93 FJ80 Steering Knuckle Issue

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Sep 17, 2017
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Texas
I am in the process of repairing my leaky front axle seals, and at the same time address the sloppy steering of my 93 FJ80. I replaced the axles, Birfields, all bearings, and seals. During the re-installation I had trouble shimming the steering knuckle to give me the 5.6-10 lbs pull the service manual calls for. My cruiser has always been a bit squirrely at highway speeds, and one video I watched said if you have a lifted Cruiser and larger tires the correct tension is 12 to 15 lbs. When I add any shims at all my knuckle is basically loose, no play, but no resistance either. I removed the shims all together on re-assembly and got about 7 lbs resistance. I did not measure the distances to verify the axle is centered, since adding any shims exacerbated the steering issue. I reassembled everything according to spec and drove the truck back and forth to work once, about a 50 mile round trip. Parked it in garage for a few days and noticed both seals are leaking my fresh gear oil onto the floor. I’m assuming my issue is the axle is not centered and wiping out the seal.

My question is does anyone have any ideas as to why my knuckles don’t want to shim properly? How do you fix it? It was the same issue both sides. Would seem unlikely the knuckles on both sides are bad or the axle housing is the issue (god forbiod), so I’m guessing there is something I’m missing. All of the original shims were in the top of the knuckle, none in the bottom. Can the pieces that are shimmed be collapsed slightly like what happens to a crush sleeve?
 

dirtyboots

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Inner axle seal backwards would be my first guess, especially if it's leaking more now than before you serviced the knuckles.
I did not measure the distances to verify the axle is centered
If I understand what your saying that's not a thing. The housing is bent, and/ or the axle is bent, and/or the birfield is jacked, AFAIK, knuckle shims won't displace axle alignment that will affect the seals (unless you tried really hard and even then I dunno) good luck, this is mud and an expert will be with you shortly
 
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If I remember correctly, I put the old shims back in their original spots. torqued to spec, and didn't have a problem with mine. I believe you only replace shims if there's an issue with yours.
As for the leaking, I'm with dirtyboots on this. Something with the axle seals is wrong. It's possible the housing is bent, sure, but it's not incredibly common.
 
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Poor handling is not the result of improper preload on the knuckle bearings. If there were shims when you took it apart, put the shims back where you found them.
Adding shims will decrease preload. Removing shims will increase preload. Once all shims are removed, you cannot increase preload beyond that point without machining the housing.
Your poor handling is likely from too little caster. An alignment shop should be your first step.
 
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Inner axle seal backwards would be my first guess, especially if it's leaking more now than before you serviced the knuckles.
I did not measure the distances to verify the axle is centered
If I understand what your saying that's not a thing. The housing is bent, and/ or the axle is bent, and/or the birfield is jacked, AFAIK, knuckle shims won't displace axle alignment that will affect the seals (unless you tried really hard and even then I dunno) good luck, this is mud and an expert will be with you shortly
Inner axle seals are not backwards. I‘m not even sure how you would do that. The Otram video shows the tech checking the distance of the axle to the housing to verify it is properly centered. Yes, I understand most videos just showed replacing the shims that were found and going on without a problem, but ignores the tech service manual instructing you to check the tension, which is the issue. Thanks for the suggestions. I wa s careful when I reinstalled the axles to make sure I did not damage the spring in the seal.
 
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If I remember correctly, I put the old shims back in their original spots. torqued to spec, and didn't have a problem with mine. I believe you only replace shims if there's an issue with yours.
As for the leaking, I'm with dirtyboots on this. Something with the axle seals is wrong. It's possible the housing is bent, sure, but it's not incredibly common.
Yes, most videos just show you replacing your shims like you found them and moving on. If you go by the tech service manual you check the tension. This is where I have my issue. Getting the preload correct, using any shims at all is impossible.
 
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Poor handling is not the result of improper preload on the knuckle bearings. If there were shims when you took it apart, put the shims back where you found them.
Adding shims will decrease preload. Removing shims will increase preload. Once all shims are removed, you cannot increase preload beyond that point without machining the housing.
Your poor handling is likely from too little caster. An alignment shop should be your first step.
I’m not certain my poor handling is the result of a lack of preload, but if follow the tech service manual it is impossible to get the correct preload using any shims at all. This tells me something is amiss. I have had the handling issues with the truck since I purchased it, and since I had never owned a lifted Fj80 I wrote it up to just the vehicle. I have had the alignment done, but thats not saying I couldn’t benefit from additional caster.
 

dirtyboots

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I‘m not even sure how you would do that.
Let it be known, for the record I have installed a seal backwards. My uncle used to say I could break a steel rod so there's that. It's so odd that with no shims you can't get to the minimal resistance spec on the knuckles. And have leaky seals.
Is your scale reading kilos instead of pounds or any possibilities the scale / tool your using has an issue?
 
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I’m not certain my poor handling is the result of a lack of preload, but if follow the tech service manual it is impossible to get the correct preload using any shims at all. This tells me something is amiss. I have had the handling issues with the truck since I purchased it, and since I had never owned a lifted Fj80 I wrote it up to just the vehicle. I have had the alignment done, but thats not saying I couldn’t benefit from additional caster.
The lubricants of today are far better than 25 years ago.

