Setting Knuckle Preload Issue

MK80

MK80

Joined
May 4, 2021
Messages
42
Location
AF, Utah
I am finishing rebuilding my knuckles and I'm running into a problem. When I disassembled my knuckle originally I don’t remember how many shims there were underneath the top cap and two bolts. But now with only the thinnest of shims I cannot get the preload to go over 4# before my spring gauge starts pulling the steering arm.

I made sure my trunnion races are seated all the way down and verified my torque setting with another torque wrench.

What can I do to get to the 5.6# of starting preload?
 
BILT4ME

BILT4ME

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Nov 9, 2012
Messages
11,783
Location
Olathe, KS, USA
I am finishing rebuilding my knuckles and I'm running into a problem. When I disassembled my knuckle originally I don’t remember how many shims there were underneath the top cap and two bolts. But now with only the thinnest of shims I cannot get the preload to go over 4# before my spring gauge starts pulling the steering arm.

I made sure my trunnion races are seated all the way down and verified my torque setting with another torque wrench.

What can I do to get to the 5.6# of starting preload?
What year?

Typically, the trunnions are set with shims ONLY on the top cap. You're supposed to place them back in, regardless of new bearings or not.

Depending on what brand / type of lubricant you are using, it can affect the preload numbers. The current lubricants are MUCH better than what they were when your truck was built.
I used Lucas Red-N-Tacky 2 on mine and I intentionally torqued mine well beyond what it's supposed to be to see how it affected preload. I was unable to achieve the preload numbers, despite way over-torquing the nuts.

Place the shims, tighten the bolts to the FSM advised torque, and move on. Seriously.
 
MK80

MK80

Joined
May 4, 2021
Messages
42
Location
AF, Utah
What year?

Typically, the trunnions are set with shims ONLY on the top cap. You're supposed to place them back in, regardless of new bearings or not.

Depending on what brand / type of lubricant you are using, it can affect the preload numbers. The current lubricants are MUCH better than what they were when your truck was built.
I used Lucas Red-N-Tacky 2 on mine and I intentionally torqued mine well beyond what it's supposed to be to see how it affected preload. I was unable to achieve the preload numbers, despite way over-torquing the nuts.

Place the shims, tighten the bolts to the FSM advised torque, and move on. Seriously.
It’s a ‘97. I’m using MasterPro Hi Temp Red Lithium NLGI 2 wheel bearing grease on the trunnion bearings.

Sounds good, I’ll torque it and not worry about it. Thanks.
 
tmxmotorsports

tmxmotorsports

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@TRAIL TAILOR has the tools on hid site to figure out how get the correct shims
 
ajax1

ajax1

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Feb 7, 2009
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2,637
This is a sst by Toyota I only used this on 40s, 55s,60s never needed on the 80 you reuse the shims that are there and on the top
The tool is used to set centering of the knuckle
 
Last edited:
tmxmotorsports

tmxmotorsports

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This is a sst by Toyota I only used this on 40s, 55s,60s never needed on the 80 you reuse the shims that are there and on the top
The tool is used to set centering of the knuckle
Yep thats what its for. So what happens if someone else hase been into the front axle not knowing what there doing and mixed some shims up...you just put what they had back in there and call it good?
 

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