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dually drums

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by R72K5, Feb 28, 2004.

  1. R72K5

    R72K5 Banned

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    how can you tell if a dually rear axle was originally a dually one or not ?

    also were the C20 dually crewcabs built on one ton chassis, or do they have spring pad spacing of a regular 3/4 ton and 1/2 ton ?
     
  2. u2slow

    u2slow 1/2 ton status

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    On a dually the drum is more cone shaped. The hubs stickout 4-5" instead of 2-3". The distance between the hub seal surface and backing plate flange is more like 6" instead of only 2".

    The C20 crewcabs (only seen these in SRW) use a 1-ton frame and 40.5" rear spring spacing.
     
  3. R72K5

    R72K5 Banned

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    so a c20 dually would be on 1 ton chassis just like the longhorns and duallies in 67-72?

    this 82 crewcab is a 20 according to model code and has a factory dually bed on it, and 14 bolt FF

    dunno leaf spring pad spacing, hmmmmmmmmmmmm
     
  4. u2slow

    u2slow 1/2 ton status

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    AFAIK, there was never a C20 dually /forums/images/graemlins/dunno.gif

    The 20-series crewcab kind of parallels the "longhorn" idea in the sense of a 1-ton frame in a 3/4-ton truck. However, the Longhorn was a C&C wheelbase that they made a custom bed for /forums/images/graemlins/wink.gif

    The 14bFF seems wierd. Dually pickups of that vintage should have a D70HD instead. Does the front use dually type wheels? /forums/images/graemlins/thinking.gif

    Does it have a ribbed pumpkin? If so, maybe a 92-newer 14bFF from a dually pickup or G30 cutaway van has been made to fit. /forums/images/graemlins/thinking.gif

    Another possibility is the dually wheels and box (or flares) were just added later. I wouldn't think a dually wheel would clear the SRW drum, but they could be the smaller 11" drums, did some grinding on the 13" ones, and/or chose their wheels carefully... Have you had the wheels off yet? Heck, maybe there's a spacer in there too... /forums/images/graemlins/ears.gif

    A WMS measurement on that thing would help too! /forums/images/graemlins/thumb.gif
     
  5. R72K5

    R72K5 Banned

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    yes it has the dually rotors up front and dually drums on axle, the drums are the dually 13 x 3.5" big honker ones, the bed is an original dually bed, has al the correct braces and everything for the fenders and wheel openings in the bed sides are not chopped out, they are factory, and also the wiring for the fender lights and grommets in the holes and everything are correct.


    only the big dooley trucks were dana 70 trucks, it was basiclaly a package, id have to open up the specs book pages i have for 81 gm trucks and type out all the info that would help explain this.

    R05 dual rear wheel conversion was avaialble on 20 series trucks since at least 1967, it exists from factory, i can type all that out i guess if someone really wanted ot see the info and the RPO codes

    the truck is a factory 40" pack to pack truck, and it is 3+3 cab instead of dooley package, when he got the truck it had old 60s 17.5" dual wheels on it, 17.5" were std equipment size wheels in 67-72 R05 years, 19.5" and some other sizes in between were available,

    i could explain it all if i got out the GM specs sheet books and went through them and typed out the info, its just matter of sitting down for long enough to do al that, but long story short is that dually rear whel conversion as available for c20 models for a fact but i dint know what all years because i just have 67-72 ones and 73 one and 81 one,



    the question i asked originalyl in this thread about how ot tell if an axle is a factory dually oen was pointless to ask, all i had ot do was pulla wheel and look at the drums lol and also measure to see if has the 1 ton 40" packs centers or not

    14 bolt 1 ton dually axles are common as heck, every 1 ton dually we come up with has always been 14 FF axle but all been chassis cabs and so 14 FF would be correct, the 82 crewcab might have originally been a chassis cab, in which wopuld explain the bed being a different original color(red) than the original color of the rest of the truck(white)

    bt then crew cabs might not have been available minus a bed, once again id have to look in the specifications sheets for 81 trucks that i have here

    thanks
     
  6. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    so a c20 dually would be on 1 ton chassis just like the longhorns and duallies in 67-72?

    this 82 crewcab is a 20 according to model code and has a factory dually bed on it, and 14 bolt FF

    dunno leaf spring pad spacing, hmmmmmmmmmmmm

    [/ QUOTE ]

    When you say the model code is that decifering the VIN or a badge on the fender?
    I haven't seen yet a C20 crewcab before.
    I have seen C20 dually but not crewcab.
    All the crew cabs I have seen are c30's or of course K30's like mine /forums/images/graemlins/grin.gif
    /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif
     
  7. thatK30guy

    thatK30guy 1 ton status Premium Member

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    C20 crew cabs are all over the place here. Never seen nor knew of any C20 duallys made.
     
