Home » Public Forums » GMCnet » [GMCnet] v-twin air compressor has low pressure
| [GMCnet] v-twin air compressor has low pressure [message #262320] |
Fri, 19 September 2014 12:58  |
Bob Wright
Messages: 30
Registered: August 2014
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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  |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Bob Wright wrote on Fri, 19 September 2014 10:58Does 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
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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 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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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/
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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 |
emerystora
Messages: 4442
Registered: January 2004
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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 #262350 is a reply to message #262345] |
Fri, 19 September 2014 21:29 |
Bob Wright
Messages: 30
Registered: August 2014
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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 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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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
>>
>> _______________________________________________
>> GMCnet mailing list
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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
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| Re: [GMCnet] v-twin air compressor has low pressure [message #262433 is a reply to message #262412] |
Sat, 20 September 2014 21:53 |
Bob Wright
Messages: 30
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
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>>
>> _______________________________________________
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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 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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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
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| Re: [GMCnet] v-twin air compressor has low pressure [message #262463 is a reply to message #262462] |
Sun, 21 September 2014 09:19 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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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 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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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
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| Re: [GMCnet] v-twin air compressor has low pressure [message #262502 is a reply to message #262499] |
Sun, 21 September 2014 20:11 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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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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