Minitruck Front Axle Disc Brake Conversion For Dummies (FAQ) (2 Viewers)

[1973Guppie]

pic 1 - finished rotor / hub assembly

pic 2 - assemble the cleaned birfs and inner axles. I did not use the tack method but used the stock clip. I read up on this and many have used several devices in order to hold the clip against the axle in order to slip it in while compressed. 5 minutes with an extra set of hands from the wifey and no prob, they were in. You really need an extra set of hands here. I basically held the clip in with 2 flathead screwdrivers while she pounded on the top of the axle. The whole assembly was in a vice at the time.

pic 3 - clearance the housing to accept the larger mini birfs. I was surprised at how much griding I had to do. I took more off of the bottom than the top. I took the birf and test fit it to see where it was hitting and then marked it with a sharpie. One note here, I found that I only test fit the birf without it being attached to the inner axle, this turned out to be a mistake. After clearancing it, the birf would slip in fine. Later, when I went to put in the whole axle / birf combo I found it did not just slip in. I am guessing this is because the inner axle orients the birf up some so the entry point into the housing is different than if I were doing it with just the birf. So lesson here is to test fit with the birf and axle connected, probably with the seal in place. I was lucky and was able to tap in the birf to get it inside the housing.

 

[1973Guppie]

pic 1 - install seal

pic 2 - pack birfs full of molly grease, use a spatula, much easier to push the grease into the birf

pic 3 - install the wiper stuff, see orientation in pic

 

[1973Guppie]

pic 1 - install bearings, lube first pressing wheel bearing grease into the rolling pins, etc. cover knuckle in grease

pic 2 - install knuckle, coat inside with some moly grease before installing

pic 3 - install top and bottom with shims oriented in proper location / using your labeled marks from before.

 

[1973Guppie]

pic 1 - using the info from the link i posted in the beggining of the thread, test the knuckle bearing preload, mine came out perfect by just swapping shims.

pic 2 - tighten up the backside wiper stuff

pic 3 - slip in birf/axle combo, as mentioned mine took some "persuasion"

 

[1973Guppie]

pic 1 - pack knuckle with grease, spatula helps here

pic 2 - attach spindle, hold with one bolt

pic 3 - then slide on dust cover and new gold seal, tighten bolts

 

[1973Guppie]

pic 1 - pack inside of hub with grease, install greased bearing, tap in new seal, slip hub/rotor assembly onto spindle

pic 2 - install bearing, tab washer and inner nut.

pic 3 - here was the only problem I had. I could not get the proper wheel bearing preload. You are supposed to get this by pulling on a lug nut using a fish scale, I consistently came up with 25 pounds when it should of been 12 at the most. I posted up and others told me to do this process: torque nut down to 45 degress to set bearing and wheel in place. back nut off, spin several times, retorque to 10 pounds, check for looseness, spin couple times, you are done. So, this is what I did.

 

[Isotel]

great writeup!

although i prefer to use way less grease filling the knuckle up! My truck sees not that many miles in 4wd and gets an axle rebuild every 2 years or so.. Its also a pain in the butt when you have to change a birf on the trail with all that grease in there!

 

[1973Guppie]

pic 1 - install star washer and nut, torque down to spec and bend tabs back on washer.

pic 2 - install aisin hub body, you can use a bolt here to pull out the axle a bit, then put on the outer c clip

pic 3 - install outer hub cover and spring, etc and you are done.

 

[Wildman]

Nice wright up, nice clean work too! Damn my jobs always come out (and my shop too) so much more messy

Side note, insted of putting that clip back on that inner shaft next time do the Martack. It makes swaping those crappy stockers out on the trail MUCH easier.

 

[noc231073]

just one question did you use the mini truck steering arms? and if so how did you work out the steering rod issue and did you use the knuckle bearing from a mini truck or the landcruiser?

 

[1973Guppie]

so that's it, final pics. Hope this helps someone out when thinking of doing this conversion!

