'81 C30 Dually rearend identity??

Discussion in 'Trucks and Trailers' started by OuTLaW, Dec 27, 2000.

  1. OuTLaW

    OuTLaW LawnSite Member
    Posts: 14

    I just aquired an '81 C30 crew cab dually. The thing is a complete gut jub and I have little to work with. The rear end on it is a 14 bolt but seems too narrow. I need to find the correct width rear for it. The local pick a parts have very few duallys that come through there so here is my ?. Is there another rear that can be swapped that has the correct width? perhaps off a C20 or something? I'm not sure what this one came off but is a 14 bolt. The inner tires rub on the leaf springs so it seems to be incorrect or ?... Is there some sort of interchangability between C20 and C30 with different drums or is the dually rear a 1 of a kind? Please help, i've found nothing on the width of these anywhere on the net. Just lots of gear ratios and ring sizes.

  2. cowboy

    cowboy LawnSite Member
    Posts: 84

    well sounds like you need differnt backspacing on your wheels, your backspacing is to great, get some wheel with less backspacing and that should solve your problem,
    a lot cheaper than a new axle!

  3. 4x4k20

    4x4k20 LawnSite Member
    from ga
    Posts: 148

    a true dually pickup with the wide fiberglass fenders does have a wider rear axle they are the only ones that came with it the regular 30 series cab and chassis used a narrower one with dual wheels some has swaped yours i dont know the measurements but they are wider to compensate for the wide fiberglass fenders
  4. OuTLaW

    OuTLaW LawnSite Member
    Posts: 14

    4x4: Thats what I was afraid of. Guess i'll just have to look for one that was on a true dually. They are few and far between at the wrecking yards so I was hoping they'd be interchangeable or atleast some part I could change out. The axles and tubes make it a little more difficult to repair it. The wheel backspacing won't help since it is a dually, if I change the backspacing the inner rim would hit the outer. There is about 3" difference between where the outer wheel edge is and the inner edge of the fender. Also the inner tire hits the bed edge. Anyone in so. cal. looking for a good 14 bolt rear end???? Hopefully I can find one at a wrecking yard since they're $25 complete drum to drum. Guess I can measure the one in it and add 6" to that # and look for it, unless someone knows if they were all different sizes?
  5. mike reeh

    mike reeh LawnSite Member
    Posts: 229

    Where is So. Cal are you? Im in the north county inland area, like escondido, etc. (san diego county)

    Ive seen dually rear ends in the junkyards before.. they're definately not dime a dozen but if you keep up, you'll find one.. Your best bet will probably be to get one off a later model truck that comes in..

    Just recently I saw an advertisement for a company the specializes in stuff to do just what you need, convert a rear end to dually, and vice versa, and they had tons of options for wheel offsets, that was their game. Unfortunately I didnt have a need for their product so I think I just kept walking :( I know that doesnt do you much good but you might try searching the net for something that like, "convert to dually" or something, maybe you'll find em.

    good luck. might try calling Vista Driveline in vista, ca.. they are real good there. expensive, but good. they will probably have the info you need.

    mike reeh
  6. Alan

    Alan Member
    Posts: 1,185

    It's not wider to compensate for the fenders, it's wider to accomodate the 49" wide pickup bed between the inner wheels. The fenders have to be so wide to cover the outside wheels.
  7. OuTLaW

    OuTLaW LawnSite Member
    Posts: 14

    Thanks for the info guys. I've found more on this lawn board than anywhere else on the web. You guys have been a great help. I'm gonna keep an eye peeled for a while on this one. Mike: I'm in Fontana just about 45 mins from you. There are about 10-12 wrecking yards around here so i'll look around this weekend. Unfortunately the boys at Hot Rod MAgazine seem to like publishing my closest yard PAP in Ontario, CA for their junkyard jewels. Since they started those it seems like the V8 selection in pretty picked already and i'm sure it doesn't help that Scottys truck and 4x4 wrecking yard is next door. They probably get first dibbs on the good stuff. I really hate to pay their inflated prices but may come to that if the goin gets tough.

    Thanks again for all the info guys!
  8. crw432

    crw432 LawnSite Member
    Posts: 14

    The c30 did come as a single rear wheel application, however I have a 1983 model and am running the regular dual wheel setup and have about 2 inches clearance on the springs, was not worried about bed clearance cause I use a flatbed, but I did "tub" the original bed (cut out about 3 inches on each side for clearance) and it works great. The "look" is very cool with all that tire sitting under the bed, looks like a drag racer with big slicks. I did also swap out the front with another dually parts truck so I could run dual style all the way around. It has 245/70-16's all the wat around. Sorry but the rear end in my parts truck is toast. I have a buddy with a C30 narrow rear end who is in process of installing a Dana 60 dual rear end off of an 79/80 Dodge b30 motorhome, it is mounted with little work, just had to cut and weld spring supports, looking for brake conversion fittings right now, but has driven it around the yard.
    Check your build sheet in the glovebox if you have one it will tell which rearend you have, and if it was a real dually it will show the optional rearend.

    1983 C30 3+3 454 450+ HP (HERE is the power...stroke it!!!!)
    1997 Dodge 3/4T 4x4 V-10
    1978 Blazer 502 Cu In....Monster

    [Edited by crw432 on 01-05-2001 at 07:58 AM]
  9. OuTLaW

    OuTLaW LawnSite Member
    Posts: 14

    Thanks for the info Craig. I was able to obtain a rear end off a C30 flatbed @ pick a part... I haven't been able to get it in yet and it better work... Damn thing is like 400lbs. The old rear hat the drum backing plate right next to the spring perch so the tires would rub. The bed on it was replaced by the previous owner and is obviously not the one it came with, big blue stripe on the bed only! When I checked the VIN the digit showing what type of bed was on it. It just says "unfinished"??? Is this normal for a 3+3 or did it really leave the factory as a bare chasis and cab?

    The new rear has about 3" beyond the spring on each side and hopefully will fix the problems. Now I just have to sell the old rear. Anyone looking for a 3/4 ton 14 bolt in so. cal.?????

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