Setting Knuckle Preload Issue (1 Viewer)

[MK80]

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]

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]

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]

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

 

[MK80]

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

I don’t see anything listed under 80 series. What am I looking for?

 

[ajax1]

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

 

[tmxmotorsports]

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?

 

[Swifty80]

I’m currently in process of a full front driveline overhaul, all new parts , also bought myself the superior knuckle pull scale. Replaced the shims with new equivalent to what was in previously and after measuring and then re-shimming hunting for the 6-10lb force , I’m running no shims and just managing 6lb of force . So my question is it fine to run in shim-less or is something not right. Thanks

 

[mudgudgeon]

I’m currently in process of a full front driveline overhaul, all new parts , also bought myself the superior knuckle pull scale. Replaced the shims with new equivalent to what was in previously and after measuring and then re-shimming hunting for the 6-10lb force , I’m running no shims and just managing 6lb of force . So my question is it fine to run in shim-less or is something not right. Thanks

I agree with @BILT4ME post right at the top. Reinstall the same as it came apart, button it up, and call it good.

Take your fish scale fishing and lose it in the creek.

 

[sunrk]

If the pre-load is too low reduce the shim stack - if too high increase it. Toyota makes (or made) them in several different thicknesses. It never hurts when rebuilding swivel hubs to use the same shim stack that was already with each top kingpin and just check it as it's easy to correct. If it can't be corrected to be in the right range, something else might be wrong (like a bearing race not seated properly).

If you need to have no shims to get the correct pre-load, that's perfectly ok. The shim stack provides for fine adjustment.

 

[MUDZLLA]

I think I've only seen one shim on the top, none on the bottom, in 3 different trucks. All seemed identical on both sides but never thought to just throw them all together and let god sort em out. Worrying about rotational preload on bearings just goes against common sense somehow.

 

[sunrk]

The bottom is *never* shimmed - only the top kingpin. The bottom steering arms are secured with studs, cone washers, spring washers and nuts and you can't use shims there.

 

[Rusty Marlin]

It's a little late now, but in the future, don't pull the top cap. It's not necessary. Pop the TRE's, remove the lower trunnion and then lift and tilt the knuckle off the housing. Pull the bearing off the upper trunnion with a pair of screw drivers wiggled gently. The new bearing will slide right over the shaft, might need to wiggle it a little to get it aligned, but shouldn't need to force it.

When reassembling the knuckle, you set the top bearing in the cup, then rotate the knuckle back down with the lower bearing slipped in between the knuckle and housing. Then use the four lower knuckle studs draw the steering arm back onto the bearing evenly.

Easy Peasy, No shims to futz around with.

About 15 minutes in to see disassembly,
About 29 minutes in for reassembly.

 

[Swifty80]

Yeh with the shims it came with it

It's a little late now, but in the future, don't pull the top cap. It's not necessary. Pop the TRE's, remove the lower trunnion and then lift and tilt the knuckle off the housing. Pull the bearing off the upper trunnion with a pair of screw drivers wiggled gently. The new bearing will slide right over the shaft, might need to wiggle it a little to get it aligned, but shouldn't need to force it.

When reassembling the knuckle, you set the top bearing in the cup, then rotate the knuckle back down with the lower bearing slipped in between the knuckle and housing. Then use the four lower knuckle studs draw the steering arm back onto the bearing evenly.

Easy Peasy, No shims to futz around with.

About 15 minutes in to see disassembly,
About 29 minutes in for reassembly.

Hey all thanks for the replies, yeh I understand what you saying if you don’t disturb the top cap/shims etc just splap it together and it’ll be fine, but even then the knuckle pre-load could still be out, and if you going as per Toyota specs 6-10lb you will need to shim it. Anyway mines close enough without shims, I’m wondering if a thicker type of grease packed hard into bearings could’ve altered the reading.
Cheers

 

[mudgudgeon]

Yeh with the shims it came with it


Hey all thanks for the replies, yeh I understand what you saying if you don’t disturb the top cap/shims etc just splap it together and it’ll be fine, but even then the knuckle pre-load could still be out, and if you going as per Toyota specs 6-10lb you will need to shim it. Anyway mines close enough without shims, I’m wondering if a thicker type of grease packed hard into bearings could’ve altered the reading.
Cheers

The fish scale method is primitive IMO.

Differences in grease consistency has been proven to make the scale readings meaningless