School me on a 40 disc conversion

[In2cruisers]

A buddy is trying to build a parts list for a 60 knuckle swap on to a spare 40 axle.
Couple questions....the 40 axle is of unknown year (not ball and claw) are the inner axles compatable with later Disc birfields as far as spline count? if not ??

Diff - spline count? years?
Inner axle - spline count? years?
birfield- spline count?

 

[Tigerstripe40]

A buddy is trying to build a parts list for a 60 knuckle swap on to a spare 40 axle.
Couple questions....the 40 axle is of unknown year (not ball and claw) are the inner axles compatible with later Disc birfields as far as spline count? if not ??

Diff - spline count? years?
Inner axle - spline count? years?
birfield- spline count?

As long as the inners are the fine spline axles (they should be IIRC, the course spline inners were only available for a year or 2). they will mate into the disc brake birfields.

Diff side of the inner is 30 spline, Birfield side is 27 spline.
The stub of the Birfield that engages the hub is 30 spline as well.

So if you have the appropriate inner axle shafts, you need the birfields, knuckles, steering arms, spindles, bearing hubs, rotors, calipers, and locking hubs. There are some other hard and soft lines necessary.

 

[edwjmcgrath]

Here are my notes to myself when I was doing mine. Hope this is helpful:

Coarse spline 69 thru 75, fine spline thereafter. Birfield stub axle length reduce by about 3/8" starting in 1979, so 76-78 are oddball longer disk brake birfs. FJ60, 79+ FJ40, and mini truck birfs are interchangeable. Shorter birfs are stronger and slightly larger in diameter than the 69-75 birfs, however a 69-75 axle housing can be easily clearanced for the larger diameter.

Wheel hubs and rotors: 76-78 Fj40 rotor bolted to hub; 79+ fj40, FJ60, Solid axle Mini rotor attaches to wheel hub with wheel studs. The rotor/wheel hub assemblies are interchangeable as a set. The later (wheel studs thru rotor) rotors are considerably cheaper than the earlier bolt on versions, however, they are more work and expense to change out because wheel lugs have to be removed and replaced, typically with a press. Mini rotors are not vented, but 4runner rotors are.

 

[In2cruisers]

What he has is a 40 axle of unknow year...(post ball and claw)
Axle inner and outers from same
60 series knucles and hubs
40 series disc birfields

I know after looking today that his existing axle, the birfield is course...does that say anything about the inner shaft to birfield splne??