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70 Series front axle

Discussion in '40- & 55-Series Tech' started by Degnol, Mar 25, 2004.

  1. Degnol

    Degnol

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    There is a 70 series front disc axle for sale, the perches have been repositioned for a '40 and it comes with a new seal kit. The overall width is about 2" wider than a stock '40.
    What do you think about this? My '40 is the old balljoint (no Birfs) axle which is near ompossible to convert, so I'd be looking at a newer axle, the mini parts to complete it and a lot of time.
    $750 plus about $150 shipping, no small decision. But I've got to get rid of the old single circuit braking system.
    Ed ???
     
  2. denis

    denis (O) toyota nut (O) SILVER Star

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    that doesn't sound cheap, unless it has an ARB or some other cool stuff in it. If you take your time I'm sure you could find quite cheaper...

    good luck ! :D
     
  3. Degnol

    Degnol

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    Thanks for the reply, but what do you think about the swap?
    I don't know much about the 70 series. I can look here locally IF somebody thinks it is a good swap.
    Thanks,
    Ed
     
  4. beanz2

    beanz2 Moderator

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    There are 2 kinds of leaf spring 70 series front axles: Pre-90 and 1990+. The pre-90 axle is very similar to a 60 axle but it's almost 40 series width (5mm wider). It uses the same standard pinion differential, brake calipers and same birfields. The '88 and newer has a reinforcing gussett on the bottom like on the FJ62. The advantage of these axles is mainly the increased caster (forgot the specs but it's in the Heavy Duty manual) so they should track better especially in lifted applications, the steering arms are beefier than standard 76-83 40 series arms. If these are locked, they use cable lockers.

    1990+ axles are the same width as the 85-89 axles, but they use high pinion diffs very similar to the 80 series. The knuckle ball is about 5 mm larger, so the seals are a bit different than the 40/60 kits. The birfield joint has an integral strengthening lip like the ring Bobby Long adds to 40/60 birfs but around the outside rim of the cup. The brake calipers and pads are larger, like the 92-96 4Runner brakes and ribbed for better heat dissipation. The housing cross section is square, like the 80 series front. Besides a deeper caster angle, the kingpin angle is flatter, so the steering centers better and the outside wheel camber is less when turning. If these are locked they come with an electric locker.

    Either type should give you better road manners than a 40 axle with minitruck knuckles. Unless you do a knuckle cut and turn.

    Dave
     
  5. Degnol

    Degnol

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    Thanks Dave, this is a high pinion, no locker and the seller said what you said. I know it is a lot of cash, but by the time I end up buying a later axle, the parts, etc, I could easily be close to that and like you said, not as good. I've only got about 1 1/2" lift(shackle reversal) and Being in KC, don't wheel much. My application is mainly DD, but I still want a DD with dependable brakes. I'm thinking about the no-power-assist Chevy S-10 dual master that SpaceGhost? has written a tech article on.
    Thanks for the info.
    Ed
     
  6. Degnol

    Degnol

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  7. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Get after it Ed!!!

    Good luck!

    -Steve
     
  8. Degnol

    Degnol

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    Steve, they said they'd even change out the pinion flange to fit my 3sp transfer, or at least include it, at no extra charge.
    So you don't think it is that much of a rip? When I do the math, then deduct the drive time I'd spend futzing with another axle, I come up ...."buy" ;)
    Ed
     
  9. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    I would be willing to bet that the companion flange on the other diff is round, and you could drill out your pattern on it pretty easily, and not have to worry about the flange...

    Seems like it would be fine...Do you have any pics?

    -Steve
     
  10. beanz2

    beanz2 Moderator

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    Here is a pic from GScruiserparts.com of such axle for you, Steve.. The one on the lower half of the pic:

    [​IMG]

    Dave
     
  11. Degnol

    Degnol

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    Thanks, Dave. What do you know about the tierod end compatibility? Am I going to have to have something made up? Would it be better to remove the idler arm and have it machined for the larger relay rod end?
    I will also go to a dual curcuit MC, so will have to change only front brakelines?
    Ed ???
     
  12. beanz2

    beanz2 Moderator

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    The TRE taper is the same as in the 80 series. I've never tried to put an 80 TRE into a 40 relay rod, but the thread size is M20 x 1.50. I don't recall what is the stock thread size for a 40 series.

    I would see if I can keep my rear brakeline if it'd save me from bending a whole new rear line. I'd still change the 9mm fittings to 10 mm to make parts easier to find later on. Right now, does the front and rear circuits branch off at the frame? Go to a self serve junkyard and get the L brakeline elbows and the 10 mm fittings off a Toyota car or truck.

    Dave
     
  13. Degnol

    Degnol

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    It comes off the master to the frame, runs to the left front passes around the front xmember to the rt front then back to the rears. My brakeline is real dinky, size wise and I'm wondering if having a larger line that serves the front and a smaller rear will become a proportioning problem. I want to use a S-10 non-boost MC
    Ed