Steering knuckle centering tool instructions (FAQ)

[Tokamak]

Slickdog,
Here is info on my home built centering tool.

https://forum.ih8mud.com/40-55-series-tech/569834-home-built-knuckle-centering-tool.html

 

[Tokamak]

Here are the dimensions of the one I built. Dimensions may not be the same a factory but it works.

 

[Slickdog]

Thanks Tokamak


This needs to be in this FAQ! However when I save the drawing and expand it the detail is lost. can you post as a pdf?

 

[Tokamak]

Here is a PDF. Won't let me attach a 3d model step file.

 

[Slickdog]

Thanks again Tokamak however all your dimensions are in Imperial and Toyota were built using the metric system.
I have tried to convert your dimensions and they don’t match exactly.
Bearing /Swivel cap dimension 0.81” = 20.599 (20.6) mm I would have thought Toyota would have made this 20mm or 20.5mm.
Bearing Spigot you have as 0.668” = 16.967 (16.97) mm I would have thought this would have been 17mm – a press fit no interference.
I will therefore make my bearing/swivel cap substitutes 21mm and my shaft at 17mm with 16mm ends.
I’ll make my tool from your Basic dimensions, converting to metric, but will copy the basic layout of the Toyota tool, i.e. a single shaft running through the bearing/swivel cap Substitutes.
With My tool each time I use I will compare the end cap dimensions and add/ subtract the difference when carrying out the measurements, due to not having the exact dimensions with me.
I noticed your thread about the deflections in the hub and swivel you can obviously check this with a dial gauge while tightening the tool. I believe the deflection to be minimal and of little consequence.
Once again thanks for the input I certainly could not make my tool without your help.

 

[Tokamak]

No problem slickdog,

I did not have a pattern or factory dimensions when building mine. The dimensions are based on measurements I made using calipers on my knuckles. Built to fit.

 

[PabloCruise]

Pic 4: Mount the spindle to the knuckle housing. Torque all bolts to spec 11-16 ft lb. (Make sure to get the right spindle mated to the correct knuckle. )

Pic 5: Install the rod assembly minus the spring arm and tighten the nuts just enough to allow the rod to be turned. Pull the scribe forward and again rotate the rod to scribe the second line.

Pic 6: Remove the rod assembly. Do not disturb the scribed lines. Secure the rod in a vice or something else and carefully measure the distance between the two scribed lines. This is where you can get off a bit. Measure it twice then let your buddy measure it. Write this down as measurement D.

Now to get the TOTAL shim thickness (both top and bottom shims added together)

Total shim thickness (Call it C) C = A - B Write this down.

To get the BOTTOM shim thickness

Bottom Shim (Call it E) E = D - 3mm

To get the top shim thickness

Top Shim (Call it F) F = C - E

Totally confusing I know. Just read the instructions a few times.

Coolerman - thank you.
I am going to need to do this soon...

 

[The Punter]

Here's the missing pic, hope it helps

 

[cuencanolenny]

I think anything would work better than grease, removing the lower bearing wiped almost all of the mark off using yellow grease.
If I had to do it again I'd use machinist blue dye, I think it's then same thing Poser is talking about.

You are thinking of Dykem. It is like a luminescent blue lacquer. Prussian blue is more like a grease. You use Dykem when you are laying out something that you will say scribe onto the metal leaving a shiny line in the blue background. Prussian blue is used when you want to find a high spot. When "mating" a male and female hammer or stretch form die set you would smear Prussian blue on one mating surface and then put them together/lower the press ram. Then when separated the high spots will be revealed. So in this application Dykem (red or blue dye) would be better as you will get a crisper line.

 

[rusty_tlc]

You are thinking of Dykem. ....... in this application Dykem (red or blue dye) would be better as you will get a crisper line.

Exactly, I couldn't remember the name when I posted back in........ 2009!

 

[crash80]

So I'm in the process of changing out my '78 knuckles to the bigger stud later model knuckles.

I built my own centering tool and at first I didn’t think the equations added up but I pulled my head out of my a$$ and found my problem.

 

[iptman]

The second video in this thread is all about how to use the centering tool. See if your method matches up. If it does, you're probably good to go.

Knuckle Rebuild Video Series

 

[Trialsallday]

I got my hands on the tool today, but one thing I realized is I don’t remember which spindle went to which knuckle..
I had everything cleaned not thinking I needed to know ..how bad is that ?

 

[60Works]

Hello all,

I recently purchased a replica alignment tool from a reliable vendor and am having trouble getting measurements which make sense. I'd like to confirm either that its off or discover that I'm doing something wrong before approaching the vendor.

The two bearing hats seem to be off but I've never used an OEM tool to compare. The depth of the hat is shorter than the actual bearing caps and the hat step varies significantly from the measuring flat. Could someone please provide the 3 step dimensions for the hat on an OEM tool?

Thanks in advance.

 

[iptman]

I don't think the lip or the overall measurements matter since you should be measuring inside the lip. Here's our club's oem tool measurements inside the lip. Only .001 difference.

