Powerlevel in early '76

[ejames]

I just recently purchased a '76 Glenbrook, #40 built for that model year so
it still has the knob type controls. If I leave the controls in Travel or
Hold after a few hours the bags and tank empty and low air light comes on
if I put the key in. The PO's son changed the bags with OEM bags before
we bought it. I did a soap test on all the fittings I could see and I
found a small leak on the drive side fitting at the air bag. After
tightening that up it's still losing air somewhere.

Is the hold control suppose to lock in place? When I switch from travel to
raise it has some resistance and "clicks", but when you go down to hold
it's free, there is no resistance or a designated stop place.

Is it likely the leak is in the controls? I haven't removed them from the
dash to look yet.

--
Ethan James
76 Glenbrook
Roanoke, VA

 

[Jim Hupy]

Knobs leak frequently. Cure? J.R. Slaten valves. That takes care of the
valve leaks, but you still have loss from the miles of various colored
plastic tubes, height valves, reservoir tank and fittings, compressor back
flow, etc. Simple fix? Schrader valves at the air bags, with shut offs.
More complex and expensive, wireless air.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> I just recently purchased a '76 Glenbrook, #40 built for that model year so
> it still has the knob type controls. If I leave the controls in Travel or
> Hold after a few hours the bags and tank empty and low air light comes on
> if I put the key in. The PO's son changed the bags with OEM bags before
> we bought it. I did a soap test on all the fittings I could see and I
> found a small leak on the drive side fitting at the air bag. After
> tightening that up it's still losing air somewhere.
>
> Is the hold control suppose to lock in place? When I switch from travel to
> raise it has some resistance and "clicks", but when you go down to hold
> it's free, there is no resistance or a designated stop place.
>
> Is it likely the leak is in the controls? I haven't removed them from the
> dash to look yet.
>
> --
> Ethan James
> 76 Glenbrook
> Roanoke, VA
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[johnny]

J.R. Slaten is Your Friend. I have his valves and a ViAir compressor along with original bags in my 23' coach. Stays level. It also has shutoffs
which I use when it's parked.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon

 

[Keith V]

The dash knob valves are the biggest problem with tthe power level. They are cheap pot metal and leak terribly.
I ended up gluing mine all up which helped, but they are old and leaky.
JR Slatten valves are way better.

The up/down/travel positions have a detent, the hold position does not. Hold is actually between any of the three detent positions.
If you see any soap bubbles you have a leak. A tight system will not blow bubbles.

The tubing doesn't leak but the valves and connections do. When I was using the stock system I used shutoff valves on the bags to keep them up, otherwise theyed deflate overnight

----------------------------------------

>
> Knobs leak frequently. Cure? J.R. Slaten valves. That takes care of the
> valve leaks, but you still have loss from the miles of various colored
> plastic tubes, height valves, reservoir tank and fittings, compressor back
> flow, etc. Simple fix? Schrader valves at the air bags, with shut offs.
> More complex and expensive, wireless air.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403

>
>> I just recently purchased a '76 Glenbrook, #40 built for that model year so
>> it still has the knob type controls. If I leave the controls in Travel or
>> Hold after a few hours the bags and tank empty and low air light comes on
>> if I put the key in. The PO's son changed the bags with OEM bags before
>> we bought it. I did a soap test on all the fittings I could see and I
>> found a small leak on the drive side fitting at the air bag. After
>> tightening that up it's still losing air somewhere.
>>
>> Is the hold control suppose to lock in place? When I switch from travel to
>> raise it has some resistance and "clicks", but when you go down to hold
>> it's free, there is no resistance or a designated stop place.
>>
>> Is it likely the leak is in the controls? I haven't removed them from the
>> dash to look yet.
>>
>> --
>> Ethan James
>> 76 Glenbrook
>> Roanoke, VA
>> _______________________________________________
>> 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

 

