Newbie question (first post) Viair or rebuild Dana?

s-m-h

New member
Sep 13, 2019
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Hello all. Thanks you for allowing me to join.

As the title suggests, I'm debating between buying a new Viair 480c or rebuilding my old Dana. I will be upgrading to the 4 bag system as the stock
bags are hooped.

TIA
 
I’m right there too. I think I’ll just rely on my shut-off’s and schrader valves for the near term, but the Wireless Air 72000 from Airlift or the kit on Jim K’s site is in my future. Those both come with compressors, the wireless air has a 33% duty cycle and Jim K’s kit has a 100% duty cycle. If I had a windfall I’d just park the coach with Jim and say go at it!

My bags leak down over a couple of days so there’s a leak somewhere in the system. It might be fun to rebuild the solenoids yet the wireless air just seems so elegant.

Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
Howell EFI + EBL + Electronic Distributor

>
> Hello all. Thanks you for allowing me to join.
>
> As the title suggests, I'm debating between buying a new Viair 480c or rebuilding my old Dana. I will be upgrading to the 4 bag system as the stock
> bags are hooped.
>
> TIA
 
Well, you are in the same position I was in 18 years ago. I attended a seminar at the GMCMI rally and one fellow, I believe it was John Clement, was
having people bring in their Danas and repair / rebuild them in his class. It took about 2 hour. He had all of the parts and tested them at the end.
I listened to all of the "experts" at the time and went and bought a replacement Vlair.

Now 18 years later that Vlair is in a box uninstalled somewhere in my coach. The rebuilt Dana has worked just fine for 18 years. Just fix all of
your air leaks and if you leveling switches work that Dana will kick on once or twice a day while driving. If they do not work then the Dana will
kick on once in 6 or 8 months.

It is all up to you, how much work you want to do, and how much you want to spend.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Im on the fence with you guys as well....i have my original DANA that i took out as it wouldnt pump air worth beans and i replaced it with a known
good DANA....sadly it really doesnt do the job either.

I read all these stories about how that DANA does the job but either i have a monstros air leak (which i dont) or im not letting it run long enough to
build pressure (i think over 25 minutes without air pressure on the gauge is not right).

I just dont see how a 1/8 inch line coming out of compressor can put enough volume into the system to build air effectively or reasonably quick
enough.

Now to be fair maybe the line coming out of the compressor is supposed to be bigger but i cant find a size? Im using a 5psi crack pressure one way
check valve so maybe its to strong,? (That is the recommended crack pressure btw)

So for me its a toss up....do i pull the DANA again and replace it with a Viair or try to make the DANA set up work......
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
What year is your coach? Is it a Power Level, Electro-Level, or
Electro-Level II system?

The Power Level system is entirely pneumatic except for the pump, and uses
a large (~a gallon) storage take mounted up front. The pump’s job is to
keep that tank at a pressure always higher that the bags. When the coach is
low, the leveling valve opens, feeding air from that tank to the bag. When
it is high, it dumps bag air to the outside. The pump has to run from time
to time even when you have no leaks, because it is not a closed system.

I rebuilt my Dana using a kit from Mr. Clement, and not too long after that
replaced it with a Viair. The Dana required much more time to pump that
tank up to the 125 psi required by the pressure switch.

25 minutes without a reading from a known-good pump, though, tells me
something is much more wrong than a tired pump or a slight leak somewhere.
It tells me the check valves aren’t letting air in, the pump/system is
plumbed incorrectly, the gauge is dead, or something significant like that.

