Build The Truck of Theseus
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littlevulture
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- #182
If you're already out in the shop and it's convenient, otherwise don't worry about it. I found some great pictures in Lucilles build this morning.
I already have clearance on the housing since I'm flipping it to driver drop to work with my transfer case. Guess I'll throw it in there and see if its even worth continuing to explore a HP front.
I'm currently thinking I'll just stick with the low pinion up front. If I put my low pinion in and roughly point the pinion towards my case output (planning on a double cardan front shaft) everything seems to tuck perfectly into place at full compression. I've gotta french my spring perch into the axle on the diff side so I only get 1 or 2 chances to set the pinion angle properly before the axle housing starts getting mangled.
littlevulture
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- #183
Getting back to the truck finally, haven't touched it at all since the last post. I found another VF4 transfer case while I was visiting family back in November, I brought it home after Christmas. Notably this one is from a 2005-2007 Sequoia which is important because they used a VSS in the transfer case for a speed signal instead of pulling it from the ABS system like the 4th gen 4Runners do (which is where I got my VF4 that I modified). I noticed that the VSS and cable drive adapter for the cable driven speedometers looked awfully similar so I took a gamble and bought it. The only part I needed was the housing extension for the drive flange seal but the case was cheap. The VF4 has a larger rear bearing than the VF1/2/3 and the 2005-2007 Sequoia seems to be the only vehicle that has the larger bearing in the rear of the case and a mounting location for a speed sensor. Left is the VF4 case extension, VF1 is on the right, the VF4 bearing is almost 0.5" bigger in diameter.
Top is the speedometer drive gear assembly from my original 1988 VF1, bottom is the vehicle speed sensor from the Sequoia.
Unfortunately the gears are slightly different sizes so both the VF1 worm gear and plastic bevel gear will have to go onto the VF4, this is a problem because there isn't any easy way to drive the older style gear on the newer case. Left is the original VF1 speedo gear, right is the newer VF4 speedo gear which is about 3mm smaller in diameter.
The VF1 drives the speedometer worm gear with a small ball bearing that sits in a hole in the output shaft and interfaces with that notch on the worm gear. Unfortunately the VF4 output shaft is doesn't have this hole and it's hardened so I can't add one.
The newer VF4 is splined onto the output shaft using the same splines that the driveshaft flange uses, note the splines on the front of the newer worm gear.
Overall this is gonna work great and keep my original speedometer working with that VF4 I modified earlier this year. The only problem is figuring out how to ensure the worm gear is driven by the output shaft. I might try and make a splined adapter to press into the old worm gear to adapt it to the newer drive style. I'm also thinking of just letting friction drive it. When the output flange is installed the worm gear acts as a spacer and seems to be locked in place by the compression from the drive flange nut. I assembled it without the rear cover to see what was actually going on inside I couldn't get a 0.001" feeler gauge in there and the flange nut was only snugged. My gut tells me this will be plenty to keep that worm gear from slipping on the shaft but it does make me wonder why Toyota felt it was necessary to include a mechanism that ensured it was mechanically locked to the shaft.
Top is the speedometer drive gear assembly from my original 1988 VF1, bottom is the vehicle speed sensor from the Sequoia.
Unfortunately the gears are slightly different sizes so both the VF1 worm gear and plastic bevel gear will have to go onto the VF4, this is a problem because there isn't any easy way to drive the older style gear on the newer case. Left is the original VF1 speedo gear, right is the newer VF4 speedo gear which is about 3mm smaller in diameter.
The VF1 drives the speedometer worm gear with a small ball bearing that sits in a hole in the output shaft and interfaces with that notch on the worm gear. Unfortunately the VF4 output shaft is doesn't have this hole and it's hardened so I can't add one.
The newer VF4 is splined onto the output shaft using the same splines that the driveshaft flange uses, note the splines on the front of the newer worm gear.
Overall this is gonna work great and keep my original speedometer working with that VF4 I modified earlier this year. The only problem is figuring out how to ensure the worm gear is driven by the output shaft. I might try and make a splined adapter to press into the old worm gear to adapt it to the newer drive style. I'm also thinking of just letting friction drive it. When the output flange is installed the worm gear acts as a spacer and seems to be locked in place by the compression from the drive flange nut. I assembled it without the rear cover to see what was actually going on inside I couldn't get a 0.001" feeler gauge in there and the flange nut was only snugged. My gut tells me this will be plenty to keep that worm gear from slipping on the shaft but it does make me wonder why Toyota felt it was necessary to include a mechanism that ensured it was mechanically locked to the shaft.
Do you think a small diamond hole saw bit or similar Dremel tool bit could grind out a hole for the ball? Or would that weaken it? A set screw in the gear? Retaining compound? I'm sure you'll find a way.
