Changing rear tires.

J

john phillips

New member
Jul 30, 2017
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I started to look for a leaky wheel cylinder and pack the bearing on my
rear wheels.
I raised the coach to max height and block it there. I then bled the air
out and the center axle tires come off the ground. The rear axle tires
stayed on the ground. I was able to remove the driver's side rear tire but
the passenger side seems to have > 200 lbs resting on the tire. I put a bar
under it pry it up but it came back down. The center axle did come down
when the rear when up. What could be causing the load on this axle? I did
not think needed a jack to remove tires from the back axle.

John Phillips
26 foot Avion 75
Rancho Cordova, CA
 
With the air pressure released from the air bags the only 'weight' on the tire is the weight of the tire, wheel, brake assembly and bogie arm.

A stiff bogie pivot could seem like extra weight.
An off-normal shock could also add extra 'weight'. A gas-charged shock will help lift the wheel/bogie arm a bit.

When the bogie drops down as airbags are deflated the shock is compressed limiting the travel downward.
Make sure you are raising the coach enough to allow the shocks to be fully compressed.
Don't let filled airbags push the shocks to full compression.
Deflated them before the tires start to come off of the ground when raising the back end.

Rick M.
--
1974 26' Canyonlands
aka "The General"
Clinton, TN
 
I inflated the airbags and then blocked under the bogie frame. I then
deflated the airbag and the center wheels came off the ground but the back
tires stayed on the ground. The left one did not have much weight on it
and I was able to take that tire off, the right side still has weight from
someplace and comes back down when it is pried up. I do not think I have an
air shock on the back axle but this coach is new to me so I will check for
an airline tomorrow.
Not to hijack this thread but the center axle needs break wheel cylinders.
I found a part number of Wagner F79767 but have not found them
available locally. Is there a cross-reference.
Should I count on replacing the seal when I repack the bearings?

On Sat, Mar 3, 2018 at 8:21 PM, Richard Michelhaugh <

> With the air pressure released from the air bags the only 'weight' on the
> tire is the weight of the tire, wheel, brake assembly and bogie arm.
>
> A stiff bogie pivot could seem like extra weight.
> An off-normal shock could also add extra 'weight'. A gas-charged shock
> will help lift the wheel/bogie arm a bit.
>
> When the bogie drops down as airbags are deflated the shock is compressed
> limiting the travel downward.
> Make sure you are raising the coach enough to allow the shocks to be fully
> compressed.
> Don't let filled airbags push the shocks to full compression.
> Deflated them before the tires start to come off of the ground when
> raising the back end.
>
> Rick M.
> --
> 1974 26' Canyonlands
> aka "The General"
> Clinton, TN
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
If you add the "unsprung" weight up, it adds up to quite a bit. I haven't weighed the individual items, but i have lifted a few of them.
-Wheel and steel rim likely 60lbs (aluminum saves about 15lbs/wheel I believe)
-brake drum and hub likely 40lbs
-brake shoes,springs, cylinder, back plate and parking brake lines likely 20lbs
-Bogie arm (I've never lifted one) but likely 50-60lbs

Plus you still might have a few PSI left in the airbag.(area of air bag = pi*(r squared) so say 6" diameter = 3" radius x 3 = 9x3.14 = ~28 square
inches. so even 2 psi left in the bag will put a force of ~60lbs on the bogie arm)

So you can easily have a couple hundred pounds sitting on the tire.

The front axles (and back) may have Tru-Tracks on them which might be binding a bit and holding the bogie arm up. Or the bogie pivot pin might be
binding from lack of grease.

I put mine on blocks, for any extended storage. I use a small bottle jack to raise the bogie if I need to work on any of the rear wheels.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
You really need a jack hook and bottle jack if you own a GMC. BUY THEM.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
We supply them.

On Mon, Mar 5, 2018 at 5:30 AM, John R. Lebetski
wrote:

> You really need a jack hook and bottle jack if you own a GMC. BUY THEM.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
A gas-charged shock does not have an air line to it.
The shock insides are pressurized when manufactured.

