Knuckle Shims (1 Viewer)

[NeverGiveUpYota]

I know this has been gone over a multitude of times but here I go...

Passenger side had a thick and thin on the top and a thick on the bottom.
Driver side had none on top and three thick on the bottom.

I’ve got the SST tool (@reevesci, via @Jaric00n) but I let anxiety get the best of me and just put back the shims the same way on the passenger side but now that I see this strange combo on the driver I feel it’s time to “man” up.

Prior to me tearing it down the truck has a 2” possibly more lift and sat on 35x15x12.5 tires w/ rims that had next to nothing for back spacing AND had 1/4” spacers installed (I was unaware) and my TRE dust boots were still getting eaten up by the rims.

Am I way off to wonder if the strange shim combos were used to help something that was way off w/ the trucks alignment?

Please enlighten me.
Felicity

 

[php74]

The shims on the bottom center it, the shims on the top set the preload. Look up how to check that with a fish scale.

If you have the centering tool, might as well use it. Although I’ve always put the shims back as they were removed or measured the thickness of them and replaced with new ones. It’s not uncommon to have 3 stacked up like you have.
Good luck!

 

[mwebfj60]

The bottom shims are used to adjust the vertical alignment of the knuckle housing (ends up a bit below center as per FSM). The top shims set preload. Technically both set preload as total shim...less shim thickness, higher preload...more shims, less preload.

I think a decent digital caliper is a necessity. A magnifying glass too.

When you measure distance ‘A’, don’t do it as per FSM picture from cutout to cutout. You need to measure from bottom of flange to bottom of flange.

It took me a couple hours and doing the complete set of measurements about 10 times to really get it figured out. It all makes sense after a while. You’ll get it figured out.

 

[OSS]

The shims were installed at the factory to center the knuckle as each knuckle coming off the the line was a little different. They 'should' never need replacing or changing. If one (unmolested) side has different shims than the other, that's fine.

 

[NeverGiveUpYota]

The shims were installed at the factory to center the knuckle as each knuckle coming off the the line was a little different. They 'should' never need replacing or changing. If one (unmolested) side has different shims than the other, that's fine.

How do I know what I found was stock? I tend to think someone was in there at one time...

 

[mwebfj60]

I had the same thing happen when I did the knuckles on the 62. Someone had put the shims wherever and they were different side to side. At the end, both sides ended up with the same combo on both sides and were within .002” of each other. The 60 was the same, both sides were the same top and bottom with even less overall difference.

I could see a slight vibration (4wd at speed) maybe if it’s not centered perfectly and eating up the inner seal but other than that, probably not a huge deal to be off center by a few thousandths. Total shim thickness for preload is probably more important.

 

[Prairie Swamp]

I don't believe those shims have anything to do with wheel alignment, lifts, etc. As the guys have said - they put the knuckle centered relative to the axle tube and provide bearing preload to keep the knuckle tight to the axle (not loosey goosey.)

 

[NeverGiveUpYota]

each knuckle coming off the the line was a little different

That’s what I did tend to wonder when I watched the video that @OTRAMM added on YouTube on how to use the SST for centering. Maybe something he said, not sure now. But really they were THAT different post casting huh? It’s amazing to me. Weren’t they’re poured in a mold? So top and bottom what, got filled some less some more so those two sides, top and bottom were finished that much off?

 

[NeverGiveUpYota]

Ok my mistake going overboard in my thinking on alignment w/ the knuckles.
I’ve just been really thinking on how different each sides shims are.... do I really put back the driver side so wacky as it is?

 

[OTRAMM]

The shims account for machining differences not just in the knuckle balls, but also the knuckles, and steering arms. All three were machined separately so they need a way to make up the differences.

 

[4Cruisers]

You can't always tell what came from the factory and what was changed by previous owners. I bought my '89 FJ62 from the son of the original owner. It came with a big stack of maintenance and repair invoices, mostly from dealerships. When I tore down the front axle to rebuild it for my '86 FJ60 project vehicle I noticed the knuckles had the flat and split washers mixed up randomly (should be flat washers on top and split washers on bottom). But there was no evidence in the invoices of any previous work done on the axle. It could have come that way from the factory for all I know. I decided, after consulting the forum, to reuse the shims as I found them.

