Cab support failure

Matt Colie

Matt Colie

Well-known member
Aug 15, 2008
11,101
807
113
South East Michigan near DTW
One of my cab supports has a broken leg.

Those of us that have spent a lot of time in the "engine room" of GMC know of the three legged support that goes from the cab floor to an isolator on
the frame. I had never noticed any problem here, but when pulling the front frame yesterday, I have found a problem. At that time the assembly was
rolling nicely, when I noticed something wrong. The A/C clutch had carried along an unrecognized piece of aluminum.

That piece was discovered to be one of the legs of the right side cab support. Quite specifically the one the leans into the engine space. It
appears to be a part of the welded aluminum structure. It also shows a lot of wear on the surface that was supposed to be a part of the cab floor
structure.

Plan to repair is undetermined at this time, but if anybody has any experience here, I would love to hear about it.

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
 
> If It's a clean break I would just TIG it back in and maybe add a gusset while I was there welding.

Justin,

As good an idea as that is, The coach is in my barn and I sold off the SigmArk years ago.
I could weld the bottom with my torch (yes, I did used to weld Al with an O2-C2H2 torch) but up against the plywood floor might not have a good
result. I know what I would have charged to do this as a traveling welder and that is why I am evaluating cold repairs intently.

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
 
With that repaired and a new body mount in place she should have that new car feel restored.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Matt,
Please explain what years this support design is on.
There are lot of people that will be looking for this when they have a
newer units. It is a good idea to inspect the newer ones with the formed
Aluminum mount.

On Thu, Feb 1, 2018 at 3:30 PM, John R. Lebetski
wrote:

> With that repaired and a new body mount in place she should have that new
> car feel restored.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> 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
 
Jim,

I'm at the re-hab hospital twiddling my thumbs in between sessions with the physio terrorists working on my shoulder so I figgered
I'd give Matt a hand.

Reference Parts Book 78Z / Section 23 - Body / Page 23-2 / Figure 23-005 - Front Body, Cowl and Dash / Key 17 & 18.

Key: 17
P/N: 2001709
Description: SUPPORT ASSY - floor to body mounting RH (prior to Serial No. 6V100878) (repl. 698131)

Key: 18
P/N; 2001708
Description: SUPPORT ASSY - floor to body mounting LH (prior to Serial No. 6V100878) (repl. 698132)

Reference Maintenance Manual X-7525 / Section 2 - General Information / Page 1 / Figure 2 - Vehicle Identification Number

6 = 1976
V = Assembly Plant - Pontiac
100878 = Sequential Number

Therefore the "tripod" support was replaced with the formed support in 1976 starting with GMC S/N 100878.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Jim Kanomata
Sent: Friday, February 2, 2018 3:00 PM
To: gmclist
Subject: Re: [GMCnet] Cab support failure

Matt,
Please explain what years this support design is on. There are lot of people that will be looking for this when they have a newer
units. It is a good idea to inspect the newer ones with the formed Aluminum mount.

--
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
 
Rob,
Hope your going to be able to esape from there.
Take care, and thank you for your complete explanaton.

> Jim,
>
> I'm at the re-hab hospital twiddling my thumbs in between sessions with
> the physio terrorists working on my shoulder so I figgered
> I'd give Matt a hand.
>
> Reference Parts Book 78Z / Section 23 - Body / Page 23-2 / Figure 23-005 -
> Front Body, Cowl and Dash / Key 17 & 18.
>
> Key: 17
> P/N: 2001709
> Description: SUPPORT ASSY - floor to body mounting RH (prior to Serial No.
> 6V100878) (repl. 698131)
>
> Key: 18
> P/N; 2001708
> Description: SUPPORT ASSY - floor to body mounting LH (prior to Serial No.
> 6V100878) (repl. 698132)
>
> Reference Maintenance Manual X-7525 / Section 2 - General Information /
> Page 1 / Figure 2 - Vehicle Identification Number
>
> 6 = 1976
> V = Assembly Plant - Pontiac
> 100878 = Sequential Number
>
> Therefore the "tripod" support was replaced with the formed support in
> 1976 starting with GMC S/N 100878.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Jim
> Kanomata
> Sent: Friday, February 2, 2018 3:00 PM
> To: gmclist
> Subject: Re: [GMCnet] Cab support failure
>
> Matt,
> Please explain what years this support design is on. There are lot of
> people that will be looking for this when they have a newer
> units. It is a good idea to inspect the newer ones with the formed
> Aluminum mount.
>
>
>
>
> --
> 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
>
>
> _______________________________________________
> 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
 
Gotcha,

If that were the case (having not seen the break) I would probably use a structural epoxy (jb weld or better) and then attach a spanner plate across
the repair and rivet or bolt it in place.
No risk of burning down he coach and it would be plenty strong.

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
Matt, I would consider welding a properly shaped gusset to the bar while
off the coach, and the fastening the gusset to the aluminum cockpit frame
with screws. I used splice plates held with high-strength self-driving
screws to attach the rear body tub when I replaced the Adobe Posterior.

Then you can weld the lower point, which would be harder to fasten with
screwed connections.

Rick “who usually seeks the no-welding solution” Denney

> > If It's a clean break I would just TIG it back in and maybe add a gusset
> while I was there welding.
>
>
> Justin,
>
> As good an idea as that is, The coach is in my barn and I sold off the
> SigmArk years ago.
> I could weld the bottom with my torch (yes, I did used to weld Al with an
> O2-C2H2 torch) but up against the plywood floor might not have a good
> result. I know what I would have charged to do this as a traveling welder
> and that is why I am evaluating cold repairs intently.
>
> 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
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
Drive it to a welder and spend the money to have it welded with an aluminum
wire feed. Probably charge you the minimum labor charge of $50-$100. Tig
welding probably not the best platform considering access/ cleanliness.

Sully
77 eleganza 2
Bellevue

> Matt, I would consider welding a properly shaped gusset to the bar while
> off the coach, and the fastening the gusset to the aluminum cockpit frame
> with screws. I used splice plates held with high-strength self-driving
> screws to attach the rear body tub when I replaced the Adobe Posterior.
>
> Then you can weld the lower point, which would be harder to fasten with
> screwed connections.
>
> Rick “who usually seeks the no-welding solution” Denney
>

>

> > > If It's a clean break I would just TIG it back in and maybe add a
> gusset
> > while I was there welding.
> >
> >
> > Justin,
> >
> > As good an idea as that is, The coach is in my barn and I sold off the
> > SigmArk years ago.
> > I could weld the bottom with my torch (yes, I did used to weld Al with an
> > O2-C2H2 torch) but up against the plywood floor might not have a good
> > result. I know what I would have charged to do this as a traveling
> welder
> > and that is why I am evaluating cold repairs intently.
> >
> > 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
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> Rick Denney
> 73 x-Glacier 230 "Jaws"
> Off-list email to rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
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