[sgltrac]

if you have shut off and Schrader valves at each bag you can rule out or
identify the leak at the bag or any fitting between the shut off and the
bag very easily. Shut off and Schrader valves are super handy for quick
leveling via standalone air source or to fill / deflate the bags when you
are lifting or performing maintenance on the rear of the coach. If you do
not have a set I recommend you purchase one. They are available from myself
as well as Applied and probably others. Once installed, set your ride
height with the oem air system and close the shut off valves. Saturate all
fittings between the shut off and the bag with soapy water and check for
bubbles or foaming. If you see either correct the plumbing connection and
re test with soapy water until no bubbles or foam. If your coach still
drops over time with no leak in your fittings behind the shut off and your
valves are closed at least one of your leaks is the airbag. Replace the
airbag(s) if it(they) leak and then see how your system holds up with no
other changes. If you encounter loss of pressure (ride height) afterward
you will at least have the option of differing repairs on the air system
until you find someone willing and capable of diagnosing leaks in the
system (gmc rally).
Another benefit of shut off and Schrader valves is the ability to continue
with your coach even with a complete compressor system malfunction as the
coach can be easily lifted to ride height with an outside air source and
then isolated from the rest of the air plumbing with the shut off valve.

my 2c

sully
77 eleganza 2
seattle

> I just recently purchased a '76 Glenbrook, #40 built for that model year so
> it still has the knob type controls. If I leave the controls in Travel or
> Hold after a few hours the bags and tank empty and low air light comes on
> if I put the key in. The PO's son changed the bags with OEM bags before
> we bought it. I did a soap test on all the fittings I could see and I
> found a small leak on the drive side fitting at the air bag. After
> tightening that up it's still losing air somewhere.
>
> Is the hold control suppose to lock in place? When I switch from travel to
> raise it has some resistance and "clicks", but when you go down to hold
> it's free, there is no resistance or a designated stop place.
>
> Is it likely the leak is in the controls? I haven't removed them from the
> dash to look yet.
>
> --
> Ethan James
> 76 Glenbrook
> Roanoke, VA
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[bdub]

http://www.bdub.net/slaton/

>
> I just recently purchased a '76 Glenbrook, #40 built for that model year
so
> it still has the knob type controls. If I leave the controls in Travel or
> Hold after a few hours the bags and tank empty and low air light comes on
> if I put the key in. The PO's son changed the bags with OEM bags before
> we bought it. I did a soap test on all the fittings I could see and I
> found a small leak on the drive side fitting at the air bag. After
> tightening that up it's still losing air somewhere.
>
> Is the hold control suppose to lock in place? When I switch from travel to
> raise it has some resistance and "clicks", but when you go down to hold
> it's free, there is no resistance or a designated stop place.
>
> Is it likely the leak is in the controls? I haven't removed them from the
> dash to look yet.

 

[ejames]

Thanks for the info guys.

I ordered some shutoff values since I needed some other stuff from
applied. I'll plan on upgrading the controls in the spring.

 

[burt and faye curtis]

Remember that if the new bag is leaking at the fitting area it could be the
o ring.

Fay
Curtis
'76 Glenbrook
Kneeland, Ca

> Thanks for the info guys.
>
> I ordered some shutoff values since I needed some other stuff from
> applied. I'll plan on upgrading the controls in the spring.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Gene Fisher]

Remember

Schrader valves are good
But not for continuous use
One day the air bag will explode, and your head or hand had
Better not be in there
http://bdub.net/gmcmotorhome.info/wireless.html

On Wednesday, October 5, 2016, Burt and Faye curtis <
curtisunlimitedbandf

> Remember that if the new bag is leaking at the fitting area it could be the
> o ring.
>
> Fay
> Curtis
> '76 Glenbrook
> Kneeland, Ca

>
> > Thanks for the info guys.
> >
> > I ordered some shutoff values since I needed some other stuff from
> > applied. I'll plan on upgrading the controls in the spring.
> > _______________________________________________
> > 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
>

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

 

[wally anderson]