  8. u2slow

    u2slow 1/2 ton status

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    They did make a C&C crewcab dually. This is a '91. I have more pics of it (rear, underneath, etc) on my other 'puter - which is down at the moment /forums/images/graemlins/frown.gif

    [​IMG]

    I would think one of these trucks with a dually bed would have the wheels tucked way in underneath. After all, there is ~10" axle width difference between the two duallys.

    The C20 crewcabs are very much a reality. My Dad has one - a '79 Scottsdale w/454; 8200lbs GVWR. Also seen a few in the 80-87 year range... mostly yellow though. I bet they were popular for certain fleet-type use. /forums/images/graemlins/thinking.gif
     
  9. R72K5

    R72K5 Banned

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    20 series duallies been available ever since at least 67 if not 63, again it is RPO option R05

    hmm that yellow crew has the same front tow hooks as my 83 k20 had

    interesting
     
  10. Eric M.

    Eric M. 1/2 ton status

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    Randy,

    Check for any contigencies regarding that RO5 dually code in your factory spec. books. I remember back in 85 talking to a dealer about ordering a new truck. The RO5 option was only available after the 1 ton upgrade. I can't remember any of the other codes associated with that conversation since I wanted a dually ... the only one that sticks is RO5.

    But then, that was 1985, a lot could have changed before (and after) then.

    Eric M.
     
  11. 4xcrazy

    4xcrazy 3/4 ton status

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    [ QUOTE ]
    On a dually the drum is more cone shaped. The hubs stickout 4-5" instead of 2-3". The distance between the hub seal surface and backing plate flange is more like 6" instead of only 2".



    [/ QUOTE ]

    This describes my 14bff to a T and it was removed from a '76 3/4 ton pick up. /forums/images/graemlins/thinking.gif
     
  12. R72K5

    R72K5 Banned

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    [ QUOTE ]
    [ QUOTE ]
    On a dually the drum is more cone shaped. The hubs stickout 4-5" instead of 2-3". The distance between the hub seal surface and backing plate flange is more like 6" instead of only 2".



    [/ QUOTE ]

    you sure it wasnt a C30 SRW pickup
    ?

    This describes my 14bff to a T and it was removed from a '76 3/4 ton pick up. /forums/images/graemlins/thinking.gif

    [/ QUOTE ]
     
  13. R72K5

    R72K5 Banned

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    [ QUOTE ]
    Randy,

    Check for any contigencies regarding that RO5 dually code in your factory spec. books. I remember back in 85 talking to a dealer about ordering a new truck. The RO5 option was only available after the 1 ton upgrade. I can't remember any of the other codes associated with that conversation since I wanted a dually ... the only one that sticks is RO5.

    But then, that was 1985, a lot could have changed before (and after) then.

    Eric M.

    [/ QUOTE ]

    chassic cab it has to be, 67-72 anyways, who knows in 70s and 80s, there wasnt even a k30 until 77 an the big dooley until early 80s

    trucks were slow to get new chassis models
     
  14. u2slow

    u2slow 1/2 ton status

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    [ QUOTE ]

    This describes my 14bff to a T and it was removed from a '76 3/4 ton pick up. /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    Just a thought...

    Are the shocks outboard (as a typical 3/4-ton) or inboard (as a 1-ton)? And what is the spring spacing? WMS measurement? Are the drums/shoes 2.5" or 3.5" wide?

    I know that on a 1-ton C&C dually (14bFF), the backing plates and leaf springs are only about 3/4" apart. Can't see how they could manage the wider 3/4-ton perch spacing (42.5" vs. 40.5") and also have room for a shock. /forums/images/graemlins/thinking.gif
     

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