replacing studs in the seat sliders

Joe Weir

Joe Weir

Member
Feb 13, 2013
743
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18
The mistress strikes again... Ok, so it was me.

So you know those guides at the big box store in the screw and bolt section that allow you to size your loose bolt?

The one at my friendly local Lowes said my seat slider nuts were 8x1.25. They weren't. The coach is a 76 - I figured it was a leftover from the
"lets convert to metric fad" of the early 70s where cars had mixed fasteners.

Pro tip: If you are unsure of your bolt size, don't get all fancy with nylon locknuts until you are sure of the size.

Yep, ruined 4 studs.

Anyone here ever had any experience replacing those studs? They seem to be pressed in.

If not, anyone have a spare slider for a trapezoid base to sell?
--
76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator, brakes, Sully airbags, fuel lines, seats, adult beverage center... those Coachmen
guys were really thinking about us second hand owners by including that beverage center...
Columbia, SC.
 
You mean you didn’t stop after you ruined the first one?

Sully
Bellevue

> The mistress strikes again... Ok, so it was me.
>
> So you know those guides at the big box store in the screw and bolt
> section that allow you to size your loose bolt?
>
> The one at my friendly local Lowes said my seat slider nuts were 8x1.25.
> They weren't. The coach is a 76 - I figured it was a leftover from the
> "lets convert to metric fad" of the early 70s where cars had mixed
> fasteners.
>
> Pro tip: If you are unsure of your bolt size, don't get all fancy with
> nylon locknuts until you are sure of the size.
>
> Yep, ruined 4 studs.
>
> Anyone here ever had any experience replacing those studs? They seem to
> be pressed in.
>
> If not, anyone have a spare slider for a trapezoid base to sell?
> --
> 76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator,
> brakes, Sully airbags, fuel lines, seats, adult beverage center... those
> Coachmen
> guys were really thinking about us second hand owners by including that
> beverage center...
> Columbia, SC.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Im not familiar with those bases, but do you have access room to run a Die over the mangled studs? Just cut new threads with a die and go a proper
size smaller nut and be done with it. Or get an 8 x 1.25 metric die and do the same. Provided they are not too bad the correct metric die should
clean up the threads.
--
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
 
Joe,

For future reference -- and those facing your similar "metric problem":
IIRC, NEW in '76 or later GM designs were metric. All previous designs, as
the GMCMH is, used SAE (inch) sizes. I don't think there was ever a metric
fastener on a GMC -- from the factory.

You ex-GM employees & other experts feel free to correct my ancient
memory! :-)

Ken H.​

> The mistress strikes again... Ok, so it was me.
>
> So you know those guides at the big box store in the screw and bolt
> section that allow you to size your loose bolt?
>
> The one at my friendly local Lowes said my seat slider nuts were 8x1.25.
> They weren't. The coach is a 76 - I figured it was a leftover from the
> "lets convert to metric fad" of the early 70s where cars had mixed
> fasteners.
> ​...
>
>
 
I've worked on coaches from 73 - 78. Never found one YET with metric
fasteners from the factory. Lots of Robertson heads on screws, which were
originally invented by a Canadian, but the sizes are U.S.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> Joe,
>
> For future reference -- and those facing your similar "metric problem":
> IIRC, NEW in '76 or later GM designs were metric. All previous designs, as
> the GMCMH is, used SAE (inch) sizes. I don't think there was ever a metric
> fastener on a GMC -- from the factory.
>
> You ex-GM employees & other experts feel free to correct my ancient
> memory! :-)
>
> Ken H.​
>

>
> > The mistress strikes again... Ok, so it was me.
> >
> > So you know those guides at the big box store in the screw and bolt
> > section that allow you to size your loose bolt?
> >
> > The one at my friendly local Lowes said my seat slider nuts were 8x1.25.
> > They weren't. The coach is a 76 - I figured it was a leftover from the
> > "lets convert to metric fad" of the early 70s where cars had mixed
> > fasteners.
> > ​...
> >
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Even when GM did start using a few metric fasteners, I recall they painted
them blue.