> I just recently purchased a '76 Glenbrook, #40 built for that model year so
> it still has the knob type controls. If I leave the controls in Travel or
> Hold after a few hours the bags and tank empty and low air light comes on
> if I put the key in. The PO's son changed the bags with OEM bags before
> we bought it. I did a soap test on all the fittings I could see and I
> found a small leak on the drive side fitting at the air bag. After
> tightening that up it's still losing air somewhere.
>
> Is the hold control suppose to lock in place? When I switch from travel to
> raise it has some resistance and "clicks", but when you go down to hold
> it's free, there is no resistance or a designated stop place.
>
> Is it likely the leak is in the controls? I haven't removed them from the
> dash to look yet.
>
> --
> Ethan James
> 76 Glenbrook
> Roanoke, VA
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

We were able to reseal the original rotary valves with a kit from Jim k. It had the o rings and new body gaskets. Some have had issues with valve body
porosity but ours are ok. They have no real detent in the hold position. Been about 10 years since kit installation and they still hold good.
--
Wally Anderson
1975 Glenbrook
Megasquirt 455 port injection science project
Omaha Nebraska
Bob Stone hydroBOOOOST
Greater Midwest Classics
GMCES
http://wallyandsue.blogspot.com/

 

[ejames]

I installed the shutoff valves at the airbags. Does this look correct? Not
sure about the clearance.

Driver side: http://i.imgur.com/XTNASj0h.jpg
Passenger side: http://i.imgur.com/wI3Ijt6h.jpg

Also do I have enough slack in the driver side air supply tube?

I assume when driving I should open these valves and set the system to
travel mode and just let it manage everything?

> > I just recently purchased a '76 Glenbrook, #40 built for that model year
> so
> > it still has the knob type controls. If I leave the controls in Travel
> or
> > Hold after a few hours the bags and tank empty and low air light comes on
> > if I put the key in. The PO's son changed the bags with OEM bags before
> > we bought it. I did a soap test on all the fittings I could see and I
> > found a small leak on the drive side fitting at the air bag. After
> > tightening that up it's still losing air somewhere.
> >
> > Is the hold control suppose to lock in place? When I switch from travel
> to
> > raise it has some resistance and "clicks", but when you go down to hold
> > it's free, there is no resistance or a designated stop place.
> >
> > Is it likely the leak is in the controls? I haven't removed them from
> the
> > dash to look yet.
> >
> > --
> > Ethan James
> > 76 Glenbrook
> > Roanoke, VA
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> We were able to reseal the original rotary valves with a kit from Jim k.
> It had the o rings and new body gaskets. Some have had issues with valve
> body
> porosity but ours are ok. They have no real detent in the hold position.
> Been about 10 years since kit installation and they still hold good.
> --
> Wally Anderson
> 1975 Glenbrook
> Megasquirt 455 port injection science project
> Omaha Nebraska
> Bob Stone hydroBOOOOST
> Greater Midwest Classics
> GMCES
> http://wallyandsue.blogspot.com/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[robert mueller]

Ethan,

COMMENTS BELOW IN CAPS FOR CLARITY I'M NOT SHOUTING.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Ethan James

I installed the shutoff valves at the airbags. Does this look correct?

LOOKS OK TO ME.

Not sure about the clearance.

RAISE THE REAR TO THE MAX AND THEN DROP IT TO THE MIN AND CHECK THE CLEARANCE.

Driver side: http://i.imgur.com/XTNASj0h.jpg

Passenger side: http://i.imgur.com/wI3Ijt6h.jpg

Also do I have enough slack in the driver side air supply tube?

RAISE THE REAR TO THE MAX AND THEN DROP IT TO THE MIN AND CHECK THE CLEARANCE.

I assume when driving I should open these valves and set the system to travel mode and just let it manage everything?

YES

I WOULD FOLLOW WALLY'S SUGGESTION AND REBUILD THE VALVES FOR $26.95!

http://www.appliedgmc.com/prod.itml/icOid/953

Ethan

 

[thomas phipps]

After determining the air pressure to maintain the proper ride height, you can always shut the bag out of the system with the cutoff valve.
Tom, MS II
--
1975 GMC Avion
KA4CSG

 

[Ken B]

You are going to love those valves until one of them breaks off flush with the bag.