Rick “who gets a read in a few seconds with any pump” Denney

On Sat, Sep 14, 2019 at 8:00 AM tonka6cuda6--- via Gmclist <

> Im on the fence with you guys as well....i have my original DANA that i
> took out as it wouldnt pump air worth beans and i replaced it with a known
> good DANA....sadly it really doesnt do the job either.
>
> I read all these stories about how that DANA does the job but either i
> have a monstros air leak (which i dont) or im not letting it run long
> enough to
> build pressure (i think over 25 minutes without air pressure on the gauge
> is not right).
>
> I just dont see how a 1/8 inch line coming out of compressor can put
> enough volume into the system to build air effectively or reasonably quick
> enough.
>
> Now to be fair maybe the line coming out of the compressor is supposed to
> be bigger but i cant find a size? Im using a 5psi crack pressure one way
> check valve so maybe its to strong,? (That is the recommended crack
> pressure btw)
>
> So for me its a toss up....do i pull the DANA again and replace it with a
> Viair or try to make the DANA set up work......
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
 
> What year is your coach? Is it a Power Level, Electro-Level, or
> Electro-Level II system?
>
> The Power Level system is entirely pneumatic except for the pump, and uses
> a large (~a gallon) storage take mounted up front. The pump's job is to
> keep that tank at a pressure always higher that the bags. When the coach is
> low, the leveling valve opens, feeding air from that tank to the bag. When
> it is high, it dumps bag air to the outside. The pump has to run from time
> to time even when you have no leaks, because it is not a closed system.
>
> I rebuilt my Dana using a kit from Mr. Clement, and not too long after that
> replaced it with a Viair. The Dana required much more time to pump that
> tank up to the 125 psi required by the pressure switch.
>
> 25 minutes without a reading from a known-good pump, though, tells me
> something is much more wrong than a tired pump or a slight leak somewhere.
> It tells me the check valves aren't letting air in, the pump/system is
> plumbed incorrectly, the gauge is dead, or something significant like that.
>
> Rick "who gets a read in a few seconds with any pump" Denney
>
> On Sat, Sep 14, 2019 at 8:00 AM tonka6cuda6--- via Gmclist <

>
> > Im on the fence with you guys as well....i have my original DANA that i
> > took out as it wouldnt pump air worth beans and i replaced it with a known
> > good DANA....sadly it really doesnt do the job either.
> >
> > I read all these stories about how that DANA does the job but either i
> > have a monstros air leak (which i dont) or im not letting it run long
> > enough to
> > build pressure (i think over 25 minutes without air pressure on the gauge
> > is not right).
> >
> > I just dont see how a 1/8 inch line coming out of compressor can put
> > enough volume into the system to build air effectively or reasonably quick
> > enough.
> >
> > Now to be fair maybe the line coming out of the compressor is supposed to
> > be bigger but i cant find a size? Im using a 5psi crack pressure one way
> > check valve so maybe its to strong,? (That is the recommended crack
> > pressure btw)
> >
> > So for me its a toss up....do i pull the DANA again and replace it with a
> > Viair or try to make the DANA set up work......
> > --
> > Rich Mondor,
> >
> > Brockville, ON
> >
> > 77 Hughes 2600
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Electro level 1 on mine....if i use my commercial air compressor everything works perfectly....the DANA just doesnt have the volume and/or the
pressure. Im not and engineer, i am a mechanic that works with air systems every day.

As i said, something is amiss on mine....its either the compressor or/and the line size from the compressor to the tank because if i had to guess its
not making over 5psi to crack the valve open....if thats the case it will never add air. (Plus even if it was there is 100psi on the other side of the
check valve that it must overcome and its not doing that for sure)

--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Sorry—it’s hard for me to keep up with everyone’s background as sporadic as
I am.

I sense a Viair pump in your future. Mine fills my large Power Level tank
in less than a couple of minutes.

More here:

http://www.gmcmhphotos.com/photos/g4013-viair-compressor-installation.html

Rick “reliable for the years since” Denney

On Sat, Sep 14, 2019 at 9:24 AM tonka6cuda6--- via Gmclist <

>
> Electro level 1 on mine....if i use my commercial air compressor
> everything works perfectly....the DANA just doesnt have the volume and/or
> the
> pressure. Im not and engineer, i am a mechanic that works with air
> systems every day.
>
> As i said, something is amiss on mine....its either the compressor or/and
> the line size from the compressor to the tank because if i had to guess its
> not making over 5psi to crack the valve open....if thats the case it will
> never add air. (Plus even if it was there is 100psi on the other side of the
> check valve that it must overcome and its not doing that for sure)
>
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
 