Is it possible to 3D print a new Speedo worm gear or is it possible to swap the shaft that the speedometer gear is pressed on to and swap them between the two housings?
littlevulture
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- #186
I ruled out retaining compound because it would make disassembly a pain in the future even though it's the simplest option. Dremel is an interesting idea, I doubt it would weaken it in any meaningful way. I'm thinking a pair of set screws would probably be the easiest but they'd probably need to be a tiny M3 grub screws to fit in that little part of the worm gear without teeth so I'm not sure how tight I could actually get them. I have another stupid idea that uses some new lathe tooling I happened to order a couple days ago that I think I'll try first whenever the tools show up.
littlevulture
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- #187
I thought about that but I can't really find any good models of the gears online and I'm not good enough with the free CAD software I use to make a good gear. I also don't want to change the gear ratio in there, the factory 11/32 ratio speedo ratio is perfect with 35's and 4.88's, if could swap the gears I'd have a 11/30 in there and that'd be off by about 7%. I don't think I can swap them anyways because they seem to be molded directly onto the shafts and the shafts aren't interchangeable.
littlevulture
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- #188
Finally committed and notched my axle housing for the spring perches yesterday. I found this trick on Youtube awhile back that uses a laser level to project a plane onto an irregular surface, in this case I needed to project a plane that touched the bottom of the tube part onto the less tubular diff mounting area. Started with the laser and made sure the axle was parallel with the level line.
Then I set the pinion angle with a digital angle finder, killed the lights, and set the height of the laser level to just intersect the bottom of the axle tube (a floor jack was great for adjusting the height). It's hard to tell exactly what is going on here but the upper horizontal laser line is just touching the bottom of the housing while still projecting beneath it to the far wall. I traced that line with a sharpie then flipped the axle and did the same for the other side.
The resulting notch that needs to be removed and the housing after it was cut out
Finally double checking that spring perches are sitting in the same plane and that the axle is parallel with that plane. The right side (passenger) just rests on the bottom of the housing which was the reference plane. Laser level was super useful and I wish I had bought one sooner.
Then I set the pinion angle with a digital angle finder, killed the lights, and set the height of the laser level to just intersect the bottom of the axle tube (a floor jack was great for adjusting the height). It's hard to tell exactly what is going on here but the upper horizontal laser line is just touching the bottom of the housing while still projecting beneath it to the far wall. I traced that line with a sharpie then flipped the axle and did the same for the other side.
The resulting notch that needs to be removed and the housing after it was cut out
Finally double checking that spring perches are sitting in the same plane and that the axle is parallel with that plane. The right side (passenger) just rests on the bottom of the housing which was the reference plane. Laser level was super useful and I wish I had bought one sooner.
littlevulture
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- #189
I'm still pretty convinced this was unnecessary but I added a splined insert to the speedo drive gear, basically an excuse to play with the new boring bar I bought. Splines are made from a cut down transfer case output flange. Surprisingly the splines were the only hardened thing on the flange and they were barely hardened past the surface so cutting it wasn't any problem. The splined adapter is pressed into the recess I added in the worm gear and I also put some blue locktite in there. Only used blue because I wanted to put M3 grub screws in the face (parallel to the splines) but after some measuring I realized that wasn't gonna work. If this ever starts to spin I'll reassemble with red or some real retaining compound.
Pretty slick. 
Which laser level did you pick up? Pretty slick to use it on the axle.
littlevulture
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- #192
I got this Klein one from Lowes, it was the cheapest green laser with both horizontal and vertical that was rated to 50 feet. I went with green because it's apparently easier to see in bright light. The emitter on this one auto levels on what I'm assuming is a weighted gimbal system, not as fancy or as accurate as the more expensive models but it's working great so far.
littlevulture
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- #193
Bit of a depressing evening, did my first mockup of the steering and found that the tie rod seems to hit the diff cover prematurely. I don't have a good way to measure the steering angle right now but looking at my other junk housing with the factory steering stops and some spare knuckles I'd guess I'm missing out on about 15% of the steering range here based on the knuckle alone. I'm reading online that the wiper/seal on the knuckle limits steering to a maximum of about 45 degrees which is less than the bare knuckle, anyone here actually know how many degrees a fully assembled knuckle can turn? I'll have to try and come up with a good way to measure the steering angle.
Root cause is copying the locations for the rod ends from a high steer setup which obviously will clear the diff...turns out redesigning everything without considering absolutely everything will cause problems. Good news is the vertical position is just about perfect and shouldn't be the limiting factor on upwards axle movement.
Not sure what to do about this, I really don't want to commit another week to making a new pair of steering arms right now. I know the Jeep JK/JL and some other OEM setups use offset rod ends to solve this exact problem but I don't see those are available in the FJ80 style.
Tie rod clearance to frame and engine at maxish compression looks really good so far.
Root cause is copying the locations for the rod ends from a high steer setup which obviously will clear the diff...turns out redesigning everything without considering absolutely everything will cause problems. Good news is the vertical position is just about perfect and shouldn't be the limiting factor on upwards axle movement.
