message #132163] Mon, 27 June 2011 00:26 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Registered: January 2004
Location: Hebron, Indiana
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Senior Member
The is a hose runs from that tank to the top of the engine for vacuum. Be careful running a new hose if you have not blocked the crossovers on your manifold. If you let the hose lay on top of the crossovers it will melt. You could make yourself a tee and connect it into the brake line vacuum hose which is nearby. On mine I also have a vacuum boost pump so I connected my tee in the line between the vacuum pump and the brake booster. The reduces the tendency for the vacuum operated doors to move under heavy acceleration which is a low vacuum condition.

You have several options so just choose a vacuum source that is convenient to you.



Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: Evaporator Removal, Other A/C Questions [message #132200 is a reply to message #132163] Mon, 27 June 2011 07:44 Go to previous messageGo to next message
fred v is currently offline  fred v   United States
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Registered: April 2006
Location: pensacola, fl.
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Senior Member
jcurran wrote on Sun, 26 June 2011 23:40

Hi Folks,

A few pieces are missing from my dash air system and I am going to try to rebuild it. I have lots of questions but here are three pressing ones:

Can anyone tell me how many screws are holding the condenser in the A/C housing ? I have removed 4 from the top yet it still won't budge. There is some pretty tough sealant involved, though.

I have a 76 Palm Beach. Looking at the parts book, Figure 26.025 it seems to show the dryer directly attached to the condenser. But there is talk of a "short hose" on the forum and mention of two hoses in the last page of the A/C section in the parts book. Can someone explain ?

Finally, where exactly does the vacuum feeding the A/C vacuum tank come from? The supply line is missing on my system.

Thanks in advance,

Jim

i assume you mean the evaporator. i pulled mine out for cleaning and it was hard to get it out. it is a very close fit in the HVAC box top and bottom. try carefully to get a putty knife under it to break it loose from the sticky stuff.


Fred V
'77 Royale RB 455
P'cola, Fl
Re: [GMCnet] Evaporator Removal, Other A/C Questions [message #132202 is a reply to message #132200] Mon, 27 June 2011 08:00 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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Registered: May 2011
Location: Braselton ga
Karma: -74
Senior Member
It makes a difference.  Put a set of 135 volt MOVs across ech hot feed to ground and a couple turns in the power cord, and you'll keep the smoke inside the TV set and the inverters.  MOVs take a small amount of time to clamp, and the added inductance will intergarte the leading edge of the lightning pulse a bit (slow its rise time)  enough to keeop the peak voltage which appears in the coach substantially lower.  When you find tidbits of the MOVs and blast marks in their box, they have dione their job.
 
--johnny


--- On Mon, 6/27/11, fred veenschoten <fredntoni@cox.net> wrote:


From: fred veenschoten <fredntoni@cox.net>
Subject: Re: [GMCnet] Evaporator Removal, Other A/C Questions
To: gmclist@temp.gmcnet.org
Date: Monday, June 27, 2011, 12:44 PM




jcurran wrote on Sun, 26 June 2011 23:40
> Hi Folks,
>
> A few pieces are missing from my dash air system and I am going to try to rebuild it.  I have lots of questions but here are three pressing ones:
>
> Can anyone tell me how many screws are holding the condenser in the A/C housing ?  I have removed 4 from the top yet it still won't budge.  There is some pretty tough sealant involved, though.
>
> I have a 76 Palm Beach.  Looking at the parts book, Figure 26.025 it seems to show the dryer directly attached to the condenser.  But there is talk of a "short hose" on the forum and mention of two hoses in the last page of the A/C section in the parts book.  Can someone explain ?
>
> Finally, where exactly does the vacuum feeding the A/C vacuum tank come from?  The supply line is missing on my system.
>
> Thanks in advance,
>
> Jim

i assume you mean the evaporator. i pulled mine out for cleaning and it was hard to get it out. it is a very close fit in the HVAC box top and bottom. try carefully to get a putty knife under it to break it loose from the sticky stuff.

--
Fred V
'77 Royale RB 455
P'cola, Fl
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: Evaporator Removal, Other A/C Questions [message #132248 is a reply to message #132163] Mon, 27 June 2011 11:38 Go to previous messageGo to next message
idrob is currently offline  idrob   United States
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Location: Central Idaho
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jcurran wrote on Sun, 26 June 2011 21:40

Hi Folks,

A few pieces are missing from my dash air system and I am going to try to rebuild it. I have lots of questions but here are three pressing ones:

Can anyone tell me how many screws are holding the condenser in the A/C housing ? I have removed 4 from the top yet it still won't budge. There is some pretty tough sealant involved, though.