I have repaired many air systems with good success. Thing is I have not found a silver bullet. They all had different issues. Air leaks were most
common around the factory connectors, around the brake booster, on the back of the manual valves and the check valves being bad. The outside air
tanks get pin holes. The solenoids get corroded and dirty. First thing I do is put a schrader valve in the tank and start looking for leaks. With
a good check valve and electric switch and plugs and connectors, tank should hold air overnight. From there check air line connectors and solenoids
then control valves. If the system is tight any good compressor will do the job. There are no short cuts. I do prefer the marked DOT push on
connectors. They are easy and do not damage line or fitting when reused. I cut the plastic line with a sharp razor blade then fine sand paper to
un-sharpen the cut edge and use a small amount of rubber lube or tire soap. Push hard to seat.
--
C. Boyd
76 Crestmont
East Tennessee
 
Best prevention to keep a good system good is a water separator on tank and a drain valve on tank to keep water that naturally occurs when air is
compressed. Big trucks that rely on air for suspension and brakes have a huge filter and spitter valve that spits the moisture out every time the
compressor cycles.

> I have repaired many air systems with good success. Thing is I have not found a silver bullet. They all had different issues. Air leaks were
> most common around the factory connectors, around the brake booster, on the back of the manual valves and the check valves being bad. The outside
> air tanks get pin holes. The solenoids get corroded and dirty. First thing I do is put a schrader valve in the tank and start looking for leaks.
> With a good check valve and electric switch and plugs and connectors, tank should hold air overnight. From there check air line connectors and
> solenoids then control valves. If the system is tight any good compressor will do the job. There are no short cuts. I do prefer the marked DOT
> push on connectors. They are easy and do not damage line or fitting when reused. I cut the plastic line with a sharp razor blade then fine sand
> paper to un-sharpen the cut edge and use a small amount of rubber lube or tire soap. Push hard to seat.

--
C. Boyd
76 Crestmont
East Tennessee
 
Thanks for the replies fellas. My coach is a 77 Palm Beach with the closet installed compressor system. Electro level.
 
> Best prevention to keep a good system good is a water separator on tank and a drain valve on tank to keep water that naturally occurs when air is
> compressed. Big trucks that rely on air for suspension and brakes have a huge filter and spitter valve that spits the moisture out every time the
> compressor cycles.
>
>
>

> > I have repaired many air systems with good success. Thing is I have not found a silver bullet. They all had different issues. Air leaks were
> > most common around the factory connectors, around the brake booster, on the back of the manual valves and the check valves being bad. The
> > outside air tanks get pin holes. The solenoids get corroded and dirty. First thing I do is put a schrader valve in the tank and start looking
> > for leaks. With a good check valve and electric switch and plugs and connectors, tank should hold air overnight. From there check air line
> > connectors and solenoids then control valves. If the system is tight any good compressor will do the job. There are no short cuts. I do prefer
> > the marked DOT push on connectors. They are easy and do not damage line or fitting when reused. I cut the plastic line with a sharp razor blade
> > then fine sand paper to un-sharpen the cut edge and use a small amount of rubber lube or tire soap. Push hard to seat.

Yup...mine holds air for a few weeks (actually the left side has a tiny leak that i need to find but it still take 2 weeks to drop half way).

Problem foe me is compressor.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Sir, since your question was generalized it don't mean much in this case but normally it is an enormous help to those that are trying to diagnose
your problems from our recliners if we know the year and model of your coach and is much more friendly if we know your name. Matt must be sleeping in
today, probably from working on his coach to get ready for Mansfield. He is kinda our unofficial greeter and all round nice guy.

The GMC had 4 different air systems, one did not have dash controls for campsite leveling, one had manual dash valves for leveling with an external
compressor and large air tank, next series had electric switches with solenoids and relays with a compressor and small storage tank inside a cabinet
or under a bed or hid almost anywhere depending on model. The third and last series was electro level II and my favorite. It used same switches,
relays, and a couple of the same 2 way solenoids as electro level I, but had a photocell electronic control in the fenderwell instead of the early
type manual air in/dump valve. The electronic photo eye system controlled the ground to each of 2 independent compressors ( one for each side and no
storage tank) that had the dump air solenoid valve in the head of the special compressor. The system was "hot 12 volt" anytime the key was on and
the photocell controlled the ground to the relays that would control the solenoids and compressors to air up or dump air to lower.

