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[GMCnet] v-twin air compressor has low pressure [message #262320] Fri, 19 September 2014 12:58 Go to next message
Bob Wright is currently offline  Bob Wright   United States
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Does anyone know a source for manual or instructions for setting up the air
ride compressor that is in a 76 coach with the blue triangle cover? Mine
runs but the pressure is so low that I can only conclude that it has a leak
internally or is out of sync between the two cylinders. I removed the hose
to the tank and can put my finger over it without the air blowing past. Do
the two cylinders need to have the pulleys in a certain position when
setting up the belt? I recently bought this coach and it has never been
able to raise the air bags. I use a bicycle pump at the small tank beside
the pump.

Any advice or manual/instructions online welcome.

Bob
Victoria. B.C.
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Re: [GMCnet] v-twin air compressor has low pressure [message #262322 is a reply to message #262320] Fri, 19 September 2014 14:00 Go to previous messageGo to next message
George Beckman is currently offline  George Beckman   United States
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Location: Colfax, CA
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Bob Wright wrote on Fri, 19 September 2014 10:58
Does anyone know a source for manual or instructions for setting up the air
ride compressor that is in a 76 coach with the blue triangle cover? Mine
runs but the pressure is so low that I can only conclude that it has a leak
internally or is out of sync between the two cylinders. I removed the hose
to the tank and can put my finger over it without the air blowing past. Do
the two cylinders need to have the pulleys in a certain position when
setting up the belt? I recently bought this coach and it has never been
able to raise the air bags. I use a bicycle pump at the small tank beside
the pump.

Any advice or manual/instructions online welcome.

Bob
Victoria. B.C.
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Bob,

I am not expert, but I doubt the cylinders are out of phase. They do have to be in phase but I doubt cog belt slipped. I believe the GMC manual shows how to rebuild. JimK has rebuild kits. I had tried to rebuild the valves (JR Slaten Valves fixed that) on my '74 with minimal luck so decided to buy a rebuilt from JimK, but probably could have saved myself some money without too much work.





'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
Re: [GMCnet] v-twin air compressor has low pressure [message #262324 is a reply to message #262320] Fri, 19 September 2014 14:32 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
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Registered: August 2005
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Senior Member
On Fri, Sep 19, 2014 at 10:58 AM, Bob Wright wrote:

> Does anyone know a source for manual or instructions for setting up the air
> ride compressor that is in a 76 coach with the blue triangle cover? Mine
> runs but the pressure is so low that I can only conclude that it has a leak
> internally or is out of sync between the two cylinders. I removed the hose
> to the tank and can put my finger over it without the air blowing past. Do
> the two cylinders need to have the pulleys in a certain position when
> setting up the belt? I recently bought this coach and it has never been
> able to raise the air bags. I use a bicycle pump at the small tank beside
> the pump.
>
> Any advice or manual/instructions online welcome.
>

​here is some old info
http://gmcmotorhome.info/leveling.html

erf​


>
> Bob
> Victoria. B.C.
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--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
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Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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Re: [GMCnet] v-twin air compressor has low pressure [message #262329 is a reply to message #262320] Fri, 19 September 2014 15:57 Go to previous messageGo to next message
lqqkatjon is currently offline  lqqkatjon   United States
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from what I can tell, it does not matter what phase the cylinders are in. I recently replaced that dana compressor (2 cylineder with blue triangle cover), with what I feel is a big upgrade, viair compressor. cost me about $240 total.

I found the squealing issue with that original compressor was the electrical motor, so I pulled off the belt, and pulled apart the motor, oiled and reassembled the unit. It seems to pump air, and I will probably get a check valve, and give it to a friend for onboard air for his jeep.

when I reinstalled the belt, I just tossed it on, and it seemed to pump air just fine, I did not index the piston rotation at all.



