Another FJ 40 sterring knuckle preload question

[Highlyinfected77]

My driver's side came apart with 1.2 mm shims on top and 1.0mm on the bottom. Put everything back together as it came out replacing the mangled top shims but measuring the new ones to be the same going in. Got 6lbs on the pull scale. I am running 33x12.5 tires and feel this is a little low so I pulled a .5mm off and replace it with two .2mm. Re torqued everything again and I got 16lbs. Im inclined to leave it as is, just looking for some reassurance.

 

[mattressking]

Here are some questions.

1. New bearings and races or old bearings and races?
2. With or without knuckle seals installed ?
3. Do you have a pack of shims from the 'kit' folks buy?

 

[Highlyinfected77]

Here are some questions.

1. New bearings and races or old bearings and races?
2. With or without knuckle seals installed ?
3. Do you have a pack of shims from the 'kit' folks buy?

New bearing and races. No seals installed yet. I had a pack, now it's half a pack because I put new ones on top. Started with a .5 +.5 +.2 on top and 1.0 on the bottom. Replaced top with same, reused the 1.0 from the bottom because it was flawless. Got 6 lns preload on the arm. Went back and pulled a .5 off on top and replaced with 2 x .2 retorqued and got 16 pounds pre load on the arm. I feel it's high but with 33" talk 12.5" wide tires I think 16lbs is a better number than 6.

 

[WarDamnEagle]

Not sure which year you have but 6 lbs looks like it would have been okay according to this 1977 FSM.

 

[pbgbottle]

Should be removing the same amount of shims from top and bottom to keep the knuckle centered on the axle and housing. Keeps the inner axle seal from premature failure and gear oil leakage.

 

[Highlyinfected77]

Not sure which year you have but 6 lbs looks like it would have been okay according to this 1977 FSM.

View attachment 4086006

I have a 1972

 

[peesalot]

Run it.

 

[Highlyinfected77]

Should be removing the same amount of shims from top and bottom to keep the knuckle centered on the axle and housing. Keeps the inner axle seal from premature failure and gear oil leakage.

That would be perfect is i could find a .05mm shim. I would love to measure and check with the sst, but my spindle bushing look so happy and perfect I'm not willing to risk the trip in and out at this point. I did measure the ball and knuckle with the sst and did the math in inches. Original stack thickness top and bottom total actual was .088" and measured was .083" =.005" =.127 mm difference. .20 being the smallest shim, left me only able to adjust from 1.2mm to 1.1mm on top. Being as the seal was leaking prematurely prior to this i figured i would try this and hunt for a set of spindle bushing this year or machine a sst type insert for the bushing diameter and measure and split next winter if it's leaking by then.

 

[pb4ugo]

Should be removing the same amount of shims from top and bottom to keep the knuckle centered on the axle and housing. Keeps the inner axle seal from premature failure and gear oil leakage.

I would agree with this to a point. I've read many threads where folks said to remove shims equally top and bottom to adjust preload. I've also read some threads to adjust preload by removing or adding a shim thickness to the top stack. If the knuckle is supported by the axle housing(ball) and has no load on the knuckle(floating in the air), then removing shims top and bottom makes sense. But In reality, the knuckle and specifically the lower trunion bearing is supporting the axle housing and vehicle. I think the lower shims/trunion bearing is keeping the knuckle centered to the axle and the upper shims adjusts preload. I'm just throwing this out there.

I recently swapped small pattern disc knuckles to FJ60 large pattern knuckles and centered them with the sst. I did all the measurements and math. In the end i realized. .1mm is equivalent to about 4 thousands of an inch (.004"). I used the Marlin seals and felt confident they could handle a slight misalignment. Most all folks recommend installing the shim stacks in their original orientation as they came off the donor knuckles if you didnt have centering tool. In my experience when I swapped the knuckles and using the sst, I found the final shim stack thicknesses were closer to the shim stacks that were on original small pattern knuckles. The fj60 knuckle shims stacks in their original positions would have had the knuckle way out of alignment. Also there's no telling what the person did that was in there b4 you, so it's always good to center the knuckles.

 

[PidgeonGuggolo]

I'm not 100% sure but I think my knuckles were never redone and are OEM, at least that's what the guy told me. 5 years driving 60k km. So this could be true. They have two shims on top and one at the bottom. Both sides.

Hope this is relevant information.

 

[charliemeyer007]

Its a tractor. Thickness of shims isn't covered by every value, much like bearings or pistons 20 over/under, 50 over/under, so you can easily get 2 on top, one on bottom to get the right spec's.

 

[pbgbottle]

When I swapped knuckles I used the SST. I still had to take it with a grain of salt as I did it multiple times a never got identical results. And when I went to chromo birfs I was surprised to see once I torqued down the knuckle the birf could not be slid out. . When the trunnions where loose I could slip the birf in and out but once torqued down the birf did not come out. So even with correct measurements once tightening it down the knuckle ball actually compressed a bit.
So who knows if it stays centred. I also used the marlin seal been about 8 -10 years. Still no leak. Hmm. Edit. I forgot to mention I installed chromoly bifs so had to grind out inner ball. That’s when I noticed once knuckle installed the birf wouldn’t slide in and out until I loosened the bearing caps.