Correct AC compressor

B

bob de kruyff

New member
Mar 21, 2003
7,321
0
0
Hi guys--I haven't posted for a long time due to being super busy and playing with other projects. However, I've been enjoying my 78 GMC and conducted
a fair amount of maintenance on it recently. Over the 4th weekend, I took the coach to one of our reservoirs (lake Roosevelt) for some overdue
camping. The trip went fine until I got stuck in the sand at the camping spot. While trying to get pulled out, my ignition switch crapped out and I
couldn't move it to the start position. I had to force it with a pair of pliers and was able to start it. Then my AC compressor started making a
terrible rattling. Since all of this was happening while I had 2 trucks trying to pull me out of the sand, my only thought was to keep it running and
get to a spot where I could camp. It looks like the AC clutch is coming apart and until I get the compressor out I can't really see what has happened.
I had to cut the belt to stop the rattling and severe vibration even with the AC turned off. The hub of the compressor turns easily by hand. I can
replace the clutch but frankly that compressor is probably at least 30 years old so I plan on replacing the whole thing. I want to stick with a DA6
but I'm wondering what P/N. I assumed it is the same as a 1978 Toronado, but the Interchange manual has different part numbers that do not cross to
the Toronado. I crossed the original 1131953 number and came up with yet another reference that doesn't match any of the others.
Does anyone have a clue what the difference may be between the GMC and Toronado? The pulley diameters all seem to be the same so maybe it is a
difference in pulley offset or hose manifold configuration.
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
 
The pulley diameter.
Toros are smaller.
We have not had great luck with the rebuilds and they all tell us that it
is because they cannot get new critical parts.
We have been using the Sanden conversion with 100% result in last 3 years.

> Hi guys--I haven't posted for a long time due to being super busy and
> playing with other projects. However, I've been enjoying my 78 GMC and
> conducted
> a fair amount of maintenance on it recently. Over the 4th weekend, I took
> the coach to one of our reservoirs (lake Roosevelt) for some overdue
> camping. The trip went fine until I got stuck in the sand at the camping
> spot. While trying to get pulled out, my ignition switch crapped out and I
> couldn't move it to the start position. I had to force it with a pair of
> pliers and was able to start it. Then my AC compressor started making a
> terrible rattling. Since all of this was happening while I had 2 trucks
> trying to pull me out of the sand, my only thought was to keep it running
> and
> get to a spot where I could camp. It looks like the AC clutch is coming
> apart and until I get the compressor out I can't really see what has
> happened.
> I had to cut the belt to stop the rattling and severe vibration even with
> the AC turned off. The hub of the compressor turns easily by hand. I can
> replace the clutch but frankly that compressor is probably at least 30
> years old so I plan on replacing the whole thing. I want to stick with a DA6
> but I'm wondering what P/N. I assumed it is the same as a 1978 Toronado,
> but the Interchange manual has different part numbers that do not cross to
> the Toronado. I crossed the original 1131953 number and came up with yet
> another reference that doesn't match any of the others.
> Does anyone have a clue what the difference may be between the GMC and
> Toronado? The pulley diameters all seem to be the same so maybe it is a
> difference in pulley offset or hose manifold configuration.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
I have a Toro pulley on mine. I got the whole used compressor for free and only needed the clutch. So I replaced the clutch, pulley, and bearing on
mine with the used Toro one. Jim is correct the Toro pulley is slightly smaller.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Thanks for the info guys. I'm amazed at how many different part numbers there are for what appear to be the same compressors. It looks like the
smaller pulley is most common across most of them. A smaller pulley will spin it a bit faster which may be just fine given that we don't rev our
engines that high. It makes me wonder why the GMC had a larger pulley.
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
 
> I have a Toro pulley on mine. I got the whole used compressor for free and only needed the clutch. So I replaced the clutch, pulley, and bearing
> on mine with the used Toro one. Jim is correct the Toro pulley is slightly smaller.