Jon Roche 75 palm beach EBL EFI, manny headers, Micro Level, rebuilt most of coach now. St. Cloud, MN http://lqqkatjon.blogspot.com/
Re: [GMCnet] v-twin air compressor has low pressure [message #262333 is a reply to message #262320] Fri, 19 September 2014 16:41 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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The pistons need to be times 180 degrees apart on the Dana. That is why they used hte cog belt so it can not jump out of time.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] v-twin air compressor has low pressure [message #262344 is a reply to message #262333] Fri, 19 September 2014 20:01 Go to previous messageGo to next message
Bob Wright is currently offline  Bob Wright   United States
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Thanks everyone. I have already set the pistons at 180 but there is still
not enough pressure to raise the airbags. I guess I am in for a rebuild.
I pulled the tops off and the insides look clean but I suspect the valve
or 0-rings are tired.

On Fri, Sep 19, 2014 at 2:41 PM, Ken Burton wrote:

> The pistons need to be times 180 degrees apart on the Dana. That is why
> they used hte cog belt so it can not jump out of time.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
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Re: [GMCnet] v-twin air compressor has low pressure [message #262345 is a reply to message #262329] Fri, 19 September 2014 20:12 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
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Actually is does make a difference. They should be opposite -- that is one is at the top of the compression stroke while the other is at the bottom. Otherwise the motor may be working against two compressions at the same time for part of the rotation and then on intake the rest of the time. It will run smoother and draw less current if they are phased properly.

Emery Stora
77 Kingsley
Frederick, CO

On Sep 19, 2014, at 3:57 PM, Jon Roche wrote:

> from what I can tell, it does not matter what phase the cylinders are in. I recently replaced that dana compressor (2 cylinder with blue triangle
> cover), with what I feel is a big upgrade, viair compressor. cost me about $240 total.
>
> I found the squealing issue with that original compressor was the electrical motor, so I pulled off the belt, and pulled apart the motor, oiled and
> reassembled the unit. It seems to pump air, and I will probably get a check valve, and give it to a friend for onboard air for his jeep.
>
> when I reinstalled the belt, I just tossed it on, and it seemed to pump air just fine, I did not index the piston rotation at all.
>
>
> --
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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Re: [GMCnet] v-twin air compressor has low pressure [message #262347 is a reply to message #262320] Fri, 19 September 2014 20:56 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
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Bob Wright wrote on Fri, 19 September 2014 12:58
...Any advice or manual/instructions online welcome. ...
The kit comes with instructions.

http://www.appliedgmc.com/prod.itml/icOid/861
Re: [GMCnet] v-twin air compressor has low pressure [message #262350 is a reply to message #262345] Fri, 19 September 2014 21:29 Go to previous messageGo to next message
Bob Wright is currently offline  Bob Wright   United States
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And isn't the intent that one feeds the other at low pressure and the
second one feeds the system with higher?

On Fri, Sep 19, 2014 at 6:12 PM, Emery Stora wrote:

> Actually is does make a difference. They should be opposite -- that is
> one is at the top of the compression stroke while the other is at the
> bottom. Otherwise the motor may be working against two compressions at the
> same time for part of the rotation and then on intake the rest of the
> time. It will run smoother and draw less current if they are phased
> properly.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>
> On Sep 19, 2014, at 3:57 PM, Jon Roche wrote:
>
>> from what I can tell, it does not matter what phase the cylinders are
> in. I recently replaced that dana compressor (2 cylinder with blue
> triangle
>> cover), with what I feel is a big upgrade, viair compressor. cost me
> about $240 total.
>>
>> I found the squealing issue with that original compressor was the
> electrical motor, so I pulled off the belt, and pulled apart the motor,
> oiled and
>> reassembled the unit. It seems to pump air, and I will probably get a
> check valve, and give it to a friend for onboard air for his jeep.
>>
>> when I reinstalled the belt, I just tossed it on, and it seemed to pump
> air just fine, I did not index the piston rotation at all.
>>
>>
>> --
>> 75 palm beach
>> St. Cloud, MN
>> http://lqqkatjon.blogspot.com/
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Re: [GMCnet] v-twin air compressor has low pressure [message #262412 is a reply to message #262350] Sat, 20 September 2014 17:50 Go to previous messageGo to next message
Bruce Hart is currently offline  Bruce Hart   United States
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Location: La Grange, Wyoming
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Senior Member
Bob,
Be sure the air inlet is not clogged, the filtering material in the
original compressors will break down and crumble into a sticky mess.

