1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Knuckle swap?

Discussion in '40- & 55-Series Tech' started by bad_religion_au, Nov 1, 2003.

  1. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    2
    Joined:
    Apr 24, 2003
    how hard a job would it be to swap fj60 knuckles onto either my 76 fj40 front axle, or my 80 hj45 axle (fine 30 (i think) spline drum brake)??
     
  2. Cruiserdrew

    Cruiserdrew SILVER Star

    Messages:
    14,703
    Likes Received:
    3,191
    Joined:
    Mar 15, 2003
    Location:
    Sacramento, CA
    It would be especially worthwhile on the '76 because you get to move up to the more standard Birfield and steering arm bolt pattern. You would have to swap everything though-knuckle, Birfield, spindle, steering arms, brake caliper, hubs and lockouts. Did the '76 FJ40's down there have drums or discs? If discs, I might do the drum braked truck. This would be a tedious swap, but not technically hard.
     
  3. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    2
    Joined:
    Apr 24, 2003
    76 has disks, the 1980 45 has drums. not sure if it (the 1980) has the more standard birf, or the weaker fine spline birf. i was considering tearing down the front end and doing all the seals etc anyway, and also on the lookout for a junked 60 for stuff (2f/3f/2h or 12ht (i think) rear springs, shackles and spring hangers.) and was wondering if the other stuff would be a good swap. the 76 40 would see more harder wheeling (the 45 only has 31's) and the drums just all got redone, so it stops really good. and one of the free wheelers on the 76 is busted.

    would i have to grind the birf to fit? i've heard this done for one knuckle swap, unsure of which one.
     
  4. Bret

    Bret

    Messages:
    2,286
    Likes Received:
    168
    Joined:
    Oct 31, 2003
    Location:
    MT
    I just finished doing the driver side tonight and it went very smoothly, I have a 76 FJ-40 and got two knuckles and steering arms from a salvage yard. Everything bolted right up. I didn't have to pull the anything out Same bearings, spindle, gaskets, everything. The steering arm is considerably beefier compared to the 40 arm. Did I miss something?
     
  5. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    2
    Joined:
    Apr 24, 2003
    ohh i forgot to mention that i may use the wrecked 60 for power steering parts too, so i guess that would help decide to use the knuckles :)

    would i need the inner axles as well, or will 60 birfs hook up to my inner axles?
     
  6. Cruiserdrew

    Cruiserdrew SILVER Star

    Messages:
    14,703
    Likes Received:
    3,191
    Joined:
    Mar 15, 2003
    Location:
    Sacramento, CA
    The 60 birfs would work on the existing inner axles. The 40 and 60 share the same short side axle shaft, the long side only is different. As far as the decision making, if the 40 is broken, fix that with the FJ60 parts. I wouldn't grind the birf, but you might have to grind the inner part of the ball a few thousands.
     
  7. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    2
    Joined:
    Apr 24, 2003
    ok, so considering the inner axles will work together with each other, that means the diffs will be interchangable (science student here remember, not a mech)?

    i know they have 3.70 ratios, compared to my 4.11 in the 76, but is that just one gear, and the rest can be swapped, keeping the 4.11 ratio?

    also if in the future i looked to doing a disk swap on my hj45, i could use the knuckles off the 76? with a rebuilt free wheeling hub?
     
  8. Cruiserdrew

    Cruiserdrew SILVER Star

    Messages:
    14,703
    Likes Received:
    3,191
    Joined:
    Mar 15, 2003
    Location:
    Sacramento, CA
    There should be no need to change the diff at all. Since this is all front axle stuff, the axle shafts will slide right out-leave the diff alone, but if you want to swap the diffs as well, they will bolt right in. In fact, I've got '78 diffs in my '84 FJ60.
     
  9. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    2
    Joined:
    Apr 24, 2003
    [quote author=Cruiserdrew link=board=1;threadid=6992;start=msg58099#msg58099 date=1067789718]
    There should be no need to change the diff at all. Since this is all front axle stuff, the axle shafts will slide right out-leave the diff alone, but if you want to swap the diffs as well, they will bolt right in. In fact, I've got '78 diffs in my '84 FJ60.
    [/quote]

    my idea was as follows. i have a bad rear diff in the 76 (haven't looked yet, probably pinion bearings) i was thinking that if i got a parts rig, i could swap in the 60 series rear diff. but i want to retain 4.11 diff ratios. what parts need to be swapped between diffs to do this, and will it require backlash and preload settings, or should i just get off my ass and get my mate to help do the bearings.
     
  10. Cruiserdrew

    Cruiserdrew SILVER Star

    Messages:
    14,703
    Likes Received:
    3,191
    Joined:
    Mar 15, 2003
    Location:
    Sacramento, CA
    Either way you are looking at a diff rebuild in the rear. This isn't something I would do by myself. Setting up diffs is one of those skill things most of us don't have. You will also need new bearings for which ever diff you rebuild. I just had a diff rebuilt-$125 for bearings+$150 to set it up plus I needed a new cross pin $20. So you are looking at about $300 US unless the labor is cheaper down under. If you have a friend who knows differentials, you have a chance to learn something useful. Good luck
     
  11. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    2
    Joined:
    Apr 24, 2003
    yeah my friends done 3 of his own in his hj75, and was a diesel mechanic,... now a plumber.