300 M rear axles and flanges

[smittycrusher]

I got most of my 300m rear axles and rear axle rebuild done. Thank you to @cruiseroutfit for the RCVs and rebuild kit. My rear axle had never been opened up in it’s 23 year, 285k mile history. I was blown away at how good everything looked in there. There wasn’t any grease left, but the oil bath seemed to treat the bearings very well as they looked fantastic. I replaced the bearings anyways (and decided to stick with two bearings per hub and forgo the weight savings ). Install was super easy and I did decide to take advantage of the extra dowel pins. Still need to pick up my new set of cone washers tomorrow before I tighten everything down.

 

[Rivman1243]

I got most of my 300m rear axles and rear axle rebuild done. Thank you to @cruiseroutfit for the RCVs and rebuild kit. My rear axle had never been opened up in it’s 23 year, 285k mile history. I was blown away at how good everything looked in there. There wasn’t any grease left, but the oil bath seemed to treat the bearings very well as they looked fantastic. I replaced the bearings anyways (and decided to stick with two bearings per hub and forgo the weight savings ). Install was super easy and I did decide to take advantage of the extra dowel pins. Still need to pick up my new set of cone washers tomorrow before I tighten everything down.

View attachment 2187974

How did you drill the holes for the extra dowel pins?

 

[smittycrusher]

How did you drill the holes for the extra dowel pins?

I just mounted the flanges to the hub and put that on a drill press and used the flange holes as guides. The kit comes with the proper drill bit for the job. I also used a drop of blue loctite in the holes before gently hammering in the pins. I have no idea if this is the best way to do it, but it was simple and effective.

 

[jcardona1]

On the topic of hub stud/dowel pin upgrades, I looked at several alternatives over the last few weeks before decided I'm not going to invest any more money in Toyota axles and will eventually go the one-ton route as I want to run bigger tires.

Anyway, found a couple neat solutions that some might find interesting. Having an external-mounted drive flange or locking hubs held together with tiny studs and pins is a big weak point. Sure you can drill and tap for 7/16" SHCS but there is a lot of force being applied the hub/drive flange assembly.

I came across this machined hub/drive flange made by PJs Offroad. You still keep the studs/pins, but notice how the drive flange has splines which lock into the hub. I'm sure this provides a nice strength upgrade.

But I was really intrigued by the Trail Gear studless hubs which eliminate the entire hub+drive flange assembly. Lots of guys on Pirate run these on the minis and they wheel the piss outta their rigs. I was able to find 2 instances of these hubs used on an FJ80 axle. From what I understand it requires a mini truck spindle and different brakes. The mini truck spindles are about 1/4" longer than the FJ80 spindles so apparently there is a bit of machining required for a spacer or bushing of sorts. I have not been able to find pics of exactly what is required. But in my opinion this seems like the ultimate hub upgrade for the FJ80 front if you plan on sticking with Toyota axles. But from my perspective, this was too much hassle to still end up with weak overall drivetrain so I've abandoned the idea. Would love to see someone else try it though.

Trail Gear chromoly mini truck spinde + Trail Gear Studless Hubs + 5th 4Runner rotors and calipers. 100% Toyota Beef.

These guys ran a similar setup but with smaller rotors from earlier Toyota models:

 

[bug616]

I came across this machined hub/drive flange made by PJs Offroad. You still keep the studs/pins, but notice how the drive flange has splines which lock into the hub. I'm sure this provides a nice strength upgrade.

Splined hubs.....

forum.ih8mud.com

 

[jcardona1]

Splined hubs.....

forum.ih8mud.com

Nice, did you ever find out what they cost? Their website has no info and looks like it was designed during the days of Netscape Navigator.

 

[bug616]

Nice, did you ever find out what they cost? Their website has no info and looks like it was designed during the days of Netscape Navigator.

No I never enquired. I’m not upgrading till next year, so will enquire then and either go with these or RCV

 

[canadian bum]

Awesome thread. Anyone running the 32 spline shafts? I'm going to build a hybrid 80 rear with the 100 third and the 32 spline shafts in the future. I got a third lined up and a few 80 rears kicking around.

 

[HDJdreams]

Awesome thread. Anyone running the 32 spline shafts? I'm going to build a hybrid 80 rear with the 100 third and the 32 spline shafts in the future. I got a third lined up and a few 80 rears kicking around.

My plan too!

 

[Road Apple]

Assuming you're doing the 7/16" stud drilling/taping on a mill?

Wonder if there is a market for a pre-made 8x rear hub with 7/16" studs, 6 x dowels and matching RCV 300M flanges sans cone taper?

For those scared by the SAE dimensions, we could do 10mm studs, perhaps with or without cone taper.