Depending on what grease you use in your trunnions, you may never get proper fish scale settings.

I too, have tried to follow the FSM to the letter and found that some things don't work.

On the wheel bearings, I used Lucas Red-N-Tacky 2. I cranked the bearings down as much as 65 LB-FT trying to get to the fish-scale readings and I never achieved the correct setting.

I finally went with what I know and now set them to 35 LB-FT.

So, install the shims where they were, check for no play, and go to the next step.
 
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What kind of trunions you got?
Trunnions are factory. They appear to be welded to the axle housing, so it doesn't appear they can be replaced without welding, and who knows what kind of procedure it would require. I am wondering if the trunnion bearing caps can become compressed to the point they are a few thousands shorter than when they were new? I had similar issue once replacing rear wheel bearings where there was a " bearing spacer" in the FSM that eventually a machinist told me was a "crush sleeve" that needed to be replaced. When I went to the dealership to get a new one, it was almost a 1/16" taller than the old one.
 
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The lubricants of today are far better than 25 years ago.

Depending on what grease you use in your trunnions, you may never get proper fish scale settings.

I too, have tried to follow the FSM to the letter and found that some things don't work.

On the wheel bearings, I used Lucas Red-N-Tacky 2. I cranked the bearings down as much as 65 LB-FT trying to get to the fish-scale readings and I never achieved the correct setting.

I finally went with what I know and now set them to 35 LB-FT.

So, install the shims where they were, check for no play, and go to the next step.
I used the red High temperature grease in the wheel bearings, and then the black grease for the steering knuckle bearings. Torqued to factory specifications. Original shims were both corroded. Mic'd the original shims (.005") and used the same shim from the new kit. Any shims leave the knuckle turning freely. I have a hard time chalking it up to better grease and moving on. Like the original post stated, steering has always felt loose, so leaving the knuckle incorrectly installed seems like giving up. While I can't say I believe even the 15 lbs resistance (if I could get there) would make the vehicle steer noticeably better, I could at least feel like I had eliminated an issue.
 
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Trunnions are factory. They appear to be welded to the axle housing, so it doesn't appear they can be replaced without welding, and who knows what kind of procedure it would require. I am wondering if the trunnion bearing caps can become compressed to the point they are a few thousands shorter than when they were new? I had similar issue once replacing rear wheel bearings where there was a " bearing spacer" in the FSM that eventually a machinist told me was a "crush sleeve" that needed to be replaced. When I went to the dealership to get a new one, it was almost a 1/16" taller than the old one.
Trunions should not be welded. They are removable. After a while they will wear the race and need to be replaced. That's probably why it won't get to speck, you trunnions may most likely be worn out
 
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Trunions should not be welded. They are removable. After a while they will wear the race and need to be replaced. That's probably why it won't get to speck, you trunnions may most likely be worn out
Upper and lower Trunnion bearings, and races were replaced. Not sure what exactly you are referring to as "the trunnion". FSM
Trunions should not be welded. They are removable. After a while they will wear the race and need to be replaced. That's probably why it won't get to speck, you trunnions may most likely be worn out
perhaps we have a misunderstanding of terms. Upper and lower trunnion bearings were replaced including races. The trunnion I assumed you were referring to is the round part of the axle housing.
 
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Let it be known, for the record I have installed a seal backwards. My uncle used to say I could break a steel rod so there's that. It's so odd that with no shims you can't get to the minimal resistance spec on the knuckles. And have leaky seals.
Is your scale reading kilos instead of pounds or any possibilities the scale / tool your using has an issue?
Naw, scale is true (although not recently calibrated). The knuckle turns freely with shims, and without still only has minimal resistance
 

LandLocked93

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Curious, my '93 didn't have shims.
My limited understanding is that only 60 series and older needed shims and that special tool to center the trunion(knuckle?) to the axle.
Orrr I misunderstand the discussion here. Which is very possible.
 
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80s have a shim under the top bearing cap

I assumed in context, by trunnions he was referring to the bearings, but the confusion makes sense
 
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Curious, my '93 didn't have shims.
My limited understanding is that only 60 series and older needed shims and that special tool to center the trunion(knuckle?) to the axle.
Orrr I misunderstand the discussion here. Which is very possible.
Well, my 93 currently doesn’t have shims either, but it had one thin shim ( the kit came with a couple of different thicknesses) on the top. I’m beginning to think I may have damaged the seal when I carefully slip in the axle. The drivers side is about three feet long, so I could see damaging the little spring in it if I let the axle drag on it. The passenger side axle is short and I’m doubtful I damaged the seal on that side. Both sides appear to be leaking.
 
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Toyota's have trunnion bearings. Some vehicles have king pins. When I asked what kind of trunnions you have, I'm asking what brand bearings and part number you installed. That can affect preload. Anyway hope you get it figured out.
I see, I didn’t really notice the brand of bearings. I bought a front axle “kit” from Land Cruiser Parts. they seem to be a pretty knowledgeable bunch of folks. I’m still trying to get a grip on what I may have screwed up. I’m sure you know it isn’t the cleanest task around, so I really only want to tackle it once more. All the time I was carefully cleaning, measuring, and torquing I was telling myself that it should be the last time I have to work on the front of truck for awhile. Guess that was wishful thinking.
 

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