Reaction arm issue

[hal stclair]

While going over the GMC after it's last trip I noticed that the reaction arm bolts holding the pivot brackets for the reaction arms had slipped. I
have been keeping an eye on this as there have been reports that this may be a problem area. I decided to try a simple fix, I hope, to mitigate the
issue. Here is how I approached it. If anyone has any suggestions, please speak up.
Hal
http://www.gmcmhphotos.com/photos/65-engine-swap/p65530-reaction-arm-bolt-anchor.html
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM

 

[Ken H.]

Hal,

I agree that the reaction arm pivot bracket is a problem area: During my
first long trip with the reaction arms installed (to the West coast &
back), I checked the bolts every couple of thousand miles and never found
them loose. But later, after becoming more complacent, I had one of the
bolts become so loose that inner "nut" turned and fell out of the bogie.
No damage resulted; the knocking during braking made me find the problem
quickly. But I have gone back to frequent checks and have found slightly
loose bolts a couple of times.

I don't understand your fix, unless you're preventing the bracket from
rotating relative to the bogie, hoping to eliminate bolt loosening. Is
that correct? Might it be worthwhile to install bolts horizontal through
your anchor into the pivot bracket? -- Or even to bolt the pivot bracket to
the bogie?

My theory has always been that the as-cast bogie's uneven surface would
wear into the smoothly machined bracket, thereby releasing the tension in
the bolt. Someone suggested that a possible remedy for that would be an
aluminum spacer between the two which would conform to the bogie's
surface. I haven't tried that. Are any of the steel-epoxies strong enough
to use between the bogie and the pivot bracket?

It's not, to me, a BIG problem, but I would like a more secure arrangement.

Ken H.

On Tue, Nov 13, 2018 at 8:05 PM Hal StClair
wrote:

> While going over the GMC after it's last trip I noticed that the reaction
> arm bolts holding the pivot brackets for the reaction arms had slipped. I
> have been keeping an eye on this as there have been reports that this may
> be a problem area. I decided to try a simple fix, I hope, to mitigate the
> issue. Here is how I approached it. If anyone has any suggestions, please
> speak up.
> Hal
>
> http://www.gmcmhphotos.com/photos/65-engine-swap/p65530-reaction-arm-bolt-anchor.html
> --
>

 

[hal stclair]

Ken, you're right in that I'm attempting to keep the nut from rotating. I'll still have to check the bolt for tightness but this should keep it from
moving. Unless the bolt would come all the way out, which would be a real stretch as the locking function of the nut SHOULD keep that from happening.
I hope that by keeping the slippage/movement of the bracket to a minimum it will improve it. I'd guess that a bolt could be run through the casting
and through the retaining bolt but I don't know if there is enough 'meat' on the nut to accomplish that.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM

 

[jim kanomata1]

We made change to our design few years ago to avoid this issue.
Rick Flanagan's coach has over 80,000 miles and we ispect it almost every
10,000 miles , so were on top of our designs,

On Tue, Nov 13, 2018 at 7:02 PM Hal StClair
wrote:

> Ken, you're right in that I'm attempting to keep the nut from rotating.
> I'll still have to check the bolt for tightness but this should keep it from
> moving. Unless the bolt would come all the way out, which would be a real
> stretch as the locking function of the nut SHOULD keep that from happening.
> I hope that by keeping the slippage/movement of the bracket to a minimum
> it will improve it. I'd guess that a bolt could be run through the casting
> and through the retaining bolt but I don't know if there is enough 'meat'
> on the nut to accomplish that.
> Hal
> --
> 1977 Royale 101348,
>
> 1977 Royale 101586, Diesel powered,
>
> 1975 Eleganza II, 101230,
>
> 1974 Eagle Bus 45',w/slideout,
>
> Rio Rancho, NM
>
> _______________________________________________
> 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

 

[johnny]

The setup Tom Pryor designed doesn't have the problem, the plate is a channel laser cut to fit the bottom of the bogie mount. This distributed the
load under braking. I still check the fasteners regularly but I've never found a loose one on two different installs.

--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" - ol Andy, paraphrased

 

[richshoop]

Not knowing anything about the application... but.... a castellated nut with cotter pin would prevent any nut loosening.

>
>
> Ken, you're right in that I'm attempting to keep the nut from rotating. I'll still have to check the bolt for tightness but this should keep it from
> moving. Unless the bolt would come all the way out, which would be a real stretch as the locking function of the nut SHOULD keep that from happening.
> I hope that by keeping the slippage/movement of the bracket to a minimum it will improve it. I'd guess that a bolt could be run through the casting
> and through the retaining bolt but I don't know if there is enough 'meat' on the nut to accomplish that.
> Hal
> --
> 1977 Royale 101348,
>
> 1977 Royale 101586, Diesel powered,
>
> 1975 Eleganza II, 101230,
>
> 1974 Eagle Bus 45',w/slideout,
>
> Rio Rancho, NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Larry Davick]

>
> My first thought, too, was a castlenated nut. Or loctight, or nylock nuts.

 

[Jim Hupy]

There is movement by the anchor against the bogie housing and that is where
the wear occurs. Then the bolt and nut lose their clamping load and the
anchor assembly moves. What Hal St.Clair has done should help. Time should
give us all the answer.
Jim Hupy

> >
> > My first thought, too, was a castlenated nut. Or loctight, or nylock
> nuts.
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> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>