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Converting old  ball-style pre '68 front end

Discussion in '40- & 55-Series Tech' started by Degnol, Jan 26, 2003.

  1. Degnol

    Degnol

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    I've got a '66 FJ40 with the old ball-style(pre Birfield) joints in the front end. If I want to convert to disc brake front end, do I need to swap out the entire axle assembly or can I change the inner/outer axles to the Birfield type then do a disc brake conversion?
    I see aftermarket kits for the later models, but not for the ball-type joints. &nbsp:Drums are working fine, but adjustments are very frequent, about every 500 miles.
    Also, does anybody run discs without going to a booster, just a double master cylinder? The truck is primarily a driver, I don't do any extreme wheeling and I run 31's. Thanks
     
  2. woody

    woody Internet Fireman Staff Member

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    Re: Converting old  ball-style pre '68 front end

    you need the entire housing, or at least a empty one to add stuff onto it.

    IIRC, Mike Smythe did a swap using a non-booster master cylinder. http://www.iei.net/~msmythe/
     
  3. Degnol

    Degnol

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    Re: Converting old  ball-style pre '68 front end

    Sounds like it will be easier and probably less expensive to find a '76-'79 front disc axle, go through it and then swap it out for my old one. Thanks for the tip on the dual master setup, looks doable
     
  4. zipp

    zipp

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    Re: Converting old  ball-style pre '68 front end

    My '70 had a single reservoir brake master, with no booster. When I went to mini discs in front, I installed a booster/master out of an '85 toy 1-ton. It has a slightly larger bore than regular pickups, so a little more fluid displacement. Had to drill some holes in the firewall, grind down a brace, run some brake lines... Not the most difficult task. Some time and money. But it worked like a charm! No more pumping the pedal. But when I started driving it, the booster was a little too sensitive for my likings. Something to think about, because SpaceGhost also didn't like the feel of the booster. I've got a bare housing from a 76 cruiser if you want- but you'd still need to get inners, birfs, knuckles.... Easiest thing to do would be to get an entire cruiser disc axle and just throw it under your rig.
    Zipp.
     
  5. cruzila

    cruzila

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    Re: Converting old  ball-style pre '68 front end

    If you can find a way to install an inner axle seal your old housing will work. It is not really worth the effort though. The best is to get a drum brake axle, 67-75 and put mini knuckles on it. THe cruiser disk knuckles are a little smaller in bolt pattern, have an 11mm stud and are prone to failure near the studs. Mini's have a 12mm stud and are stronger, not to mention the better locking hubs with cone washers.

    Cheers, Scott
     
  6. mixmaster

    mixmaster

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    Re: Converting old  ball-style pre '68 front end

    I did this conversion on my 68 fj40(with ball joints) a while ago. You have to pull out the brass seal out of the axle housing and then get a seal that fits. I could probably find what size I used if I looked. I did the mini disc brake conversion, using the mini booster. It probably would have been easier to just put a whole new axle under it because you have to replace the diff, inner axles and everything out. You have to swap out the diff to get the inner fine spline axle shafts to work with the mini birfield.

    Mike Bodrero
     
  7. ASHFAUQBUUT

    ASHFAUQBUUT

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    Did you ever find this seal number? I could use this information. :steer:
     
  8. 65swb45

    65swb45 Supporting Vendor

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    IIRC, nuclearlemon did. Try a thread search with her username and the word seal. Post the answer as well.;)
     
  9. 3_puppies

    3_puppies SILVER Star

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    I thought the seal # was listed somewhere in the links above,

    chicago rawhide # I think? FAQ?
     
  10. 3_puppies

    3_puppies SILVER Star

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    like you've never done that before
     
  11. cruiser_guy

    cruiser_guy

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    I did that, had the old axle housing machined for the OEM seal etc. etc. Long story short, not worth it!! Lot's of clearancing to do for the birf as well as the machining.

    I went out and bought a later housing and I'm going to use that. If a machine shop could get the seal area machined as per factory it might work. My problem is that it leaks oil past the seal/housing interface. Since it leaks there I'm not 100% sure the seal is EXACTLY centered, if the seal is not EXACTLY centered it will leak. The truck I have done this with has not even been driven yet and the felt wiper etc. is weeping slightly.

    As for "Cruzila's" comments the smaller pattern is only on the older trucks. Newer 'Crusiers are all the large stud pattern as are the mini trucks. I'm thinking the changeover is around '79 or so.