I had blacklist call from a young lady one day that said her air bag blew. When I got there the bag was fine but the pipe between the bag and the
valve broke from bouncing up and down with the extra weight of the valve hanging on it. It was not a fun day as I could not get the broken pipe out
of it on the road. Also bag mounting nuts were rusted badly. I ended up calling a buddy to bring out a flame wrench to use on both of the nuts. We
took the bag to the shop to remove the broken pipe.

We reinstalled the bag with new stainless nuts, stainless tooth washers, and anti-seize but WITHOUT the shutoff valve. We also removed the other one
from the other side.

It was not a fun day working on that thing along the Interstate.

I would not have those valves anywhere near my coach. Fix whatever is wrong with the air system and get rid of those shutoff valves. I do carry a
pair of schrader valves to use in an emergency, but I have never needed them.

If you use them you are crippling your automatic air adjustment system and introducing another possible failure point.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Jim Hupy]

The combined weight of the shut off valves hung out a good ways from the
bag, almost insures some bouncing. Bend anything back and forth enough
cycles and failure is immenent. Best way is to mount the shut off valve and
Schrader valve on a manifold and attach it to the wheel well high and out
of the way of a blowout. Then just plumb the air line to the bag. Ez-Pz.
Jim Hupy
Salem, Or. (Presently at Coos Bay, Or. In bright sunshine. No breeze at
present. GMCWS multi club rally)

> You are going to love those valves until one of them breaks off flush with
> the bag.
>
> I had blacklist call from a young lady one day that said her air bag
> blew. When I got there the bag was fine but the pipe between the bag and
> the
> valve broke from bouncing up and down with the extra weight of the valve
> hanging on it. It was not a fun day as I could not get the broken pipe out
> of it on the road. Also bag mounting nuts were rusted badly. I ended up
> calling a buddy to bring out a flame wrench to use on both of the nuts. We
> took the bag to the shop to remove the broken pipe.
>
> We reinstalled the bag with new stainless nuts, stainless tooth washers,
> and anti-seize but WITHOUT the shutoff valve. We also removed the other one
> from the other side.
>
> It was not a fun day working on that thing along the Interstate.
>
> I would not have those valves anywhere near my coach. Fix whatever is
> wrong with the air system and get rid of those shutoff valves. I do carry a
> pair of schrader valves to use in an emergency, but I have never needed
> them.
>
> If you use them you are crippling your automatic air adjustment system and
> introducing another possible failure point.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[sgltrac]

I suppose a fatigue failure of a shut off / schrader valve set up is
possible but I suspect a failure like Ken reported is more likely the
result of a fitting which had been weakened by some other prior event
, improper installation or debris kicked up from the roadway. I also
believe that the cause when being marooned by the rear suspension system is
far more likely to be a failure of the 40 year old compressed air system,
plumbing and assorted electrical controls than a newly installed schrader
and ball valve set up.

My 2c

Sully
77 eleganza2
Seattle

> The combined weight of the shut off valves hung out a good ways from the
> bag, almost insures some bouncing. Bend anything back and forth enough
> cycles and failure is immenent. Best way is to mount the shut off valve and
> Schrader valve on a manifold and attach it to the wheel well high and out
> of the way of a blowout. Then just plumb the air line to the bag. Ez-Pz.
> Jim Hupy
> Salem, Or. (Presently at Coos Bay, Or. In bright sunshine. No breeze at
> present. GMCWS multi club rally)
> On Oct 9, 2016 2:55 PM, "Ken Burton"