 

[Cruiserdrew]

The axle tube is not cast in a mold. Just the balls, and then those are machined to spec. The axle tube itself has miles of welding on it and all of that welding heat can distort or warp it a bit. So the ball may not be exactly centered and the shims can help get back to the exact center. Use the tool! You have no idea what some past owner or shop did, nor do you know the housing hasn't been bent slightly by the hundreds of thousands of miles of pot holes, curbs, rocks, and bad behavior.

Use the tool. I have one of the Toyota OEM ones and actually it's pretty fun and you can get this setting within a few thousandths. I highly recommend you set it up properly.

The old rule of thumb is that one thick shim and one thin on top and bottom gets you close. And it works with a perfectly straight housing *most* of the time. So 3 shims on one side does not sound right. Take the measurements, set it perfectly and drive on. You may find your axle is a bit out.

 

[Prairie Swamp]

Bearing preload is touchy stuff. The steel isn't going to squish so the shims have to be just right. We're working toward .001 inch accuracy which is 1/3 thickness human hair.

Toyota and it's suppliers of bearings could have machined to aerospace tolerances but that lot of extra cost. Plus you don't know what you might get for bearings 30 years down the road. Hence the shims.

You adjust wheel bearing preload with the big nut. That isn't practical with the knuckle bearings I guess.

 

[NeverGiveUpYota]

But I didn’t use the tool on the first side. If I do now, doesn’t that mean I ought to break down the other side again?

 

[Cruiserdrew]

I'd use it on the side you're on now, and when you do this job again in 5 years, do both sides then.

 

[Tapage]

I guess leaking axle seal will tell sooner or later if all went good ..

 

[60Works]

'Yota,

Use the tool.

Use a good tool. There are a lot of home made and copy cat tools out there that are not accurate or need to be used with deviations from the FSM to compensate for bad machining.

Take the time know the 'why' for each measurement. Resist advice that such details don't matter to Land Cruisers. The knuckles precisely coordinate the center of the rotating axle with both the oil seal and the spindle bushing. The axis of the steering trunion needs to pierce through the exact center of the Birfield joint (at all angles of deflection in all 3 axis'). If its off even a little, it will wobble and eat away at the oil seal, diff and axle splines, and the guts of the Birfield. If its off a lot, it will bind and break at full articulation. All of these parts are expensive. This is worth getting right.

The housings did vary from the factory. But not much. As mentioned, Mud consensus seems to be that the normal OEM configuration is one thick on the bottom and one thick and thin on top. There are different thicknesses of 'thin' shims; .10, .20, and .30 mm. The thick shims are 1 mm.

Because your RH side follows this pattern, it is probably good and you shouldn't feel too obligated to tear it apart.

Your LH side is way off of normal and you should definitely investigate why. The axle housings tend to bend at the neck of the ball when abused by rough use or jumping. It's possible the PO tried to use shims to compensate for a bent housing. Given the dismal state of previous maintenance on your Cruiser, you should assume the worst until proven otherwise.


4Cruisers - If the cone and flat washers were mixed or a cone washer was missing on your 62 - its extremely unlikely to have come that way from the factory.

 

[Prairie Swamp]

I’ve got the SST tool (@reevesci, via @Jaric00n) but I let anxiety get the best of me and just put back the shims the same way on the passenger side but now that I see this strange combo on the driver I feel it’s time to “man” up.

Use a good tool. There are a lot of home made and copy cat tools out there that are not accurate or need to be used with deviations from the FSM to compensate for bad machining.

Sounds like she has loan of one of @reevesci tools. @mwebfj60 blazed the trail with this tool and has provided tips above (to me via PM as I have one of Jason's tools as well.)

We know you don't want to hear it Fel but you probably outght to take the first side apart. Your rig your call however.

 

[NeverGiveUpYota]

you probably outght to take the first side apart

Damn. Where’s the aghast face? Your killzing me man. Clearly you’ve not caught onto my non child free time added to the fact I’m working in my driveway?! I do hear you tho. It would seem jackass to only do one side w/ the tool. Ugh.

 

[FJ60Seth]

That’s a tough call. I’d probably leave the 1st side alone and finish the job so I could get some enjoyment out of the truck. If you end up having to redo it, it’s much faster the 2nd time.