On Fri, Sep 19, 2014 at 8:29 PM, Bob Wright wrote:

> And isn't the intent that one feeds the other at low pressure and the
> second one feeds the system with higher?
>
> On Fri, Sep 19, 2014 at 6:12 PM, Emery Stora wrote:
>
>> Actually is does make a difference. They should be opposite -- that is
>> one is at the top of the compression stroke while the other is at the
>> bottom. Otherwise the motor may be working against two compressions at
> the
>> same time for part of the rotation and then on intake the rest of the
>> time. It will run smoother and draw less current if they are phased
>> properly.
>>
>> Emery Stora
>> 77 Kingsley
>> Frederick, CO
>>
>> On Sep 19, 2014, at 3:57 PM, Jon Roche wrote:
>>
>>> from what I can tell, it does not matter what phase the cylinders are
>> in. I recently replaced that dana compressor (2 cylinder with blue
>> triangle
>>> cover), with what I feel is a big upgrade, viair compressor. cost me
>> about $240 total.
>>>
>>> I found the squealing issue with that original compressor was the
>> electrical motor, so I pulled off the belt, and pulled apart the motor,
>> oiled and
>>> reassembled the unit. It seems to pump air, and I will probably get a
>> check valve, and give it to a friend for onboard air for his jeep.
>>>
>>> when I reinstalled the belt, I just tossed it on, and it seemed to pump
>> air just fine, I did not index the piston rotation at all.
>>>
>>>
>>> --
>>> 75 palm beach
>>> St. Cloud, MN
>>> http://lqqkatjon.blogspot.com/
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>> _______________________________________________
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>>
> _______________________________________________
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--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming
Re: [GMCnet] v-twin air compressor has low pressure [message #262433 is a reply to message #262412] Sat, 20 September 2014 21:53 Go to previous messageGo to next message
Bob Wright is currently offline  Bob Wright   United States
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Registered: August 2014
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Bruce: Thanks. That is one thing I had not checked.

On Sat, Sep 20, 2014 at 3:50 PM, Bruce Hart wrote:

> Bob,
> Be sure the air inlet is not clogged, the filtering material in the
> original compressors will break down and crumble into a sticky mess.
>
> On Fri, Sep 19, 2014 at 8:29 PM, Bob Wright wrote:
>
>> And isn't the intent that one feeds the other at low pressure and the
>> second one feeds the system with higher?
>>
>> On Fri, Sep 19, 2014 at 6:12 PM, Emery Stora wrote:
>>
>>> Actually is does make a difference. They should be opposite -- that is
>>> one is at the top of the compression stroke while the other is at the
>>> bottom. Otherwise the motor may be working against two compressions at
>> the
>>> same time for part of the rotation and then on intake the rest of the
>>> time. It will run smoother and draw less current if they are phased
>>> properly.
>>>
>>> Emery Stora
>>> 77 Kingsley
>>> Frederick, CO
>>>
>>> On Sep 19, 2014, at 3:57 PM, Jon Roche wrote:
>>>
>>>> from what I can tell, it does not matter what phase the cylinders
> are
>>> in. I recently replaced that dana compressor (2 cylinder with blue
>>> triangle
>>>> cover), with what I feel is a big upgrade, viair compressor. cost
> me
>>> about $240 total.
>>>>
>>>> I found the squealing issue with that original compressor was the
>>> electrical motor, so I pulled off the belt, and pulled apart the
> motor,
>>> oiled and
>>>> reassembled the unit. It seems to pump air, and I will probably get
> a
>>> check valve, and give it to a friend for onboard air for his jeep.
>>>>
>>>> when I reinstalled the belt, I just tossed it on, and it seemed to
> pump
>>> air just fine, I did not index the piston rotation at all.
>>>>
>>>>
>>>> --
>>>> 75 palm beach
>>>> St. Cloud, MN
>>>> http://lqqkatjon.blogspot.com/
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>>
>>> _______________________________________________
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>>>
>> _______________________________________________
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>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
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Re: [GMCnet] v-twin air compressor has low pressure [message #262462 is a reply to message #262320] Sun, 21 September 2014 09:10 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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Location: Braselton ga
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Senior Member
This weekend's project is installing a Viair 450 series compressor in my coach. The Firestone one which came in it died, and I 'got by' whith a Campbell - Hausfield one to get to Bean Station, where I simply pumped the bags and turned the petcocks. Viair wired in and mounted in a couple or three hours, now I find there's a major leak someplace. So, today's project is find the leak.