>
> > You are going to love those valves until one of them breaks off flush
> with
> > the bag.
> >
> > I had blacklist call from a young lady one day that said her air bag
> > blew. When I got there the bag was fine but the pipe between the bag and
> > the
> > valve broke from bouncing up and down with the extra weight of the valve
> > hanging on it. It was not a fun day as I could not get the broken pipe
> out
> > of it on the road. Also bag mounting nuts were rusted badly. I ended
> up
> > calling a buddy to bring out a flame wrench to use on both of the nuts.
> We
> > took the bag to the shop to remove the broken pipe.
> >
> > We reinstalled the bag with new stainless nuts, stainless tooth washers,
> > and anti-seize but WITHOUT the shutoff valve. We also removed the other
> one
> > from the other side.
> >
> > It was not a fun day working on that thing along the Interstate.
> >
> > I would not have those valves anywhere near my coach. Fix whatever is
> > wrong with the air system and get rid of those shutoff valves. I do
> carry a
> > pair of schrader valves to use in an emergency, but I have never needed
> > them.
> >
> > If you use them you are crippling your automatic air adjustment system
> and
> > introducing another possible failure point.
> > --
> > Ken Burton - N9KB
> > 76 Palm Beach
> > Hebron, Indiana
> >
> > _______________________________________________
> > 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
>

 

[robert mueller]

G'day,

MM X-7525 / Section 4 - Rear Suspension / Page 4-6 / Trouble Shooting Chart / Correction 5. Adjust pressure switch settings to
operate at 100 - 120 psi range.

IIRC the relief valve in Double Trouble's PowerLevel air tank is set at 140 psi (as measured on the 2" gage).

I'll bet dollars to donuts that the OEM bags will take 150% of that (210psi) without any problem and possibly more as that would be
a prudent design point.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

 

[Keith V]

I'd vote for a low quality fitting.
It should be near impossible to ruin a fitting during installation, youd have to really work at it.
Then again, I have see what the PO thinks is correct....

----------------------------------------
> From: sgltrac
> Date: Sun, 9 Oct 2016 15:59:38 -0700
> To: gmclist
> Subject: Re: [GMCnet] Powerlevel in early '76
>
> I suppose a fatigue failure of a shut off / schrader valve set up is
> possible but I suspect a failure like Ken reported is more likely the
> result of a fitting which had been weakened by some other prior event
> , improper installation or debris kicked up from the roadway. I also
> believe that the cause when being marooned by the rear suspension system is
> far more likely to be a failure of the 40 year old compressed air system,
> plumbing and assorted electrical controls than a newly installed schrader
> and ball valve set up.
>
> My 2c
>
> Sully
> 77 eleganza2
> Seattle
>

>
>> The combined weight of the shut off valves hung out a good ways from the
>> bag, almost insures some bouncing. Bend anything back and forth enough
>> cycles and failure is immenent. Best way is to mount the shut off valve and
>> Schrader valve on a manifold and attach it to the wheel well high and out
>> of the way of a blowout. Then just plumb the air line to the bag. Ez-Pz.
>> Jim Hupy
>> Salem, Or. (Presently at Coos Bay, Or. In bright sunshine. No breeze at
>> present. GMCWS multi club rally)
>> On Oct 9, 2016 2:55 PM, "Ken Burton"

>>
>>> You are going to love those valves until one of them breaks off flush
>> with
>>> the bag.
>>>
>>> I had blacklist call from a young lady one day that said her air bag
>>> blew. When I got there the bag was fine but the pipe between the bag and
>>> the
>>> valve broke from bouncing up and down with the extra weight of the valve
>>> hanging on it. It was not a fun day as I could not get the broken pipe
>> out
>>> of it on the road. Also bag mounting nuts were rusted badly. I ended
>> up
>>> calling a buddy to bring out a flame wrench to use on both of the nuts.
>> We
>>> took the bag to the shop to remove the broken pipe.
>>>
>>> We reinstalled the bag with new stainless nuts, stainless tooth washers,
>>> and anti-seize but WITHOUT the shutoff valve. We also removed the other
>> one
>>> from the other side.
>>>
>>> It was not a fun day working on that thing along the Interstate.
>>>
>>> I would not have those valves anywhere near my coach. Fix whatever is
>>> wrong with the air system and get rid of those shutoff valves. I do
>> carry a
>>> pair of schrader valves to use in an emergency, but I have never needed
>>> them.
>>>
>>> If you use them you are crippling your automatic air adjustment system
>> and
>>> introducing another possible failure point.
>>> --
>>> Ken Burton - N9KB
>>> 76 Palm Beach
>>> Hebron, Indiana
>>>
>>> _______________________________________________
>>> 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