Rick M.
--
1974 26' Canyonlands
aka "The General"
Clinton, TN
 
On Mon, Mar 5, 2018 at 9:27 PM Richard Michelhaugh <

> A gas-charged shock does not have an air line to it.
> The shock insides are pressurized when manufactured.
>
> Rick M.
> --
> 1974 26' Canyonlands
> aka "The General"
> Clinton, TN
>
> _____Rick, Gas shocks are charged with gas not air.

gas shocks are done at factory

>
__________________________________________
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
I used my jack hook and bottle jack and got 2 inches of space under the
tire and still could not pull the tire off. I used a bar between the ground
and the tire to move the bottom of tire out to brack the tire free. A
rubber mallet did not loosen it up. Real glad I was not trying to change
the tire on the side of a road someplace.

> On Mon, Mar 5, 2018 at 9:27 PM Richard Michelhaugh <

>
> > A gas-charged shock does not have an air line to it.
> > The shock insides are pressurized when manufactured.
> >
> > Rick M.
> > --
> > 1974 26' Canyonlands
> > aka "The General"
> > Clinton, TN
> >
> > _____Rick, Gas shocks are charged with gas not air.
>
> gas shocks are done at factory
>
> >
> __________________________________________
> > 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
John

Do you have a piece of spring under the arms to keep them from dropping
down? Maybe i missed something ...?

Mike in NS

On Tue, Mar 6, 2018 at 10:15 PM, Richard Michelhaugh <

> Charged with Nitrogen gas to be specific. :d
> --
> 1974 26' Canyonlands
> aka "The General"
> Clinton, TN
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS

Life is too short to hold a grudge; slash some tires and call it even !
 
No, I do not.
What damage should I look for because I did not use the spring?
I just had the coach high enough to get the wheels off the ground.

I inflated the bags, blocked up the center section and deflated the bags.
The center axle lifted off the ground a few inches on both sides. The rear
axle was on the ground but not by much on the left side but the right side
was about 200 lbs on the ground. I could not pull the wheel off and
thought it was because of the load. I put my bottle jack under the frame,
jacked it up enough so I could pull my blocking out, placed my jack
stand under the frame and moved the jack to the jack hook. I jacked it up
so I had 2 inches under the back tire and it still would not come off. I
tried a rubber mallet but a prybar finally got it free.

On Tue, Mar 6, 2018 at 6:31 PM, Kingsley Coach
wrote:

> John
>
> Do you have a piece of spring under the arms to keep them from dropping
> down? Maybe i missed something ...?
>
> Mike in NS
>
> On Tue, Mar 6, 2018 at 10:15 PM, Richard Michelhaugh <

>
> > Charged with Nitrogen gas to be specific. :d
> > --
> > 1974 26' Canyonlands
> > aka "The General"
> > Clinton, TN
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
> Michael Beaton
> 1977 Kingsley 26-11
> 1977 Eleganza II 26-3
> Antigonish, NS
>
> Life is too short to hold a grudge; slash some tires and call it even !
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
This is what I'm talking about but Ken Henderson said it better around
2014..

With either the OEM or upgraded systems, an important accessory is a piece
of steel bar stock, 3/8"x2.5"x12"-14" (some use a piece of an old leaf
spring). After raising the coach to where the suspension arms are level,
slide that bar into the bogie beneath the suspension arms so that each of
them is prevented from dropping lower. DUMP THE AIR from the air bags
before jacking further!!!. Now you'll only have to jack the coach about
1/2 as much as without that aid. The shock absorber will also be protected
from excessive loading.

Mike in NS

On Tue, Mar 6, 2018 at 11:25 PM, John Phillips
wrote:

> No, I do not.
> What damage should I look for because I did not use the spring?
> I just had the coach high enough to get the wheels off the ground.
>
> I inflated the bags, blocked up the center section and deflated the bags.
> The center axle lifted off the ground a few inches on both sides. The rear
> axle was on the ground but not by much on the left side but the right side
> was about 200 lbs on the ground. I could not pull the wheel off and
> thought it was because of the load. I put my bottle jack under the frame,
> jacked it up enough so I could pull my blocking out, placed my jack
> stand under the frame and moved the jack to the jack hook. I jacked it up
> so I had 2 inches under the back tire and it still would not come off. I
> tried a rubber mallet but a prybar finally got it free.
>
> On Tue, Mar 6, 2018 at 6:31 PM, Kingsley Coach