--johnny


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: [GMCnet] v-twin air compressor has low pressure [message #262463 is a reply to message #262462] Sun, 21 September 2014 09:19 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
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Senior Member
On Sunday, September 21, 2014, Johnny Bridges wrote:

> This weekend's project is installing a Viair 450 series compressor in my
> coach. The Firestone one which came in it died, and I 'got by' whith a
> Campbell - Hausfield one to get to Bean Station, where I simply pumped the
> bags and turned the petcocks. Viair wired in and mounted in a couple or
> three hours, now I find there's a major leak someplace.




> So, today's project is find the leak.
>
> Good luck, this is what I did

http://www.gmcmhphotos.com/photos/flor-gmc-s-in-florence-or/p40827-wireless-air-block-diagram-by-gmces-bryon.html

Erf

--johnny
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
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--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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Re: [GMCnet] v-twin air compressor has low pressure [message #262499 is a reply to message #262320] Sun, 21 September 2014 18:01 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
Well, lessee... electric valves, bluetooth or equal stuff, learning curve, pressure 'sted of height. Several hunnert bux, several hours.

Versus five minutes to trace the hiss, $1.90 for a pack of four Schrader valve inners, $2 for a valve stem tool which I needed anyway. Like the ol' maid at the soiree 'I think I'll dance with the one what brung me'. Only anticipated upgrade is Sulivan's setup when the stock bags go Dixie on me.

I used the time saved to finish up the crusing control on the Kia. All in all, a positive afternoon. Next up - howcome the toad truck suddenly gave outa sparks. Ignition switch is the current culprit. I have a couple spare toggles mounted in the toy, the temptation is to simply light the fire with one of them.

--johnny


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: [GMCnet] v-twin air compressor has low pressure [message #262502 is a reply to message #262499] Sun, 21 September 2014 20:11 Go to previous message
Mr ERFisher is currently offline  Mr ERFisher   United States
Messages: 7117
Registered: August 2005
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Senior Member
On Sunday, September 21, 2014, Johnny Bridges wrote:

> Well, lessee... electric valves, bluetooth or equal stuff, learning curve,
> pressure 'sted of height. Several hunnert bux, several hours.
>
> Versus five minutes to trace the hiss, $1.90 for a pack of four Schrader
> valve inners, $2 for a valve stem tool which I needed anyway. Like the ol'
> maid at the soiree 'I think I'll dance with the one what brung me'. Only
> anticipated upgrade is Sulivan's setup when the stock bags go Dixie on me.


Good move
Good luck
Nice to have a place to go

Erf

>
> I used the time saved to finish up the crusing control on the Kia. All in
> all, a positive afternoon. Next up - howcome the toad truck suddenly gave
> outa sparks. Ignition switch is the current culprit. I have a couple
> spare toggles mounted in the toy, the temptation is to simply light the fire
> with one of them.
>
> --johnny
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>


--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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