Not sure what to do about this, I really don't want to commit another week to making a new pair of steering arms right now. I know the Jeep JK/JL and some other OEM setups use offset rod ends to solve this exact problem but I don't see those are available in the FJ80 style.
Tie rod clearance to frame and engine at maxish compression looks really good so far.
Too much contact to clearance the cover? I didn't know the JK's had offset TRE's. Unless you're talking about the offset Heim joints. They also work. I think Ruff Stuff and Barne's sell offset Heims. Maybe others too.
littlevulture
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- #197
It's hard to get a measurement but the cover doesn't seem to clear the diff by much so I probably can't get much from clearancing it. And yeah they're funny looking rod ends, I can't imagine why this is the solution when you're designing a blank slate vehicle with all the engineering resources of an OEM. This is an upgrade kit but the OEM ones are the same shape.
Thanks for pointing out the obvious solution, that completely slipped my mind as an option. I threw a hub and wheel on to check some other stuff and the tire seems to hit the leaf pack right about when the tie rod hits the diff cover so it might work without changing anything if I set the steering stops based on the tire/spring interference.
IDK how much steering angle the knuckles and Birfs are capable of. 
I set my steering stops at the point the steering box stopped moving. That's with Trail Gear steering arms and early IFS steering box. I had to make a spacer for my hydro assist cylinder to limit travel to match my steering stops and box limit.
I'm looking forward to your solution.
I set my steering stops at the point the steering box stopped moving. That's with Trail Gear steering arms and early IFS steering box. I had to make a spacer for my hydro assist cylinder to limit travel to match my steering stops and box limit.I'm looking forward to your solution.
littlevulture
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- #199
I'm almost certain I'll be losing some potential steering angle compared to the max because the OEM FJ Cruiser wheels I have are -15mm offset (I think). I'm pretty sure most aftermarket wheels have more negative offset than mine but I didn't have any complaints about turn radius before so hopefully I'll still be happy with this setup. I'll try to remember to get some angle measurements when I do a more complete assembly later, I've also got an early IFS box and my arms are based on what I think are TG arms so maybe the box will max out before anything else?..so many variables to play with and I'm such a slow fabricator.
littlevulture
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- #200
Can anyone point me towards some good resources on shackle inversion? I've been seeing it pop up in the 60 forums where people use anti-inversion shackles to prevent the problem but I can't find any good info on why it happens. So far I've only been able to find this one single picture of an inverted shackle even though there's lots of discussion on the topic (mostly around anti-inversion shackles to prevent it).
I placed my front hanger with the main leaf fully drooped using the weight of my completely bare housing. The result was a perfectly vertical shackle at full droop which is what I was aiming for. At full compression where the spring is nearly flat the shackle is perfectly horizontal.
Full droop (unweighted).
Full compression.
When I added the knuckle ball, knuckle, steering parts, and a wheel/tire the extra weight pulled the leafs down past the natural free arch position and caused a negative shackle angle at full droop, although the little clamps on the spring pack should limit that some when I remake them. After messing around tonight I'm pretty sure the only way a shackle can invert is if it goes so negative it ends up co-linear with the spring at full droop, which under the right circumstances could allow it to go over center (the wrong way) when the wheel starts to move back up. At full droop on the passengers side I've currently got about 30º between the shackle and the spring with the weight of everything aside from the brakes and axle shafts and slightly less than that on the drivers side because the diff is over there.
I can get my shackle back to vertical under the weighted condition if I slide the front hangers back about 15mm and increase the shackle length by that same amount. Any of you that have some actual experience have thoughts on the inversion problem? I'm pretty sure it'll be a non-issue in the current position, especially when the little clamps are back in place and the spring pack behaves more as a complete unit.
Also these are the little clamps, is there a better name for them?
I placed my front hanger with the main leaf fully drooped using the weight of my completely bare housing. The result was a perfectly vertical shackle at full droop which is what I was aiming for. At full compression where the spring is nearly flat the shackle is perfectly horizontal.
Full droop (unweighted).
Full compression.
When I added the knuckle ball, knuckle, steering parts, and a wheel/tire the extra weight pulled the leafs down past the natural free arch position and caused a negative shackle angle at full droop, although the little clamps on the spring pack should limit that some when I remake them. After messing around tonight I'm pretty sure the only way a shackle can invert is if it goes so negative it ends up co-linear with the spring at full droop, which under the right circumstances could allow it to go over center (the wrong way) when the wheel starts to move back up. At full droop on the passengers side I've currently got about 30º between the shackle and the spring with the weight of everything aside from the brakes and axle shafts and slightly less than that on the drivers side because the diff is over there.
I can get my shackle back to vertical under the weighted condition if I slide the front hangers back about 15mm and increase the shackle length by that same amount. Any of you that have some actual experience have thoughts on the inversion problem? I'm pretty sure it'll be a non-issue in the current position, especially when the little clamps are back in place and the spring pack behaves more as a complete unit.
Also these are the little clamps, is there a better name for them?