Front axle rebuild questions for the gurus…

[RattleCan]

First questions regarding trunion bearing preload.

Do most people re-install the shims that came out of there knuckle or go with the rebuild kit shims?

My trunion bearing preload pull-test was at 3lbs only before disassembly. Do I attribute that low number to worn bearings ( they were worn) or too many shims in the knuckle? I have on thicker and a thinner top and bottom I believe…

If I’m running 37 Inch tires i should shoot for around 15lbs on the preload pull test? If upon re-assembly I find 3lbs again after torquing top and bottom caps pull the thin shim top and bottom and try again?

My knuckles have cone washers on the top steering arms and also on the bottom caps. Did cone washers come on the bottom caps on all Toyota knuckles all years or are there year differences? If so, might help me identify my front axle vintage.

Discovered my Longfield chromoly hub gears don't seem to fit my Superwinch hubs. I assume they are designed for Aisin? If shopping for used Aisin hubs I can use any from Landcruiser, mini truck, 4 runner?

Thanks for any help or responses!

 

[pjohnson]

The shims are for centering the axle in the knuckle (and seal). Nothing to do with pre-load.

 

[RattleCan]

Are you not adding the shims to the bottom to center the knuckle, but the top shims under the steering arm are to add/subtract knuckle bearing preload ( I.e. if you remove shims it increases preload and if you add it decreases).?

 

[DangerNoodle]

I have both reused shims and replaced them, depending on their condition. I just make sure to keep the top and bottom cap shims separated. I haven't seen many bottom caps with cones, most of the ones that I have seen are just nuts and washers, with cones on the top. I would go for around 15 lbs, I can usually do it pretty closely by feel, and then checking. If for some reason it seems super tight to too loose, someone may have shimmed the knuckle wrong before, and you get to sort it out. Shimming does adjust preload somewhat. If it was loose before, it could just be that someone didn't tighten the arms down enough. The 15lbs is mostly for keeping the trunions happy and not too loose or tight, so don't recommend changing that. You may see that trunions are wearing faster with 37's due to the extra force applied to them when steering, if your wheel starts to feel clicky, it's probably the trunions. I've seen plenty of bad trunions, even with stock-sized tires.

Are your birfs coarse or fine spline? That's a good first step in determining year. Do you have OEM disks up front? There were a few years on long, fine spline birfs, but most of the time they are short, fine spline. I would guess that you probably have long birfs if your hubs aren't fitting and sitting flat on the spindle. I think most of the Warn hubs were for long birfs, but there are pretty rare Aisin long hubs. Very hard to find, though.

 

[Green Bean]

I have both reused shims and replaced them, depending on their condition. I just make sure to keep the top and bottom cap shims separated. I haven't seen many bottom caps with cones, most of the ones that I have seen are just nuts and washers, with cones on the top. I would go for around 15 lbs, I can usually do it pretty closely by feel, and then checking. If for some reason it seems super tight to too loose, someone may have shimmed the knuckle wrong before, and you get to sort it out. Shimming does adjust preload somewhat. If it was loose before, it could just be that someone didn't tighten the arms down enough. The 15lbs is mostly for keeping the trunions happy and not too loose or tight, so don't recommend changing that. You may see that trunions are wearing faster with 37's due to the extra force applied to them when steering, if your wheel starts to feel clicky, it's probably the trunions. I've seen plenty of bad trunions, even with stock-sized tires.

Are your birfs coarse or fine spline? That's a good first step in determining year. Do you have OEM disks up front? There were a few years on long, fine spline birfs, but most of the time they are short, fine spline. I would guess that you probably have long birfs if your hubs aren't fitting and sitting flat on the spindle. I think most of the Warn hubs were for long birfs, but there are pretty rare Aisin long hubs. Very hard to find, though.

Attached is a screenshot of parts diagram for a 1977 front axle assembly with corresponding parts numbers.. If I'm not mistaken, Toyota refers to the cone washers as "Dowels" This diagram shows them top and bottom. I believe the size of the knuckle studs increased to M12 in 1979.