All it takes is ~100 committed customers and we can get RCV to do a production run of whatever we want.

Did anything ever come of this. Read to buy RCV axles with 7/16" studs. Do you carry them or can you mill them?

 

[baldilocks]

Did anything ever come of this. Read to buy RCV axles with 7/16" studs. Do you carry them or can you mill them?

How many times have you broken hub studs.

 

[Road Apple]

How many times have you broken hub studs.

I’m building a truck for rock crawling the Sierras, mainly the Tahoe area. My goal is to prevent breakage before it happens by strengthening the weak areas.

Cruiser outfitters just explained that RCV makes drive flanges with 6 dowel pins. No longer any need for larger hub studs. Ordered

 

[baldilocks]

I’m building a truck for rock crawling the Sierras, mainly the Tahoe area. My goal is to prevent breakage before it happens by strengthening the weak areas.

Cruiser outfitters just explained that RCV makes drive flanges with 6 dowel pins. No longer any need for larger hub studs. Ordered

Wheeled the sierras for years on 37’s and never broke stock equipment. I have, however, upgraded to ARP studs recently everywhere but give it no thought. Maintenance is the key. Sensible use of throttle helps too.

 

[Road Apple]

Wheeled the sierras for years on 37’s and never broke stock equipment. I have, however, upgraded to ARP studs recently everywhere but give it no thought. Maintenance is the key. Sensible use of throttle helps too.

I don’t like wheel spin in the rocks either. A few members talk about shearing hub studs on a regular basis, so I’m being overly cautious. I bought APR studs as well for the hubs and knuckles. I’m regearing to 4.88’s, rebuilding the knuckles, and installing RCV 30 spline axles, so it’s not much trouble to install RCV drive flanges while I’m at it. Installing underdrive and 3.1:1 low range t-case gears to increase control. I’m baselining the drivetrain basically. I’ve had this truck for 8 years, we’re moving close to the trail, so the wife gave the green light to build the truck right. Cry once. Trying to avoid crying on the trail later. Already baselined under the hood. Now working on tires/wheels, suspension, armor, and drivetrain. Thanks for the input. Appreciated

 

[GOTLOCKED96]

So I purchased these, 300M Axles.

Ultimate CV Axle Set for Land Cruiser 80 Series ('91-'97) - 30 Spline 300M Shaft Upgrade

SKU: CVJ2474-30T-300M

Do I also need to buy these?

RCV 4340 Drive Flange Set for Toyota Solid Front Axles

 

[Road Apple]

I bought these RCV drive flanges from Cruiser Outfitters. They have 6 dowels. OEM has 2.
TOY-DF RCV Drive Flange Kit

 

[GOTLOCKED96]

I bought these RCV drive flanges from Cruiser Outfitters. They have 6 dowels. OEM has 2.
TOY-DF RCV Drive Flange Kit

Yeah, but i'm wondering if what I bought is 30 spline of the flange end and if so, if it doesn't come with these.

I'd assume they would put "*requires 30 spline flange kit" if that was the case.

 

[Road Apple]

Yeah, but i'm wondering if what I bought is 30 spline of the flange end and if so, if it doesn't come with these.

I'd assume they would put "*requires 30 spline flange kit" if that was the case.

If you're buying from Cruiser Outfitters, they do not come with the 30 spline axles.
I bought both axles and flanges separately today. The part is TOY-DF RCV Drive Flange Kit.

FYI, when I asked for the RCV 300m axles, they steered me away from them. They said the harder axles wear faster and since I'll be driving the
freeway to the trailhead, they suggested back stepping, which are also 30-spline, just not the harder 300m material.
Surprised me, but I bought the RCV 30 Spline 4340 Axle Set. They said customers don't twist them.

 

[GOTLOCKED96]

If you're buying from Cruiser Outfitters, they do not come with the 30 spline axles.
I bought both axles and flanges separately today. The part is TOY-DF RCV Drive Flange Kit.

FYI, when I asked for the RCV 300m axles, they steered me away from them. They said the harder axles wear faster and since I'll be driving the
freeway to the trailhead, they suggested the back stepping, which are also 30-spline, just not the harder 300m material.
Surprised me, but I bought the RCV 30 Spline 4340 Axle Set. They said customers don't twist them.

Well guess I need to do more research. I never heard of this. Granted it a weekend rig now.

Thanks for the heads up. Any one have any input?

 

[Road Apple]

Well guess I need to do more research. I never heard of this. Granted it a weekend rig now.

Thanks for the heads up. Any one have any input?

FYI - I bought different drive flange that are drilled for 6 dowel pins, making it less likely to shear hub studs.