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'72 drum to disk

Discussion in '40- & 55-Series Tech' started by OlympiaFJ60, Jan 4, 2004.

  1. OlympiaFJ60

    OlympiaFJ60

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    I want to put disk on the front of a '72 FJ55 and have access to both 70 and 80 series axles. Will the knuckls/bifrields work on the '72 axle housing?

    Also, do both the '72 and '93 Cruisers have 4.10 diffs or is one 4.10 and one 4.11?

    Thanks,

    Brandon
    Olympia, WA
     
  2. cruiseroutfit

    cruiseroutfit Supporting Vendor Moderator

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    The 70 series might work, needs to be the older 9.5" ring gear, otherwise you have the same front end as the 80 series (I think, ot did the 70 have the 8" diff but reg. knuckles?)

    The 80 series will NOT work...
     
  3. beanz2

    beanz2 Moderator

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    Pre-1990 70 series have the same knuckles and the same sized ring gear. 1990-on 70 axles have the same high pinion front diff as the 80 series and a slightly larger knuckle but not 80 series-sized yet. The parts will appear to fit the 40 housing but it is some 5 mm larger.

    I'd think of swapping the entire 70 series axle into the 40 since the caster is better, the steering arms, brakes and birfields are bigger. Since the spring on the 40 is thinner (across the leaves, not the spring pack thickness) I'd try to use stock or custom bent U-bolts and 70 series spring plates without moving the spring perches. These are square shouldered U-bolts like used in the 60 series and go in front and behind the axle, not around the housing like in the 40.

    Dave