Rear suspension raising issue

[dave pottebaum]

Hello, I've got a 1978 Royale with the electro level 1 system. When I'm trying to level at a campsite neither side will raise. They will both lower.
The compressor fires up to get the tank pressure to 120 pounds at vehicle start up, but nothing actually happens when I try to inflate the bags. I
am unsure if the system is working in Travel mode while going down the road. I have tried both Travel and Hold while at the campsite with no success.
Is it possible that both raise solenoids failed at the same time? Seems unusual for that to happen as well as having both switches fail or both
circuits lose continuity (although I have not checked for that). The 30 AMP fuse at the glove box is also fine. I have not bench tested the
solenoids. I'm sure I'm missing something obvious. Thanks for any insights.
--
Dave Pottebaum
Bondurant, Iowa
1978 Royale

 

[douglas smith]

Dave,
I’ve got the same “problem.” The issue is that if the whole system has more pressure than your pump relay wants to start the pump, it’s not gonna go. I just drop the pressure in a bag and then raise it enough to activate the pump, then it raises everything till it shuts off at the high pressure cutoff. Wiser people will correct me here, but I don’t think either of us has a problem.
Doug

Douglas & Virginia Smith
dsmithy18 at gmail
Lincoln Nebraska
’73 “Canyonlands” since ‘95: “Wanabizo”, Anishinabe Indian for “He gets lost driving” Yes, really.
Quadrabag/6 wheel disks/3;70 final/Paterson QuadraJet/Thorley’s/Sundry other
P&W PT6, no wait, that's the wish list...

>
> Hello, I've got a 1978 Royale with the electro level 1 system. When I'm trying to level at a campsite neither side will raise. They will both lower.
> The compressor fires up to get the tank pressure to 120 pounds at vehicle start up, but nothing actually happens when I try to inflate the bags. I
> am unsure if the system is working in Travel mode while going down the road. I have tried both Travel and Hold while at the campsite with no success.
> Is it possible that both raise solenoids failed at the same time? Seems unusual for that to happen as well as having both switches fail or both
> circuits lose continuity (although I have not checked for that). The 30 AMP fuse at the glove box is also fine. I have not bench tested the
> solenoids. I'm sure I'm missing something obvious. Thanks for any insights.
> --
> Dave Pottebaum
> Bondurant, Iowa
> 1978 Royale
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[douglas smith]

Sorry Dave, I just gave you a non-solution. The electro-level guys should weigh in here.
Doug

Douglas & Virginia Smith
dsmithy18 at gmail
Lincoln Nebraska
’73 “Canyonlands” since ‘95: “Wanabizo”, Anishinabe Indian for “He gets lost driving” Yes, really.
Quadrabag/6 wheel disks/3;70 final/Paterson QuadraJet/Thorley’s/Sundry other
P&W PT6, no wait, that's the wish list...

>
> Hello, I've got a 1978 Royale with the electro level 1 system. When I'm trying to level at a campsite neither side will raise. They will both lower.
> The compressor fires up to get the tank pressure to 120 pounds at vehicle start up, but nothing actually happens when I try to inflate the bags. I
> am unsure if the system is working in Travel mode while going down the road. I have tried both Travel and Hold while at the campsite with no success.
> Is it possible that both raise solenoids failed at the same time? Seems unusual for that to happen as well as having both switches fail or both
> circuits lose continuity (although I have not checked for that). The 30 AMP fuse at the glove box is also fine. I have not bench tested the
> solenoids. I'm sure I'm missing something obvious. Thanks for any insights.
> --
> Dave Pottebaum
> Bondurant, Iowa
> 1978 Royale
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[dave pottebaum]

Thanks Doug. I'll keep trying things today. I see the William Schurman started a new thread with a similar problem except his is isolated to one
side. My son is home today so we'll tag team on this and keep tracing the problem back.
--
Dave Pottebaum
Bondurant, Iowa
1978 Royale

 

[dave pottebaum]

While I'm replacing a couple 2 way solenoids, I am also going to replace the pressure switch. It had a P61NA-10 Johnson Controls switch in it. I
have not had much luck finding an equivalent. Anyone have some suggestions for a good replacement? Thanks.
--
Dave Pottebaum
Bondurant, Iowa
1978 Royale