Noah

 

[1973Guppie]

Nice wright up, nice clean work too! Damn my jobs always come out (and my shop too) so much more messy

Side note, insted of putting that clip back on that inner shaft next time do the Martack. It makes swaping those crappy stockers out on the trail MUCH easier.

yes will probably do the martack on my fj40 next time, this won't be a trail truck though, mainly street/mild off road.

Noah

 

[1973Guppie]

just one question did you use the mini truck steering arms? and if so how did you work out the steering rod issue and did you use the knuckle bearing from a mini truck or the landcruiser?

yes used the minitruck arms, I am planning on using the minitruck tie rod, the drag link will need to be custom depending on what steering box I go with, probably fj60 setup so one end of the drag link will be fj60 and one end minitruck.

bearings I got all from kurt at cruiser outfitters and told him what I am doing and he just sent me it all, actually now to think about it I got all this stuff with the project purchase so not sure, but I did confirm it all with kurt before going forward, he is a good resource.

Noah

 

[numtel]

That's not a minitruck arm on the driver's side...shouldn't it have the j-arm coming off the back. What is that from?

 

[1973Guppie]

That's not a minitruck arm on the driver's side...shouldn't it have the j-arm coming off the back. What is that from?

read in the thread a little closer, I explained how to cut that off

 

[cruiseroutfit]

AWESOME THREAD... I'm going to send ALOT of customers this way... I've been meaning to do a similar writeup for years, but you did a great job

To answer a couple questions that popped up...

Bearings: The knuckle (trunnion) bearings are the EXACT same from the Landcruser & minitruck, so use either though you should absolutely plan on new ones unless you've rebuilt your axle recently.

Steering Solutions: The taper of the mini-truck OR FJ60/62 steering arms is BIGGER than the standard E-84' FJ40/55 tie rod ends. So, you have three options really...

1. Run the FJ60/Minitruck arms (modified minitruck ones as seen in this thread)... AND build a new tie rod with the bigger tie rod ends.

2. Tapered spacers (or the infamous starter bushing). This simply occupies the extra space of the tie rod taper. Its a quick, dirty & cheap fix... but I don't like it for longevity and durability reasons.

3. My personal favorite is using the OEM steering arms from a ~79' - 84' FJ40, they not only have the correct knuckle patter (the big one) but it also has the standard FJ40 tie rod taper dimensions

http://www.cruiseroutfitters.com/steering.html

Related Links:

Landcruiser front axle specs (inner axle lengths, knuckle patterns, etc)
http://www.cruiseroutfitters.com/tech_front_axle.html

 

[1973Guppie]

Thanks Kurt, on your comments on the steering solutions, these are basically for the fj40, correct? On the fj55's, is it common for people to use the minitruck tierod? I measured it against the stock 55 tierod and they are smack dab the same length, plus the minitruck tierod has the input for the drag link. Also, my minitruck tie rod is in way better shape than the cruiser one and thicker. I plan to make or have someone make a drag link. Marlin makes em, so I might give him a call. I plan to go fj60 steering so it should be as easy as one end an fj60 and the other minitruck for the tie rod, correct?

Noah

 

[cruiseroutfit]

It will work on either the FJ40 or the FJ55 as they are identical lengths... however as you mentioned the mini-truck stuff is VERY close. Mini-trucks and FJ40/55 use the same thread on the tie-rod (21mm) while the FJ60 & FJ80 are quite a bit bigger (23mm), likewise the draglink on the FJ40 is 17mm & 21 mm on the FJ60/80. So you won't be able to use a mini-truck end and an FJ60 end on the same tube (unless it is custom made with different threads at each side). I'm not sure if all of the mini-truck stuff uses the 21mm tie rod & 17mm draglink stuff, and what years if so... but the LC stuff I should have nailed down by now?

 

[handcannon]

1973 Guppie

Thank You! Thank You! Thank You! I've got almost this same project ahead of me, except that it is an axle out of a 1978 FJ55 that I need to rebuild knuckles on. All those pics are pure gold!

 

[1973Guppie]

Kurt, yes I will probably just get something custom made or just use some threaded inserts on tube and weld it up.

Handcannon, no problem, let me know if I can help at all when you start building.

Noah