FJ40 Full Floater Axle Build (IH8C-CLIPS)

[LAMBCRUSHER]

AAARG!!! what are you saying, Mace???? that the pig front ax really is 57" WMS??? if so, how could that be if it uses the same guts as the 4X and 7X series? sunnuva loose canon...or are you just messin with me now?

 

[Stumpalama]

So, I am now measuring for inner axle lengths and I get the feeling I am over thinking the issue.
My thought is to use the outer end to limit the inner axle linear travel with a nut and washer retainer at the end and minimizing the spline length to very close to the width of the drive slug.
My question: How much "thrust clearance" should I give between the drive slug and the end washer? I'm thinking around 1/16 of an inch.
My other concern is inner spline length. I figure I should err on the side of making the splines a bit longer given that the inward travel will be limited by the washer.
Lastly, the oil seal surface: the surface on the OEM front inner shafts is 3/4", so I'm thinking I find the center for the oil seal in the rear and extensive out 5/8" on either end to give myself 1 1/4" of total surface as a fudge factor.
Any input from those who have had axles built is appreciated.
Thanks for continuing to play along!

 

[J Mack]

On my axles we used the 40/60/55 Toyota heavy front inner drive shaft snap ring to retain the axles to the drive flange, if you look at my drawings you’ll see the groove for them and the minimal clearance from the root of the splines to the end of the flange to prevent movement. I prefer this to a bolt.

IMHO, I would limit all movement for your “drive slug” and lock it in place with spacers if needed, RCV is going to ask you to measure from your center pin in the ARB to the drive slug and make the axle that length, the issue is you’re going to take those measurements with a tape measure and RCV is not going to factor in any error. I would subtract .250” from your total length on the ARB side and this will allow for any mismeasurement and thermal expansion, if you look into the center of your ARB you’ll see the side gear splines stop about an inch short on the shaft so you’ll be safe with the 1/4” fudge. By locking or limiting movement on your drive slug side you’ll only have axle “float” on the driven side like most every full float rear end.

Make you’re seal surfaces as long as you’re comfortable with, no down side with making them too long.

 

[Mace]

Lol. 55s are the same as a 40

 

[Stumpalama]

Thanks @J Mack . I spent some time with the tape measure tonight and I am confident I got accurate measurements. It's interesting that you said RCV will ask for measurement from the ARB pillow block, since I made sure to measure from the inside edge of the splines to allow for thrust clearance. I also measured the ARB splines to be 1.5" long, so I was going to make my shaft inner splines 1.75"-2" long. I wonder if they will take my exact measurements?

I will give them a shout tomorrow.

 

[Stumpalama]

I butted my FF flanges up to the backing plate flanges on the housing and this netted 1.25” total or .625” per side wider than the factory rear end total width, you’ll need to adjust for your FF flange location. This picture shows what I’m talking about.


View attachment 1233424

Yeah, I realized that the outer are of the axle where you mounted your brackets is exactly 3.5" and Ruffstuff's 3.5" brackets would be perfect if you wanted to match stock axle width.

You're axle specs have the critical numbers i need regarding oil seal surface and spline diameter. Thanks again.

 

[Josie'sLandCruiser]

Hi all,

My experience with FJ55s leads me to believe that the axle assemblies are exactly the same width as 40/45 Series.

One issue that may be "muddying the water" on axle axle widths are where people are measuring from.
Should one measure only striped axle tubes, or fully assembled axles with shafts, brake drums, etc.?

Regards,

Alan

so then rumors of the fj55 front being 57" must be incorrect as well if they take the same inner axles as the 40/70 series...

 

[dr_claw]

Thanks so much for this thread. I have just finished a similar build. I really need to sit down and upload a "build thread" to help with measurements and stuff for people. I took lots of photos and measurements to help.

Key Concepts:

I used a 1978 fj40 axle, and cut off where the dust caps sit. (about 3/4" off either side)
I used ruff stuff weld on flanges that I had to lathe to fit the axle.
The axles I used were an aftermarket poly shaft from a factory full floater 40 series, short side.
I also used a fj80 long side. The short side is about 1/2 shorter that what it should be but seems to work fine.
I bolted everything together and tacked it with diff and axles in, pulled apart and ran short beads about 2" long to prevent warping.
I ran a root pass and then another finishing pass on the outside and inside of the flange.

Great thread + Good luck!

Cheers!

 

[abosely]

Since I had the knuckles, hubs, steering arms, knuckle caps, bearing etc sitting there from the 87' FJ60, I thought what the heck, may as well assemble them on the 87' FJ60 & 74' FJ40 before cutting the knuckles off the 40.

So with everything assembled on the FJ40 and then the FJ60 housing, but without gaskets or shims, but put together and snugged down tight, I carefully measured the WMS to WMS. Was a little surprised as the measurements.