Which must be the reason years ago, that I had to get a different belt when I replaced my A/C clutch (that had a pulley already attached).
--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Manny Tranny etc.
 
Did the 78's come with a different compressor, I thought that the A6 was
the compressor for years even through the 80's.
I ordered through NAPA 10 days ago a clutch assembly for an A6 for my
brothers 69 Cutless.
Napa # 261250

> Thanks for the info guys. I'm amazed at how many different part numbers
> there are for what appear to be the same compressors. It looks like the
> smaller pulley is most common across most of them. A smaller pulley will
> spin it a bit faster which may be just fine given that we don't rev our
> engines that high. It makes me wonder why the GMC had a larger pulley.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
Bruce,
The Harrison A6 AC compressor was used by GM and other manufactures for a lone time including the late 60’s thru the 80’s.

It is the only one that was used by GM in the GMC coach.

JR Wright
GMC Great Laker MHC
GMC Eastern States Charter Member
GMCGL Tech Editor
GMCMI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan

>
> Did the 78's come with a different compressor, I thought that the A6 was
> the compressor for years even through the 80's.
> I ordered through NAPA 10 days ago a clutch assembly for an A6 for my
> brothers 69 Cutless.
> Napa # 261250
>

>
>> Thanks for the info guys. I'm amazed at how many different part numbers
>> there are for what appear to be the same compressors. It looks like the
>> smaller pulley is most common across most of them. A smaller pulley will
>> spin it a bit faster which may be just fine given that we don't rev our
>> engines that high. It makes me wonder why the GMC had a larger pulley.
>> --
>> Bob de Kruyff
>> 78 Eleganza
>> Chandler, AZ
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
It has the capacity to cool a 2 bedroom house. No problem running
additional cooling units in our coaches. Durable, simple. Harrison did a
great job on that one.
Jim Hupy

> Bruce,
> The Harrison A6 AC compressor was used by GM and other manufactures for a
> lone time including the late 60’s thru the 80’s.
>
> It is the only one that was used by GM in the GMC coach.
>
> JR Wright
> GMC Great Laker MHC
> GMC Eastern States Charter Member
> GMCGL Tech Editor
> GMCMI
> 78 GMC Buskirk 30’ Stretch
> 1975 GMC Avion (Under Reconstruction)
> Michigan
>
>

> >
> > Did the 78's come with a different compressor, I thought that the A6 was
> > the compressor for years even through the 80's.
> > I ordered through NAPA 10 days ago a clutch assembly for an A6 for my
> > brothers 69 Cutless.
> > Napa # 261250
> >
> > On Thu, Jul 6, 2017 at 2:26 PM, Bob de Kruyff

> >
> >> Thanks for the info guys. I'm amazed at how many different part numbers
> >> there are for what appear to be the same compressors. It looks like the
> >> smaller pulley is most common across most of them. A smaller pulley will
> >> spin it a bit faster which may be just fine given that we don't rev our
> >> engines that high. It makes me wonder why the GMC had a larger pulley.
> >> --
> >> Bob de Kruyff
> >> 78 Eleganza
> >> Chandler, AZ
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>
> >
> >
> >
> > --
> > Bruce Hart
> > 1976 Palm Beach
> > Milliken, Co
> > GMC=Got More Class
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
John,
Bob stated that he had a DA6 which is also a production run compressor.
Looks to be a little bit more compact than an A6.

