fj40 knuckle swap

[tmckenziem]

Hey guys...........i just bought a front end out of a fj60 and plan on doing a knuckle swap on my 75 fj40! any body have any advice........i've never done it before.............but not an idiot!!!:fawkdancesmiley: ..........well maybe?! ha.....any way plan on putting in a true trac and some lower gearing while i'm in there and have not decided on some longfields or a birf eliminator yet..........any help would be apreciated.........by the way i'm gonna stay with a 35" tire while i'm there............and is there any body who can point me to some one to spring over these axles too?:corn:

 

[Tankota]

Talk to Bill, one of your FJ40 neighbors. Lives up the hill behind town.

As to your Q:
The knuckles should be the same, unless your going from drum to disc. I know some '75s had drums. Most had disc though.

I wouldn't bother with lower cruiser gears. ALot of money and not that much of a lower crawl ratio. 4.88s are about it unless you don't mind shaving ring gear teeth in order to fit the center pin into the carrier. 35s and 4.10s are fine usually (especially with a v-8 if ya got one). Go lower on the tranny by swapping in an SM with a granny gear.

Longfields 4 sho. Don't bother with the birf eliminator...its weaker than what you have already. I think Bob long still might just treat your stock birfs also. I've been running those for 5 years.

For your SOA, you have stock springs right now? If yes, those are work good. You gonna to PS at the same time? Got longer shocks yet? The front driveline slipyoke is right at the verge of being too short if you go SOA and shackle reversal (gonna do the SR at the same time?). I'd definitely recommend the SR while doing the SOA. You can also spin your front springs around for a better approach angle and a longer wheel base.

 

[tmckenziem]

I've got all the stuff for the sr ready to go. i will be going from drum fj40 to the disks on the fj60. I flipped the springs around about a year ago to get a little more clearance for my 33's.....wich still rub aweful still ........and almost have every thing together for the saginaw power steering.......thanks for the input

 

[tmckenziem]

also have the all pro high steer on the way for the spring over........when i get it done

 

[Rix]

I'm doing the same thing with truck knuckles.

 

[64FJ40]

The knuckles should be the same, unless your going from drum to disc.

The knuckles aren't the same. Even DB 75's (and up through '78) have the smaller bolt pattern for the steering arm. Very few options for aftermarket steering arms, and the smaller, weaker birfield.




Don't get birf-eliminators. If you really must upgrade, go for Longs. If it were mine, I'd just run the FJ60 birfs until I felt the need to drop $600 on Bobby's set. You will have to do some grinding on the end of the axle housing to fit them in.

Read up here:
http://internet.cybermesa.com/~chscully/front_discs.html
http://www.pirate4x4.com/tech/frontdisc/frontdisc.html


Really the only difference between the FJ60 swap and the mintruck swap is that the FJ60 rotors are thicker and vented versus the solid truck rotors (and the calipers are slightly bigger to compensate). The knuckles are identical.


Did you buy your knuckle rebuild kit yet? I highly recommend Kurt at www.cruiseroutfitters.com

I agree with Tankota about the gearing - stick with 4.10s. Not enough gain for the investment of going to lower R&P. Plus, if you ever screw up a diff, they're relatively cheap to just swap another stock one in rather than rebuilding with expensive aftermarket parts.

As far as tranny swaps, spring over and shackle reversal, more info than you probably need here: http://www.ih8mud.com/cruisertech.php




For me, the minitruck DB swap and GM rear disk swap (I did them at the same time) were probably the best 'driveability' improvement I've done to my Cruiser yet.

Eric

 

[tmckenziem]

eric thanks for the great info..........some of this i've seen........now this axle i bought does still have the steering arms on it.......i'm really stoked about getting disk brakes on this beast and getting it where i can romp on it with out fear........i know the ol' drums really suck to say the least..

 

[jeffs88toy]

I put some fj60 axles under a 1971 fj40 . the fj 60 is little wider it work out great.

 

[64FJ40]

now this axle i bought does still have the steering arms on it....

That's good. You'll need to use them until you do the spring over. I'm not sure about the tie-rod issue though. I don't remember when the sizes changed, so hopefully you can come up with something.

If you can't get something to work, let me know. Somewhere I have the info for a bushing that will allow you to run the earlier small TREs in the later steering arms.

 

[64FJ40]

I put some fj60 axles under a 1971 fj40 . the fj 60 is little wider it work out great.

Where did you put the springs? Did you outboard them on the frame? Notch the diff housing? Or just set up a really tall SOA spring perch?

 

[tmckenziem]

i'll get some pics of the build when i get on it an let every one know how it went.........i thought of useing the whole axle myself...........just don't know how outboarding the springs would work out?!

 

[Tankota]

Outboarding the springs means more sidehill stability (good at rimrock) but less articulation. Up to you which one means more to you.

 

[tmckenziem]

what all is involved in outboarding the springs ...........would love to see some pics if possible

 

[Turtle Bite]

You need to make new front spring hangers in the front and new shackles or mounts for the rear. I would just swap on the fj60 wipers out birfields and all, but the probably need new seals and bearings regardless. I would order your rebuild kit with wheel bearings and order the small birfield snaprings if you do decide to use the 60 stuff on your 40 axle. I think it is much easier to put IFS minitruck hubs or spacers on than it would be to do the fabwork for the whole axle swap.