The 74'FJ40 was 56.25" and the 87' FJ60 was 58.5". I checked them several times to be sure since they weren't the 57" & 60" dimensions I was expecting.

Will get the 84' FJ60 rear WMS to WMS measurement in the next day or so and post it up.

Since there seems to be a few different WMS to WMS measurements floating around and this is something that a lot of us want to know, I'm going to start a post and ask for people to post the actual WMS to WMS measurements that they have actually taken and see if we can get some definitive data.

So if anyone has actual WMS to WMS measurements please post them up on the new thread.

Allen

 

[Stumpalama]

Since I had the knuckles, hubs, steering arms, knuckle caps, bearing etc sitting there from the 87' FJ60, I thought what the heck, may as well assemble them on the 87' FJ60 & 74' FJ40 before cutting the knuckles off the 40.

So with everything assembled on the FJ40 and then the FJ60 housing, but without gaskets or shims, but put together and snugged down tight, I carefully measured the WMS to WMS. Was a little surprised as the measurements.

The 74'FJ40 was 56.25" and the 87' FJ60 was 58.5". I checked them several times to be sure since they weren't the 57" & 60" dimensions I was expecting.

Will get the 84' FJ60 rear WMS to WMS measurement in the next day or so and post it up.

Since there seems to be a few different WMS to WMS measurements floating around and this is something that a lot of us want to know, I'm going to start a post and ask for people to post the actual WMS to WMS measurements that they have actually taken and see if we can get some definitive data.

So if anyone has actual WMS to WMS measurements please post them up on the new thread.

Allen

Thanks for the numbers, Allen.
There is already a thread in the FJ40 section that was collecting WMS measurements.

 

[LAMBCRUSHER]

THANKS Allen. I'll quote your post in my thread in the 60 series forum.-(end hijack, thanx Stumpy)

 

[abosely]

What's the title? I'd like to put what ever I find in it.

I missed that thread, I don't want to be adding to extra threads and making it harder to find the inf.

Thanks for the heads up, Stump.
I'm sure enjoying your thread here. Interested in the Studlesd hubs.

Allen

 

[LAMBCRUSHER]

Stock WMS to WMS numbers.....(FAQ) is the thread in the FAQS WHICH HAS INCORRECT INFORMATION and should be updated; Definitely post your findings there. If you wanted to add to my recent thread in the 60s forum, it is here>>> Tech Debate- WMS width of FJ6X front axle thank you for the contribution

 

[Stumpalama]

It's been a little while since I posted an update...
My latest excuse is helping a club member install an H55 in front of his toybox in his FJ62. Good times.

Anyway, I am finally satisfied that I have solid axle shaft measurements and will be sending them to RCV on Monday.
While I wait for the shafts I will finish mounting the spring perches and traction bar, using the original axle as a model for the angles, and building new brake hard lines.

I was toying with the idea of drilling through the perches, since they are so beefy and running the lines through them rather than under or over them. Thoughts?

 

[Cruiserdrew]

It's been a little while since I posted an update...


I was toying with the idea of drilling through the perches, since they are so beefy and running the lines through them rather than under or over them. Thoughts?

I thought about doing this a couple of times but in the end did not because of the PIA factor when they got damaged or needed to be changed. In the end, I've run them above the springs, which also means more disassembly in certain circumstances.

 

[Stumpalama]

Axle order submitted and confirmed via phone with RCV. They are doing up the illustration and will or ward to me for confirmation before sending them to the floor to be cut.
Prices for 4130: $325 long, $275 short.
300m is approximately double the price
I will be burning in the perches and traction bar mount and painting the axle this weekend.

 

[abosely]

You using RCV drive flanges & are you having RCV press fit them to the axles?

Allen

 

[Stumpalama]

No, I am using the TG chromo studless hubs with drive slugs.

Now, the question is since I have the opportunity, should I cut out the drain plug and weld up the hole? Or just run the plug until I wear it down enough then weld it? My last plug and surround was so damaged that the plug came loose from dragging over the rocks. I would prefer to keep the plug, but at the rate I'm going, drain plugs are a throwaway part each time I drain my diff.

 

[jstncse]

I have thought about welding up the drain myself. So far I haven't had a leaker but the ring that protects the drain plug is gone.

 

[abosely]

Duh! Man brain fart! The whole thread is about the studless hubs! Lol

I'm going to form/bend a piece of ¼" plate across the bottom of center from tube to tube (well close) and the width of the center with a hole in it for the drain plug & protection ring and weld between the ring and plate.

Then will have an extra skid plate
and the drain plug & ring will have a smooth surface so rocks don't catch the edge of them.

Allen