| Defroster Door Vacuum Actuator [message #60997] |
Wed, 21 October 2009 17:05  |
Dan Loman
Messages: 1
Registered: May 2009
Location: Howell, MI
Karma: 0
|
Junior Member |
|
|
Hi everyone - I am looking for some help on a '77 Palm Beach
I have been able to fix a multitude of dash heating/cooling nuisances on my '77 Palm Beach, but have gotten down to a 'broken' defroster door vacuum actuator. The reason I believe it to be broken is that I can not build any vaccum on a small circuit (about 6-8 inches of hose)between the actuator (which is inside the underhood heater/blower box) and a factory line splice in the 2 vac feeds that are just outside the box (but still underhood). I have tried each line separately, while blocking off the other - same result, no vacuum at all.
Looking up through the inside heat vent, I was able to see a P/N on the bottom side of the actuator where the 2 vacuum lines attach - the P/N is 3187640. Not sure if this is the assembly P/N or just a component P/N. In any case, I can't find it listed in my Parts Book.
Has anyone replaced this particular actuator? Are there sources for new parts or will this require one reclaimed from a parts coach? If new, does someone have an interchange part number? Finally, what is the easiest way to get the old one out and the new/replacement one in? I think I may have to pull the front (forward) face panel off the underhood blower case and 'move' the heater core to get at this part.
All help is appreciated.
Dan Loman
[Updated on: Wed, 21 October 2009 17:09] Report message to a moderator |
|
|
|
| Re: Defroster Door Vacuum Actuator [message #61056 is a reply to message #60997] |
Wed, 21 October 2009 21:21  |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
|
Senior Member |
|
|
If you're in Michigan, you might try to contact Cinnebar to see if they can help you (they are the most local supplier). They're not cheap, but if anyone has them, it is probably them.
Either of the two Jims should be able to help you if you don't want to deal with Cinnebar, but they certainly are not local to you. You might want to try them first to see if they have any available as they will be more than helpful on how to replace the parts (if it can be done).
Best of luck, I'm not quite ready to tear into my heating/AC system yet. Too many other things to get done first!
George Rudawsky
Chicago, IL
75 Palm Beach
|
|
|
|
| Re: [GMCnet] Defroster Vacuum Actuator [message #61175 is a reply to message #60997] |
Thu, 22 October 2009 09:34 |
Terry Skinner
Messages: 379
Registered: January 2004
Karma: 0
|
Senior Member |
|
|
Have you tried applying vacuum directly to the actuator?? I think you
will find that the actuators are the same, It is the attaching bracket
that is different...........Terry
On Wed, Oct 21, 2009 at 3:05 PM, Dan Loman <dan.loman@gm.com> wrote:
>
>
> Hi everyone - I am looking for some help on a '77 Palm Beach
>
> I have been able to fix a multitude of dash heating/cooling nuisances on my '77 Palm Beach, but have gotten down to a 'broken' defroster door vacuum actuator. The reason I believe it to be broken is that I can not build any vaccum on a small circuit (about 6-8 inches of hose)between the actuator (which is inside the underhood heater/blower box) and a factory line splice in the 2 vac feeds that are just outside the box (but still underhood). I have tried each line separately, while blocking off the other - same result, no vacuum at all.
>
> Looking up through the inside heat vent, I was able to see a P/N on the bottom side of the actuator where the 2 vacuum lines attach - the P/N is 3187640. Not sure if this is the assembly P/N or just a component P/N. In any case, I can't find it listed in my Parts Book.
>
> Has anyone replaced this particular actuator? Are there sources for new parts or will this require one reclaimed from a parts coach? If new, does someone have an interchange part number? Finally, what is the easiest way to get the old one out and the new/replacement one in? I think I may have to pull the front (forward) face panel off the underhood blower case and 'move' the heater core to get at this part.
>
> All help is appreciated.
>
> Dan Loman
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Terry Skinner
Roy. Washington
'76 GMC
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] Defroster Vacuum Actuator [message #61184 is a reply to message #61175] |
Thu, 22 October 2009 17:04 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
|
Senior Member |
|
|
Dan,
I've just finished replacing my entire dash HVAC system, but my '76 is
so much different than your '77 that little of the knowledge I gained is
likely to be of value. But I can tell you from what I learned that the
actuator is probably attached with two 10-32 studs which extend from its
housing on the side toward the actuated arm. That probably means you'll
have to remove the front cover of the HVAC box to reach the two nuts.
And since you're working with the defroster actuator, your
troubleshooting may not be as simple as it seems: The '76 defrost
actuator has TWO vacuum ports, one as expected in the center of the rear
face of the can, another offset 1/2 way to the circumference. If one of
them is open, you'll lose your test vacuum.
HTH,
Ken H.
Terry Skinner wrote:
>> Hi everyone - I am looking for some help on a '77 Palm Beach
>>
>> I have been able to fix a multitude of dash heating/cooling nuisances on my '77 Palm Beach, but have gotten down to a 'broken' defroster door vacuum actuator. The reason I believe it to be broken is that I can not build any vaccum on a small circuit (about 6-8 inches of hose)between the actuator (which is inside the underhood heater/blower box) and a factory line splice in the 2 vac feeds that are just outside the box (but still underhood). I have tried each line separately, while blocking off the other - same result, no vacuum at all...
>> Dan Loman
>> _______________________________________________
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