I have a 76 Palm Beach. Looking at the parts book, Figure 26.025 it seems to show the dryer directly attached to the condenser. But there is talk of a "short hose" on the forum and mention of two hoses in the last page of the A/C section in the parts book. Can someone explain ?

Finally, where exactly does the vacuum feeding the A/C vacuum tank come from? The supply line is missing on my system.

Thanks in advance,

Jim


I don't know if it will help, but here are my photos of my evaporator cleaning and repair adventure.

http://www.gmcmhphotos.com/photos/showgallery.php?cat=4048


Rob Allen
former owner of '76 x-PB
Slow [message #132308 is a reply to message #132248] Mon, 27 June 2011 16:16 Go to previous messageGo to next message
bukzin is currently offline  bukzin   France
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Location: North California
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This part of your job is slow going.

We spent a few days just getting all of this apart.



Budget enough time, and band-aids.


Bukzin
1977 Palm Beach
Re: [GMCnet] Evaporator Removal, Other A/C Questions [message #132405 is a reply to message #132248] Tue, 28 June 2011 00:31 Go to previous messageGo to next message
ljdavick is currently offline  ljdavick   United States
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Location: Fremont, CA
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Senior Member
Rob,

How is that fix holding up now that you've removed all that disgusting gunk and re-sealed the doors?

Larry Davick
The Mystery Machine

On Jun 27, 2011, at 9:38 AM, Rob Allen wrote:

> I don't know if it will help, but here are my photos of my evaporator cleaning and repair adventure.
>
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=4048
>
> --
> Rob Allen
> former owner of '76 x-PB
> _______________________________________________
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
Re: [GMCnet] Evaporator Removal, Other A/C Questions [message #132445 is a reply to message #132405] Tue, 28 June 2011 10:42 Go to previous messageGo to next message
idrob is currently offline  idrob   United States
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Location: Central Idaho
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ljdavick wrote on Mon, 27 June 2011 22:31

Rob,

How is that fix holding up now that you've removed all that disgusting gunk and re-sealed the doors?

Larry Davick
The Mystery Machine

On Jun 27, 2011, at 9:38 AM, Rob Allen wrote:

> I don't know if it will help, but here are my photos of my evaporator cleaning and repair adventure.
>
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=4048
>
> --
> Rob Allen
> former owner of '76 x-PB




I sold my GMC to Mitch in Tacoma a couple of years ago. I recharged it with R12a just prior to selling, and have not heard that there has been any problems. I was never really satisfied with the dash AC, but that is a common problem up to 1977's. I will continue to contend that the evaporator is just too small for the job. GM Harrison AC units of that era were generally great, but somehow the GMC Motorhome got left out. They gave the design job to some kid fresh out of engineering school, and forgot to check on him as the senior designers were on summer vacation trips. At least that is my speculation.



Rob Allen
former owner of '76 x-PB
Re: [GMCnet] Evaporator Removal, Other A/C Questions [message #132449 is a reply to message #132405] Tue, 28 June 2011 11:04 Go to previous messageGo to next message
roy1 is currently offline  roy1   United States
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Larry if you haven't done the return air & O.S.A. block modification to your 76 yet I would suggest you put it on your to do list. It doubled the supply air in my 76. I made the return hole even bigger then Zay suggested to be sure I got the maximum benefit.
Roy


Roy Keen Minden,NV 76 X Glenbrook
Re: [GMCnet] Evaporator Removal, Other A/C Questions [message #132563 is a reply to message #132449] Wed, 29 June 2011 01:40 Go to previous message
ljdavick is currently offline  ljdavick   United States
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Roy,

I have Zay's article printed out and dog-eared by now. This is high on my list, but I want to make sure I've got the leak fixed first.

Larry Davick
The Mystery Machine

On Jun 28, 2011, at 9:04 AM, roy@gmcnet.org, keen@gmcnet.org, Minden@gmcnet.org, Nv '76 Glenbrook wrote:

>
>
> Larry if you haven't done the return air & O.S.A. block modification to your 76 yet I would suggest you put it on your to do list. It doubled the supply air in my 76. I made the return hole even bigger then Zay suggested to be sure I got the maximum benefit.
> Roy
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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