 

[emerystora]

The GMC originally came with a shallow well pressure switch. Check Amazon under that description. There are many.
Here is one that should probably work but check the pressure on and pressure setting ability.

https://www.amazon.com/Square-Schneider-Electric-FSG2J24CP-Pumptrol/dp/B000BQSERE/ref=sr_1_9?crid=1QMWLTQTECNNU&keywords=shallow+well+pressure+switch&qid=1569811976&s=gateway&sprefix=shallow+well+pressure%2Caps%2C173&sr=8-9 https://www.amazon.com/Square-Schneider-Electric-FSG2J24CP-Pumptrol/dp/B000BQSERE/ref=sr_1_9?crid=1QMWLTQTECNNU&keywords=shallow+well+pressure+switch&qid=1569811976&s=gateway&sprefix=shallow+well+pressure,aps,173&sr=8-9

Emery Stora
77 Kingsley
Frederick, CO

>
> While I'm replacing a couple 2 way solenoids, I am also going to replace the pressure switch. It had a P61NA-10 Johnson Controls switch in it. I
> have not had much luck finding an equivalent. Anyone have some suggestions for a good replacement? Thanks.
> --
> Dave Pottebaum
> Bondurant, Iowa
> 1978 Royale

 

[jim kanomata1]

We stock two kind, one has a unloader option gmcrvparts.com

On Sun, Sep 29, 2019 at 8:00 PM Emery Stora via Gmclist <

> The GMC originally came with a shallow well pressure switch. Check Amazon
> under that description. There are many.
> Here is one that should probably work but check the pressure on and
> pressure setting ability.
>
>
> https://www.amazon.com/Square-Schneider-Electric-FSG2J24CP-Pumptrol/dp/B000BQSERE/ref=sr_1_9?crid=1QMWLTQTECNNU&keywords=shallow+well+pressure+switch&qid=1569811976&s=gateway&sprefix=shallow+well+pressure%2Caps%2C173&sr=8-9
> <
> https://www.amazon.com/Square-Schneider-Electric-FSG2J24CP-Pumptrol/dp/B000BQSERE/ref=sr_1_9?crid=1QMWLTQTECNNU&keywords=shallow+well+pressure+switch&qid=1569811976&s=gateway&sprefix=shallow+well+pressure,aps,173&sr=8-9
> >
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>
> > On Sep 29, 2019, at 8:45 PM, Dave Pottebaum via Gmclist <

> >
> > While I'm replacing a couple 2 way solenoids, I am also going to replace
> the pressure switch. It had a P61NA-10 Johnson Controls switch in it. I
> > have not had much luck finding an equivalent. Anyone have some
> suggestions for a good replacement? Thanks.
> > --
> > Dave Pottebaum
> > Bondurant, Iowa
> > 1978 Royale
>
> _______________________________________________
> 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

 

[Ken B]

These switches are used on air compressors and fairly common. The problem is there are many different types ans specs. The easiest thing is to order
one form Jim K as he has already figured out which one is the correct one. I would get the one with the unloader, even if you do not implement it
now it is a simple addition to later to add one Tee and a short piece of hose.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[john r. lebetski]

78 with EL1? That's confusing.
My guess is gummed contacts on the switch panel switches. The thin foam dust shield turns to foam goo and gets in the contacts You can unplug the
panel and bench test continuity functions on the bench. Then open and service the switches if need be. Very easy on a clean bench, just watch springs
and small parts. I had to physically clean the contact points as the little foam balls bonded to contacts
I don't know why you are chasing pressure switch if there is120PSI at tank
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[john r. lebetski]

If you think about it, the UP contacts are closer to the bottom of the switch where more debris would collect.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[dave pottebaum]

John, thanks for the suggestions. The pressure switch is unrelated to the problem I was asking about. I broke a connection on the switch when I was
taking things apart. As for the EL 1, that's what it is. Some 78's had them and others had the EL2. Apparently, it was a transition year similar to
the 455 to 403 the year before.
--
Dave Pottebaum
Bondurant, Iowa
1978 Royale

 

[dave pottebaum]

I just ordered the switch with the unloader from Jim. Thanks for the suggestion, Ken.
--
Dave Pottebaum
Bondurant, Iowa
1978 Royale