> Hello all. Thanks you for allowing me to join.
>
> As the title suggests, I'm debating between buying a new Viair 480c or rebuilding my old Dana. I will be upgrading to the 4 bag system as the
> stock bags are hooped.
>
> TIA

--
C. Boyd
76 Crestmont
East Tennessee
 
Green,

Welcome to the group, family, cult, asylum.....

While a New Viair is more expensive, my Dana pump has done very well until it was damaged in a recent incident. I am not at all sure I would rebuild
it again.

You found your way here and that is real good. You will also quickly learn that the coach connects you to an amazing community. We all want to see
that you can enjoy both your coach itself and what it can do for you. To this end and as you seem to be working with us as the forum, please fill in
a sigfile. You can do this easily by going up to then choose and you will see the Signature Box. You
can put in a name you like to be know by in person because you will meet other owners (that is a given and real names are good here), a short about
the coach including an major mods - this is essential because there are many differences and some matter a lot - and finally a geographic reference,
so far all we see is a Canadian flag, and you might have a brand new old friend near by that can be of some assistance.

This is an amazing community. These people are helping and supportive to a level you might not believe, but we all have stories (both ways). That
level of support is not easy to find anywhere. As the only other community that provides that level of support and assistance that I know of is that
of the watermen that are my world. For that very reason, I welcome new owners here with a paraphrase of how one would be greeted there. So,

May the Good Lord bless this coach and all those that set forth within her.

Welcome Green

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Done and done! Thank you for the warm welcome!

I am leaning towards a rebuild based on what I'm hearing thus far. I like to keep things original as possible.

The coach is completely stock mechanically. The interior is completely gutted, a blank canvas. The idea is to begin with ensuring it is mechanically
sound (including air ride)before I even think about the interior, generator etc.

--
1977 Palm Beach 403

Shawn

North Vancouver,
Canada
 
Did you check and set the timing between the two cylinders of the Dana pump? One must be all the way up while the other is all the way down.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
How in the world would you fix that??

>
> Did you check and set the timing between the two cylinders of the Dana pump? One must be all the way up while the other is all the way down.
> --
> Ken Burton - N9KB
 
The timing belt

On Sat, Sep 14, 2019 at 11:20 AM Larry Davick via Gmclist <

> How in the world would you fix that??
>
> > On Sep 14, 2019, at 10:38 AM, Ken Burton via Gmclist <

> >
> > Did you check and set the timing between the two cylinders of the Dana
> pump? One must be all the way up while the other is all the way down.
> > --
> > Ken Burton - N9KB
>
>
> _______________________________________________
> 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
 
X 7525 75-76 maintenance manual rear suspension section 4 page 17 starts Dana dual cylinder compressor overhaul.

> How in the world would you fix that??
>

> >
> > Did you check and set the timing between the two cylinders of the Dana pump? One must be all the way up while the other is all the way
> > down.
> > --
> > Ken Burton - N9KB
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
C. Boyd
76 Crestmont
East Tennessee
 
https://www.gmcmi.com/wp-content/uploads/2014/05/X7525_75-76-maint-manual.pdf

> X 7525 75-76 maintenance manual rear suspension section 4 page 17 starts Dana dual cylinder compressor overhaul.
>
>
>
>
>
>

> > How in the world would you fix that??
> >

> > >
> > > Did you check and set the timing between the two cylinders of the Dana pump? One must be all the way up while the other is all the way
> > > down.
> > > --
> > > Ken Burton - N9KB
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
C. Boyd
76 Crestmont
East Tennessee
 
Thank you for pointing me to that manual. I'd never known that the Dana was really just two separate compressors running from one motor. I thought
they shared a crankshaft like a V-Twin.
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy