Diamond Axle - 9.5" Center - Full Float - "Extra Wide" - Rear Axle Upgrade

[sbechtold]

After finishing my SAC project I wheeled my FJC for a few months, jumped right into my next project. I wanted to increase the rear axle width by 3.5" and move up to a larger third that would handle the weight (5200#) of the FJC. I decided to go with a full float axle running a Land Cruiser 9.5" third with an ARB. I then called Brian Ellinger at Diamond Axle and placed an order for a new rear axle. Brian was great to work with and makes incredibly strong axles (I have one of his axles under the front already ). I then called Jim at Inchworm Gear and ordered the Land Cruiser 9.5" third member.

Here are the rear axle specs:

• Diamond Axle housing
• FROR Full Float ends
• 67.75" WMS-to-WMS
• FJ80 LC 9.5" third member
• 4.88 gears
• ARB air locker
• Solid pinion spacer
• Quad drilled flange
• Toyota IFS Hubs
• Longfield drive flanges
• Custom length 30 spline chromoly axle shafts
• Reused my FJ Cruiser stock brake setup (rotors, calipers and emergency brake setup )

I am re-using my FJ Cruiser backing plates, emergency brake setup, calipers and rotors. Brian was able to design and build an adapter that allowed the FJ Cruiser stock brake system to bolt right up to the housing.

Before jumping into the pics here is a quick comparison of the Toyota 8" third to the Land Cruiser 9.5" third.

9.5" on the left:



9.5" on the right. That ring gear is huge compared to the 8".



Before I started to disassemble the rear axle I needed some jack stands. After shopping around I decided to make my own. A little 3x3x3/16th square tube and this is what I came up with. The stands are adjustable in 3" increments.



FJC up on the jack stands. Let the rear axle removal begin.



Axle out and ready to be disassembled. I sent the stock axle housing, axle shafts, backing plates, calipers, rotors and ebrake setup to Brian so that he could use them to make the new adapter that allow me to reuse all the stock braking parts.



Toyota uses the same semi-float design on the FJC as they did on earlier models.



Empty axle housing...



I shipped all the parts off to Diamond and Brian works his magic.

[sbechtold]

Fast-forward in time a little; Brown brings me a couple of boxes that contain some sexy parts.









Brian emailed me this comparison shot of my stock housing and the new 9.5" housing before he shipped the axle to me.



After replacing all the leaf spring bushings I bolted the leaf springs back into place. Installed some ARP studs for the third member, then installed the inner oil seals and installed the third.





I then rolled the axle under the FJC and bolted it in place.



Here the axle is mounted and the u-bolts and shocks installed.

[sbechtold]

First step to assembling the rear axle outters was to do a dry fit of all the parts. I have to say that for completely custom parts Brian at Diamond did an unbelieveable job. The tolerances are super tight and everything bolted right up.

Here are all the parts required for one side ready for a dry fit.



Here the spindle and brake adapter are installed.



Emergency brake setup installed.





Here the caliper is bolted up along with the wheel hub.



And finally, completed dry fit with all parts installed. Everything fits very nice! Pretty amazing that Brian was able to combine my FJC backing plates, emergency brake setup, calipers and rotors with spindle from a mini-truck and custom brake brackets and make everything fit this clean.





I took everything apart after the dry fit and cleaned and painted some parts, then greased and reinstalled everything. Ignore the brake hard lines as I've already redone them and tucked the up close to the springs. Here is the axle installed.

[sbechtold]

I've been running the Diamond rear axle for 3 months and it's been through Moab and a couple trips through the Rubicon and is working out great. I especially like having a working ebrake.

Here is a few pictures from last week going up Soupbowl. Thanks again Brian!

[wslytoy82]

damn, where did you get your money tree from!

[Penetrode Offroad]

If you dont mind me asking, how much do you have into the rear axle all said and done?

Looks tits btw!

[mobil1syn]

nice axle. couple of questions
do you retain the factory traction control also with this setup?
can you fit a 15" rim on it?
it appears that you resused the backing plate and brake assembly from the FJ, everthing else was std. solid axle parts?

[BellyDoc]

Hey Sol! That looks like it was a really good move.

Did it change the behavior of the springs at all? Are you going with a traction bar?

[sbechtold]

Originally Posted by mobil1syn

nice axle. couple of questions
do you retain the factory traction control also with this setup?

The traction control on my FJC went away when I cut the IFS off, so we did not do anything to retain it on the rear axle. Although, Brian and I discussed a couple of options for retaining the wheel speed sensors on the rear that would probably work. I've also been tinkering with something that might make the speed sensors would again someday, but that project is pretty low on the list of things to do.

Originally Posted by mobil1syn

can you fit a 15" rim on it?

Yes, I run 15x8 steel wheels.

Originally Posted by mobil1syn

it appears that you resused the backing plate and brake assembly from the FJ, everthing else was std. solid axle parts?

You are correct. FJ Cruiser backing plates, calipers, rotors, emergency brake parts and the rest is solid axle parts. The exception being the hubs are IFS hubs and there is an adapter that Brian made to bolt everything up to the full float flanges.

[sbechtold]

Originally Posted by BellyDoc

Hey Sol! That looks like it was a really good move.

Did it change the behavior of the springs at all? Are you going with a traction bar?

Thanks Jon! My stock housing was bent, so it seemed like a good time to upgrade. I've since seen another rear FJC axle that is bent and actually leaking gear oil from one of the upper link mount points on the housing. WRT the behavior of the springs, I haven't noticed anything specific, but I only did one run with the new axle and the old springs. I had Deaver build a custom set of rear leaf springs specifically for the weight of my FJC. The new springs made a huge difference in ride, stability and drive-ability. When I changed the springs I also re-valved the shocks and coilovers and adjusted the anti-rock sway bar which helped control the vehicle movement as well. The new springs, re-valving and sway bar adjustments have eliminated the side to side swaying and the ride is very responsive and not sloppy feeling, yet works extremely well on the trail at this point.

With all those changes, it's hard for me to say if the axle width really impacted the spring behavior. My guess would be No. I think I'm at a good place with respect to the suspension setup, except I now want to lower it about 3".

I run a traction bar in the rear, so I never really had any axle wrap to speak of. Here is the traction bar.

[BellyDoc]

Ha! You snuck the mount in while I wasn't watching! I didn't see it in the previous pictures (and I checked back... it's NOT there).

How is it mounted at the frame end? ... and to what?

[sbechtold]

The front side of the traction bar is mounted to the tcase/belly pan crossmember.

[GRMhick]

Very cool to see those brakes torn down.

Why did you go for such a long traction bar and not one that matched the arch of the leaf springs?

[sbechtold]

Originally Posted by GRMhick

Why did you go for such a long traction bar and not one that matched the arch of the leaf springs?

The best place for a forward mount point was the tcase cross member. The forward mount point rotates forward and backwards on the bushing as well as twists on the heim, so in theory it shouldn't bind when the suspension is twisted up. The long traction bar also provides some protection for the driveshaft as well.

[Wgasa84]

Originally Posted by sbechtold

except I now want to lower it about 3".

French the rear hanger into the frame. The front is going to be fun to keep decent up travel.

Rig is looking good bud!

[sbechtold]

Originally Posted by Wgasa84

French the rear hanger into the frame. The front is going to be fun to keep decent up travel.

Rig is looking good bud!

Thanks Chris! I'm pretty sure I can dial in the height and maintain sufficient up-travel with some shorter shackles in the rear and adjusting the coilovers down a little. I will probably need to clearance the pinch weld and firewall a little. We'll see what happens once I start playing with it.

[Wgasa84]

Originally Posted by sbechtold

Thanks Chris! I'm pretty sure I can dial in the height and maintain sufficient up-travel with some shorter shackles in the rear and adjusting the coilovers down a little. I will probably need to clearance the pinch weld and firewall a little. We'll see what happens once I start playing with it.

Remember... those 62's are designed for a LONG shackle.

Can't you push the front axle out enough to clear that firewall?

I just picked up a new set of 62's for my rig (cheap!).. though it'll be a bit before they go on. I'm shooting for 18" of vertical travel. Should be interesting, frenched hangers, long shackle, and maybe custom main leafs for Orbit Eye style joints.

[sbechtold]

I clear the firewall now, only the slightest rubbing on the black plastic flares at full stuff. I can move the axle forward, but there's really no need to at this point. I will continue to play with the setup, but everything works extremely well now, so I'm not in any rush to change anything. You will like the 62's, they flex like crazy.

[Wgasa84]

Originally Posted by sbechtold

I clear the firewall now, only the slightest rubbing on the black plastic flares at full stuff. I can move the axle forward, but there's really no need to at this point. I will continue to play with the setup, but everything works extremely well now, so I'm not in any rush to change anything. You will like the 62's, they flex like crazy.

Yes they do! It'll be nice to have new springs (current ones are 6 years old) and nice valved shocks, maybe air bumps in the future.


OK, back to your purdy build. :neener:

[geeze]

Since I'm a toydwareota newbie, what is the benefits of using the FJ brake hardware as apposed to the mini truck/LC brakes? How about using Tundra brakes?

[BellyDoc]

Originally Posted by geeze

Since I'm a toydwareota newbie, what is the benefits of using the FJ brake hardware as apposed to the mini truck/LC brakes? How about using Tundra brakes?

Well... for one thing, he already had 'em!

[sbechtold]

Originally Posted by geeze

Since I'm a toydwareota newbie, what is the benefits of using the FJ brake hardware as apposed to the mini truck/LC brakes? How about using Tundra brakes?

As Jon said, I used the OEM brake parts that came on my FJC when I bought it. That was a big plus.

I have a seen a lot of solutions that work well. A lot of people use Supra brake calipers with the built in ebrake or a transfer case ebrake or line locks for the ebrake function. I had a couple of goals that I wanted to accomplish with my braking solution.

- Must have functional rear disc brakes capable of stopping a 5500# truck
- Functional ebrake capable of holding the truck on an incline
- Fit within a 15" wheel
- Mainly a non custom bolt on solution for the braking components
- Reuse existing parts if possible

This is a very simple solution that uses factory parts that are readily available and met all my requirements. The cool part is that Brian now has another solution that people can buy. We did look at the Tundra brakes, Revolution "Mr. Parker" brakes, dual calipers, etc. None of those solutions is as simple as this one.

[Pook]

Nice FJ. I'd like to buy the wife one.

[BellyDoc]

If I'm recalling correctly, you had already gone to a custom rear drive shaft when you did the dual case crawl box because of the rear output flange moving backward.

Now that you've swapped out the rear third member for the 80 series to get a 9.5" ring gear, did you also end up with a longer snout? It looks a little bit longer in your comparison pictures, but it's also resting on the ground at a different angle.

The bottom line is: did you have to shorten the drive shaft AGAIN?

[sbechtold]

The pinion length on the 9.5" is the same as the 8" elocker, so I did not have to shorten the driveshaft.