> It has the capacity to cool a 2 bedroom house. No problem running
> additional cooling units in our coaches. Durable, simple. Harrison did a
> great job on that one.
> Jim Hupy
>

>
> > Bruce,
> > The Harrison A6 AC compressor was used by GM and other manufactures for a
> > lone time including the late 60’s thru the 80’s.
> >
> > It is the only one that was used by GM in the GMC coach.
> >
> > JR Wright
> > GMC Great Laker MHC
> > GMC Eastern States Charter Member
> > GMCGL Tech Editor
> > GMCMI
> > 78 GMC Buskirk 30’ Stretch
> > 1975 GMC Avion (Under Reconstruction)
> > Michigan
> >
> >

> > >
> > > Did the 78's come with a different compressor, I thought that the A6
> was
> > > the compressor for years even through the 80's.
> > > I ordered through NAPA 10 days ago a clutch assembly for an A6 for my
> > > brothers 69 Cutless.
> > > Napa # 261250
> > >
> > > On Thu, Jul 6, 2017 at 2:26 PM, Bob de Kruyff

> > >
> > >> Thanks for the info guys. I'm amazed at how many different part
> numbers
> > >> there are for what appear to be the same compressors. It looks like
> the
> > >> smaller pulley is most common across most of them. A smaller pulley
> will
> > >> spin it a bit faster which may be just fine given that we don't rev
> our
> > >> engines that high. It makes me wonder why the GMC had a larger pulley.
> > >> --
> > >> Bob de Kruyff
> > >> 78 Eleganza
> > >> Chandler, AZ
> > >>
> > >> _______________________________________________
> > >> GMCnet mailing list
> > >> Unsubscribe or Change List Options:
> > >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >>
> > >
> > >
> > >
> > > --
> > > Bruce Hart
> > > 1976 Palm Beach
> > > Milliken, Co
> > > GMC=Got More Class
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
The larger pulley on the motor home compressor would take less power from the engine, leaving more to move the vehicle.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Right, Terry. The smaller pulley will rotate faster; and, since energy
consumed is proportional to the square of the velocity (rotational speed),
the compressor will consume more power -- and cool better.

Ken H
​.​

> The larger pulley on the motor home compressor would take less power from
> the engine, leaving more to move the vehicle.
> --
>
 
Showoff! ;-)

Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken Henderson
Sent: Friday, July 7, 2017 1:40 PM
To: gmclist
Subject: Re: [GMCnet] Correct AC compressor

Right, Terry. The smaller pulley will rotate faster; and, since energy
consumed is proportional to the square of the velocity (rotational speed),
the compressor will consume more power -- and cool better.

Ken H
​
 
The on line descriptions for these compressors usually state the pulley sizes and most of them appear to be about 5 1/4 diameter. I did find one with
a stated diameter of 6" . I ordered one with a stated size of 5 1/4 and we'll see what it really is. I'm not sure what's on there now frankly.
Regardless, with AZ temperatures well above 110F a little extra cooling capacity won't hurt. I need to stock up on Duracool--is Worthington still the
best source?
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
 
Bob,

I posted this info awhile back:

Tiny URL: http://tinyurl.com/nuhwtb4

Full URL:
http://www.frostycool.com/FrostyCool-r12a-refrigerant-replacement-for-r-12-freon-substitutes-18-oz-equivalent-1-case-12x-cans/

I spoke to a sales rep from this company and he advised that FrostyCool is the SAME gas as Duracool.

Here's the math:

Case of 12 cans: $49.95
UPS Ground to TX: $14.90
Total $64.85

I run this stuff in Double Trouble AND my 1995 Jeep Grand Cherokee, works fine.

Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Bob de Kruyff
Sent: Saturday, July 8, 2017 1:34 AM
To: gmclist
Subject: Re: [GMCnet] Correct AC compressor

The on line descriptions for these compressors usually state the pulley sizes and most of them appear to be about 5 1/4 diameter. I
did find one with
a stated diameter of 6" . I ordered one with a stated size of 5 1/4 and we'll see what it really is. I'm not sure what's on there
now frankly.
Regardless, with AZ temperatures well above 110F a little extra cooling capacity won't hurt. I need to stock up on Duracool--is
Worthington still the
best source?
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
 
You must log in or register to reply here.
Get your shine on at www.cruzingear.co
GMCMI Fall 2026 Rally

Share this page

Share this page
Top Bottom
Back