Rick “recalling a belt tension screw on an AC compressor in about 1980”
Denney

On Sun, Jul 22, 2018 at 2:57 PM Ken Henderson
wrote:

> Joe,
>
> For future reference -- and those facing your similar "metric problem":
> IIRC, NEW in '76 or later GM designs were metric. All previous designs, as
> the GMCMH is, used SAE (inch) sizes. I don't think there was ever a metric
> fastener on a GMC -- from the factory.
>
> You ex-GM employees & other experts feel free to correct my ancient
> memory! :-)
>
> Ken H.​
>
> --
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
> You mean you didn't stop after you ruined the first one?
>
> Sully
> Bellevue

There you go brandishing that dangerous logic...

I had taken the one existing nut to the hardware store, where the sizing "display" indicated the nut was 8x1.25. double checked - the sample would
not screw on to the sae studs.

Had I not gotten nylon locking nuts, I would have stopped right away. The resistance felt just like a nyloc nut.

--
76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator, brakes, Sully airbags, fuel lines, seats, adult beverage center... those Coachmen
guys were really thinking about us second hand owners by including that beverage center...
Columbia, SC.
 
> Im not familiar with those bases, but do you have access room to run a Die over the mangled studs? Just cut new threads with a die and go a
> proper size smaller nut and be done with it. Or get an 8 x 1.25 metric die and do the same. Provided they are not too bad the correct metric die
> should clean up the threads.

That might have to do, short of drilling out the studs and welding new ones in.

--
76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator, brakes, Sully airbags, fuel lines, seats, adult beverage center... those Coachmen
guys were really thinking about us second hand owners by including that beverage center...
Columbia, SC.
 
If you weee able to run the bits down with only the resistance given with a
nyloc you probably have not ruined the threads but maybe slightly rounding
them. I would re chase them all with the correct size/pitch nut grade 8
with lots of lube and see what u get.

Sully
Bellevue wa

> > Im not familiar with those bases, but do you have access room to run a
> Die over the mangled studs? Just cut new threads with a die and go a
> > proper size smaller nut and be done with it. Or get an 8 x 1.25 metric
> die and do the same. Provided they are not too bad the correct metric die
> > should clean up the threads.
>
>
> That might have to do, short of drilling out the studs and welding new
> ones in.
>
>
>
> --
> 76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator,
> brakes, Sully airbags, fuel lines, seats, adult beverage center... those
> Coachmen
> guys were really thinking about us second hand owners by including that
> beverage center...
> Columbia, SC.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> I would re chase them all with the correct size/pitch nut grade 8
> with lots of lube and see what u get.
>
> Sully
> Bellevue wa

If only I knew what that size was...

--
76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator, brakes, Sully airbags, fuel lines, seats, adult beverage center... those Coachmen
guys were really thinking about us second hand owners by including that beverage center...
Columbia, SC.
 
Joe,

I'd "lay dollars to donuts" they're 5/16"-18: 5/16=0.3125 &
8*.03937=0.31496

Those nearly-same diameters are what allowed you to make the mistake.

Since the 8mm is slightly larger than the 5/16", I'd go back with a
5/16"-18 die to clean them up.

​Ken H.

> > I would re chase them all with the correct size/pitch nut grade 8
> > with lots of lube and see what u get.
> >
> > Sully
> > Bellevue wa
>
>
> If only I knew what that size was...
>
>
>
 
Hi Joe,

5/16" is 7.9375mm (so 8mm for our purposes)

Your 8mm-1.25 nuts translate to a thread per inch of 20.32.

So, the standard Imperial size closest is 5/16"-18 (which is NC thread pitch).

So the die to try to clean the threads is 5/16"-18. Lots of cutting fluid. I will strongly recommend against trying to clean threads with a nut. This
is a very common die and should be readily available at well under ten bucks.

Good luck,

Tom
 
Thanks Guys.

I'll give that a try.
--
76 Birchaven - "Wicked Mistress" - New engine, trans, alum radiator, brakes, Sully airbags, fuel lines, seats, adult beverage center... those Coachmen
guys were really thinking about us second hand owners by including that beverage center...
Columbia, SC.
 
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