Dave Tay wanted to dissect my rear full floating axle, he wants a full floating axle
completed with Toyota disk brakes and freewheeling hubs so he brought some
of his mini-truck disk brake parts to my house one early morning and...

FJ40 Full Floating axle, axle is surprisingly clean. The FF brake cylinder setup is very
much like my stock '75 FJ40 semi-floating axle.

Here is David Tay's dream FJ40 rear full floating axle setup: with mini-truck/LC brake caliber,
mini-truck/LC disk brake rotor, stock Land Cruiser Aisin freewheeling  hub The only
problem is he needs to figure out how!

FJ40 rear full floater spindle and mini-truck front spindle, we did some measurements
and they are almost exactly the same. Therefore we think we can use mini-truck
wheel bearings to rebuilt the axle, the back (inner) seal is the same too! It looks
like if you take the front mini-truck spindles and some how weld them  to your
rear existing semi-floating axle, viola, you have a full floating axle housing. This
is just our observations, we ain't no proffessional welders, let us know what
you think.

But, the mini-truck spindle is two about 2 threads shorter than the FF axle spindle.
And that's Dr. Tay's hands.

Here is how a mini-truck rotor fits onto the spindle, you can still see the FF
axle shaft stick out a bit, the axle shaft cannot go all the way in because the raised
surface for the rear seal, it's sticking up too much therefore interferes with
the spindle. The problem is the mini-truck hub is slightly shorter than the FF hub.

FF rear drum hub and mini-truck front hub/ rotor side by side

Another shot of the min-truck rotor fits onto the FF axle spindle. Notice that
on the FF axle, the brake backing plate is bolted to axle housing by 8 bolts instead
of only 6 bolts in the US semi-floating axle.

Here are some of Dave's thoughts on the disk conversion on FJ40 full floating axle:

1.  For Dave's conversion, custom axles are needed to work with the
freewheeling hubs
2.  There will be difficulty of getting a good seal between the axle
spindle and the axle shaft due to the fact that there is no space under
the locking hub for the thick FF sealing spindle nut.  A LCML member
"Rick D." mentioned to Dave in the past that FF axles after 1/79 have an
axle seal that is located inside the spindle, unlike the 12/78 and older
FF axles whose axle shaft seal is within the spindle nut like mine.
The newer FF axles, then, are the best candidates for a minitruck DB
conversion.

If you have any thoughts, ideas, or experiences on the disk brake conversion
on the rear of a FJ40 FF, please send me an email and I will add it to this page.

Thanks.
 

========================

And here are some of the emails we got from listers, I posted here as source of
information to help out the next guy who is doing it.

=========================

Message 1/63  From Herb Peyerl                               Sep 10, 00 05:33:22 AM -0600
 

To: tddo@cisco.com
Subject: ff rear db conversion.
Content-ID: <17403.968585601.1@lager.beer.org>
Date: Sun, 10 Sep 2000 05:33:22 -0600
Sender: hpeyerl@beer.org

>If you have any thoughts, ideas, or experiences on the disk brake conversion
>on the rear of a FJ40 FF, please send me an email and I will add it to this page.

Hi;

I'm building an FJ45 LWB which came with FF axles.  '77 I believe.

I converted to a disc brake setup on them and it was fairly straight forward.

The trick was to use the original FF hubs but retrofit the rotors to the
hubs by (in my case) grinding out the center of the rotor so it would fit
securely on the hub due to the FF hub having a more gradual shoulder vs.
the landcruiser front hubs.

Rob Mullen suggested taking the rotors to a machine shop and having them
cleanly take a couple of mm off the inside of the rotor.

Other than fashioning some brackets to hold the calipers on with, you should
be able to bolt the rest together.  For brackets, I had a couple of dead
front disc brake knuckle housings so I cut off a chunk of the knuckle where
the calipers bolted on and turned those into my brackets.

I briefly considered putting free-wheeling hubs on but decided there was
very little benefit for the amount of trouble it was going to be.  Not to
mention that the FF hub is a good 20mm longer so the hub would stick out
20mm further than it does on the front and I didn't want the hub catching
trees or rocks.
 

hth.

=========================

Here is a quote from an article named "Chris Olsen's Willy's Jeep"  from this website:

http://www.bc4x4.com/tech/fv/2000/colson/colson.asp

"Getting back to the axles, the FJ45 full floater's drum brakes were tossed in favour of a set of discs from a Toyota pickup. Chris came up with a
     simple way to mount the S16 dual-piston calipers from a 2wd Toyota pickup. He cut up the mini-truck's knuckles so that all he had left was the
     caliper brackets and a portion of the knuckle to which the spindle attached. This spindle bolt pattern matched the FJ45's pattern perfectly. He
     attached the left knuckle to the right axle end and vice versa. This was a lot faster than fabbing a custom part and way cheaper than buying an
     aftermarket piece. "

Picture is from the same article.