>
> > John
> >
> > Do you have a piece of spring under the arms to keep them from dropping
> > down? Maybe i missed something ...?
> >
> > Mike in NS
> >
> > On Tue, Mar 6, 2018 at 10:15 PM, Richard Michelhaugh <

> >
> > > Charged with Nitrogen gas to be specific. :d
> > > --
> > > 1974 26' Canyonlands
> > > aka "The General"
> > > Clinton, TN
> > >
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> >
> >
> >
> > --
> > Michael Beaton
> > 1977 Kingsley 26-11
> > 1977 Eleganza II 26-3
> > Antigonish, NS
> >
> > Life is too short to hold a grudge; slash some tires and call it even !
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
>
> *John Phillips*
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS

Life is too short to hold a grudge; slash some tires and call it even !
 
> This is what I'm talking about but Ken Henderson said it better around
> 2014..
>
> With either the OEM or upgraded systems, an important accessory is a piece
> of steel bar stock, 3/8"x2.5"x12"-14" (some use a piece of an old leaf
> spring). After raising the coach to where the suspension arms are level,
> slide that bar into the bogie beneath the suspension arms so that each of
> them is prevented from dropping lower. DUMP THE AIR from the air bags
> before jacking further!!!. Now you'll only have to jack the coach about
> 1/2 as much as without that aid. The shock absorber will also be protected
> from excessive loading.
>
> Mike in NS

Take a look at these pics:

http://www.gmcmhphotos.com/photos/g6509-blaze-orange-bogie-leaf-spring.html

JWID
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
Thank you Larry !

Mike in NS

> > This is what I'm talking about but Ken Henderson said it better around
> > 2014..
> >
> > With either the OEM or upgraded systems, an important accessory is a
> piece
> > of steel bar stock, 3/8"x2.5"x12"-14" (some use a piece of an old leaf
> > spring). After raising the coach to where the suspension arms are level,
> > slide that bar into the bogie beneath the suspension arms so that each of
> > them is prevented from dropping lower. DUMP THE AIR from the air bags
> > before jacking further!!!. Now you'll only have to jack the coach about
> > 1/2 as much as without that aid. The shock absorber will also be
> protected
> > from excessive loading.
> >
> > Mike in NS
>
> Take a look at these pics:
>
> http://www.gmcmhphotos.com/photos/g6509-blaze-orange-
> bogie-leaf-spring.html
>
> JWID
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS

Life is too short to hold a grudge; slash some tires and call it even !
 
I also have a pair of those in the coach painted bright orange because that happened to be the first can of bright colored paint that I found on the
shelf at the time. I seldom use them because I forget about them when jacking up the coach. I always disconnect the air line to the bags and find
that I can muscle the tires off and on without them.

It is a good idea if you can remember to insert them before jacking and remember to remove them when done. I often thought about attaching an orange
flag to one end of each one so it would be more apparent that it had not been removed when the repair work is done.

I also saw someone that used wooden wedges to do the same thing.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
As long as the pressure is off the air bags, all skipping the spring piece to block the bogies does is makes you jack it higher to clear the ground
with the tires. Won't hurt anything.

---johnny
--
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" - ol Andy, paraphrased
 
Now that's clever!
I like it.

I usually raise all the way up, then lower the coach onto some wood blocks and the tires will come off the ground, if not i toss a bottle jack under
the offending bogie and lift it until the tire is off the ground.
I like the leaf spring idea though!
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
The trick is to deflate the bags. They are more than capable of bending
1/2" thick x 3" wide steel plate, when filled with air.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

Now that's clever!
I like it.

I usually raise all the way up, then lower the coach onto some wood blocks
and the tires will come off the ground, if not i toss a bottle jack under
the offending bogie and lift it until the tire is off the ground.
I like the leaf spring idea though!
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

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>
> Not to hijack this thread but the center axle needs break wheel cylinders.
> I found a part number of Wagner F79767 but have not found them
> available locally. Is there a cross-reference.

John,

Try Rock Auto. Use the part number finder and do it soon. They are clearing them out.

Matt - who may be on there preferred list from the engine parts coming in.

--
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
 
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