 

[FJ406]

Warning if you don't want to get fussy, walk on by and have a nice day... So I'm going to do my knuckles because my axle seals seem to be fried...3k miles after the PO had knuckle work done according to service records--not sure to what extent = red flag. Without the red flag, I would be OK with doing the knuckle rebuild with existing shims going back where they came from. Red flag leads me to want to at least 'verify in the field' the existing shims; so I buy an aftermarket knuckle centering tool. I'm not cheap by nature but, $200... Per @Juggernaught I check the specs on the tool. Correct me if I'm wrong but the only critical dimension of the oem tool is the one above in @iptman post. On his tool, the measurement to the 'shoulder' .8065 looks to be =/same as to the bottom of the upper lip. In measuring my tool, the measurements of shoulder to shoulder are different from bottom of lip to bottom of lip.

The difference is noticeable in the milling as seen here, and in the last pic from @Juggernaught post above:

This leads me to think that with this specific aftermarket tool, it would be more accurate to measure from the bottom of the lip instead of the top of the shoulder to get measurement "A" from FSM. I, and possibly others, would appreciate if people with the OEM SST would measure these two dimensions, to verify a standard (not to question iptman, cause that's the standard till I hear otherwise). I would like to establish a bench mark for the critical dimensions so that various aftermarket and home made tools could be 'calibrated'. If my tool is off, it doen't matter so much, if I know how far off it is and can take that into account. I would also pass along to the vendor so they could maybe correct their specs. I found a lot of consternation with the centering tool in past threads, and I wonder if some of that isn't due to milling variations and/or aftermarket variations.

My apologies to @Coolerman for hijacking his great thread. My endeavor here is to establish the extra verification/math to ensure an accurate outcome for those who want the use the SST or an aftermarket variation for a knuckle rebuild-- a calibration of tools if you will. Cheers, matt

 

[OTRAMM]

 

[FJ406]

The 'shoulder to shoulder' measurement in the pic above seems the critical measuring component of the SST. @iptman specs: 1.614in or 40.99mm and @OTRAMM specs: 1.612in or 40.94mm suggests to me that OEM is basically 1.613in or 40.97mm (or so). Since my 'shoulder to shoulder' distance is 1.549in or 39.34mm, when I take my knuckle measurements I should probably add .064in or 1.63mm to the "A" distance in the shim equation to get proper results. Not surprising some folks might be getting odd shim numbers with an aftermarket tool, given that mine is out by the thickness of several shims? FWIW, I'm still planning on keeping track of the existing shims, and hopefully verifying that they are indeed correct. Or maybe I'm missing something? Time will tell...Thanks guys for OEM specs and pics. cheers, matt



EDIT 5/18/18: The Aftermarket tool supplier, having become aware of the situation, has sent out replacement shoulder bushings at no cost to those of us who purchased them. Mine came unsolicited, and they look great and are spot on relative to OEM SST specs. I left my previous posts intact because others have responded to them. In my case the aftermarket knuckle SST issues have been resolved and I am very satisfied with both the tool and the vendor. Once again, MUD members provide great expertise, products, and integrity. Cheers

 

[FJ406]

I made a shim calculator worksheet if anyone is interested. Checked it with @OTRAMM numbers from his video--thanks Ryan! Here is a PDF of the worksheet as an example. As a spreadsheet the (blue) measured values can be changed to calculate shim measurements. I'm not able to upload the spreadsheet file so if you want me to send it to your e-mail, PM me. Cheers, matt

 

[60Works]

Thank you all for your contributions. I do apologize for hijacking Coolerman's thread but I feel that providing actual measurements of this tool is a benefit to the purpose of the thread. My desire was to consolidate data on this definitive thread for future searchers. (BTW - the 'reliable vendor', being reliable and awesome, agreed that the step was off and immediately offered me a replacement tool.)

The FJ-60 knuckle is 6.50" flat to flat so you need a caliper larger than the typical 6".

The pointed scriber which sits inside the axle and spindle will work with in a spindle with the bushing removed. An unbushed spindle has the same dimension as the axle seal.

EDIT - I would like to partially retract the 2 italicized paragraphs below. Now that I fully understand the tool and process, I can see why the height of the brim does not matter and where the 3mm in the formula comes from. There are 2 critical dimensions:

1) The 'shoulder to shoulder' as previously stated.

2) The diameter of the bolt.

The 3mm is a correction in the formula to account for the scribe not being able to reach the center of rotation of the trunion. If the bolt could be replaced by a thread, the 3mm would not be necessary. It is the tangent of the angle of the trunion off vertical times half the diameter of the bolt. I'm a bit embarrassed not to have figured it out immediately.

3 mm = tan(trunion angle) * .5(bolt diameter)

Knuckle Alignment Tool - Why 3mm?

I disagree with previous posts stating that the only critical dimension is the 'shoulder to shoulder'. The shoulder dimensions should match the bearing caps. Their sole purpose is to replicate the caps with the bolt installed. The shoulders measure total shim thickness but they cannot on their own supply top and bottom allocation of shims. This is provided by the scribed lines on the bolt.

The brim of the hat comes into play when the tool is moved to the knuckle with the spindle attached and the second line is scribed on the bolt. E = D - 3mm. Logic says that the 3mm should be the brim dimension. The brim on my tool measures .204" or 5.18mm. This random measurement, neither SAE or Metric, doesn't fit any logic and Toyota usually has a reason for everything they do.

Could someone please provide the brim dimension on an OEM tool? Thank you, all.