My sons and I are rebuilding a 1970 FJ40 and put axles on it from a 1976 in order to get the disc brakes. Unfortunately in my ignorance, I purchased axles that were setup for spring over conversion. I can't tell if there was a cut and turn done but I suspect it may be the case based on welds at the knuckles. I tried to go back to spring under but the pinion angle was terrible. I tried a cv axle from tom woods but have terrible vibration over 30mph. So my question is what does it take to go back to spring under? Cut and turn? Could I put axle shims in place in reverse orientation to help the pinion angle without affecting the castor? I could continue it spring over but it seems it will cost quite a bit as I would need traction bar, high steer kit, ?new leaf springs and bigger tires as I doubt my 33s that I have will look right with a spring over conversion lift. Thank you in advance.
Spring over back to spring under - what does it take? (1 Viewer)
- Thread starter tarpaigh
- Start date
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sounds like you need stock front axle housing. do you have the original axles? might need to just swap the disc outers to your 70 axle to make it work.
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pb4ugo
SILVER Star
^^^^^^^this^^^^^
Probably Swapping to disc knuckles on the old drum axle is your best bet. You'll want to service the trunion bearing and knuckles anyway.
Castor shims probably won't work on the soa axle. You might be able to get to the right caster angle , but the pinion will likely be off.
- Thread starter
- #4
That’s a great thought and I definitely had not thought of it. Mud is an awesome group. I have the original axles. I need to research changing the outers.
pb4ugo
SILVER Star
Search knuckle rebuild. @cruiseroutfit has knuckle rebuild kits. You'll use the disc birfs and axles.
the only hard part is grinding the inner part to make the disc birfield slide in. not really hard, but something to check while its 100% apart instead of figuring it out right as you try to slide them in and they won't fit.
pb4ugo
SILVER Star
A 76 should have small pattern knuckles and long birfs. They will probably fit fine. I would probably grind the balls so they could fit the larger birf for possible future repairs, but he would need a larger short birf to do so.
@tarpaigh , you can go to FAQ's at the top of the this section, scroll down to frt ends and read the 1st two threads for differences in birfs, knuckles and lockouts. Just so you know.
