Best route for getting 31 spline axles

[OsideDave]

Hello all, my 1974 stock bronco 9" housing is original and has been welded a few times over the years plus is has had 3rd member setup (4.56 gear and Detroit locker) since the mid 1980's. With a fresh 351W and 35's going on a few years ago, I am concerned that I will snap an axle on the trail and be stranded - have done this before on first bronco. With this in mind I don't tend to gas it much when wheeling and that's no fun...

What's the best route price wise to get a complete new housing equipped for disc brakes, 31 splines (or higher?), new gearing and perhaps an ARB or ? I'd like to get a complete new setup and sell my housing to recoup some of the costs. Open to ideas!

 

[Apogee]

Best is certainly debatable, but one option would be to find a Ford 8.8 from an Exploder, put the gearing and locker of your choice in it and be done. They're c-clip, but they're stout rear ends, have 31-spline axles in stock form and are more efficient than the 9" due to the higher pinion location relative to the ring gear.

Cheapest option...find one that someone else has built and is selling, letting them take the loss.

I'm building the full-width version of what you describe, starting with a full-width F150 housing. The housing ends were a bit rough, so I took it as an opportunity to truss it with the Ruff Stuff back brace and weld on new housing ends, which not only addressed the issues with the old ends, but also allowed me to make sure the housing was straight. I plan to reuse the factory 31-spline axles, however the ARB alone is $1k, so with all the little bits and pieces, it's far from cheap, but hopefully will work well and last a long time for what I do.

 

[OsideDave]

So an 8.8 is a good as a 9"?

 

[Dannyboy71]

Did you take a look at Currie enterprises?

 

[OsideDave]

I'd love to go Currie but that seems to be the most expensive route...I should check them though

 

[70_Steve]

So an 8.8 is a good as a 9"?

An 8.8 would be a downgrade.

I'd love to go Currie but that seems to be the most expensive route...I should check them though

Not sure what kind of a price break you're looking for considering your list includes:

• New 9" Housing
• New 3rd Member w/ARB
• 31 Spline Axles
• Disk Brakes

Do you want a fully assembled differential or can you do some assembly? If you can do some assembly, how much?

I just did most of this to my rear. All new 3rd member that included a cheap Ebay aluminium case, new Detroit Locker, new Yukon gears and install kit. I figure I've got around $1200 in it, and I did the assembly.

Also did the Explorer disk brakes, but used Wild Horses 31 spline Dutchman axles, made for this conversion to set the brakespace at 2 1/2". At $400 these axles are worth every penny. Besides being beefier than the Currie 31 spline axles they replaced, They come with SET20 tapered roller bearings already installed, they are machined with more attention to detail (damn pretty!!), plus, since they are designed for the correct brakespace, the brakes installed without an issue.

Did the Pick&Pull for the Explorer brakes, but did spring for new rotors, pads, hoses and parking brake shoes. I redrilled the rotors to 5x5.5 myself, so they still only cost $20 apiece. All together, I've got right at $100 in the disk brakes.

So ballpark the cost of my mostly-new rear at $1700-1800 using my existing housing. Seems like I've seen new 9" housing around the $400 mark. So... $2200 if you do the assembly? Oh, plus the difference between the Detroit and the ARB.

 

[techlaf]

Currie now sells a different tube diameter than stock broncos so you might have to change your U-bolts.

 

[bronconut73]

An 8.8 would be a downgrade.

Not sure what kind of a price break you're looking for considering your list includes:

• New 9" Housing
• New 3rd Member w/ARB
• 31 Spline Axles
• Disk Brakes

Do you want a fully assembled differential or can you do some assembly? If you can do some assembly, how much?

I just did most of this to my rear. All new 3rd member that included a cheap Ebay aluminium case, new Detroit Locker, new Yukon gears and install kit. I figure I've got around $1200 in it, and I did the assembly.

Also did the Explorer disk brakes, but used Wild Horses 31 spline Dutchman axles, made for this conversion to set the brakespace at 2 1/2". At $400 these axles are worth every penny. Besides being beefier than the Currie 31 spline axles they replaced, They come with SET20 tapered roller bearings already installed, they are machined with more attention to detail (damn pretty!!), plus, since they are designed for the correct brakespace, the brakes installed without an issue.

Did the Pick&Pull for the Explorer brakes, but did spring for new rotors, pads, hoses and parking brake shoes. I redrilled the rotors to 5x5.5 myself, so they still only cost $20 apiece. All together, I've got right at $100 in the disk brakes.

So ballpark the cost of my mostly-new rear at $1700-1800 using my existing housing. Seems like I've seen new 9" housing around the $400 mark. So... $2200 if you do the assembly? Oh, plus the difference between the Detroit and the ARB.

This /\/\/\ is the way to go Bro.
Save a lot of money. Get super good axles. Cheap OEM brakes that really work and look great.
If You have the '74 medium bearing axle this will be even cheaper.
Check out Wild Horses Bud. They have what you need.

 

[badmuttstang]

Ruffstuff has a new 9" Axel coming out not sure on price but they are giving one away at the raffle for the nwbr. Sorry though it's mine I already laid claime to it;D

 

[nvrstuk]

x2 what Apogee posted.

I've spent $ building my 9" up after grenading several. The 8.8 Exploder, check it out on other sites, you will be impressed! Are you running less than 500HP? If so, go Exploder, hands down- check it out.

After a while even a nodular will still have weak links... Daytona, etc...

I've finally gone to Truehi9, 35 spline Dutchman's, etc to eliminate the pinion thrust issues with a typical 9"... I run super low gears and a pretty stout 418 stroker tho.

 

[badmuttstang]

I will add x3 on the 8.8 if you do some mods to it they can handle some abuse and they are lighter. Plenty of Mustang guys run them with high horse power numbers on the drag strip with no problems (gee I don't know how I would know that) but that's not really the same as offroad so depends on driving habits and horse power for how much you would have to put into it.

 

[Apogee]

I will add x3 on the 8.8 if you do some mods to it they can handle some abuse and they are lighter. Plenty of Mustang guys run them with high horse power numbers on the drag strip with no problems (gee I don't know how I would know that) but that's not really the same as offroad so depends on driving habits and horse power for how much you would have to put into it.

I see more 8.8's under Jeeps than anything else, but plenty under Rangers, F150/BB's, Toyotas, Sammy's, etc, some of which are pushing big rubber with decent HP/torque numbers. While I fully understand why the 9" is technically superior in several ways and while I prefer positively retained axles over c-clips, the Ford 8.8" is one of my favorite c-clip semi-float rear ends available.

 

[fordguy]

what are the wms to wms, or backing plate flange to flange dimensions on the explorer versus the stock bronco

 

[fordguy]

I am getting ready to build a nine inch with exploder disc brakes, will come back with an estimate. not sure what carrier I am running, but will decide. I bad a mountaineer sold the 8.8 but kept the disc brake stuff.

 

[Apogee]

what are the wms to wms, or backing plate flange to flange dimensions on the explorer versus the stock bronco

59.5" WMS-WMS for the Explorer 8.8 IIRC, so basically an inch wider than the EB 9".

 

[OsideDave]

I didn't realize a Ford ranger axle would be desirable. My buddy broke his 2 times and had the axle slide complete out on to the street.

 

[badmuttstang]

I see more 8.8's under Jeeps than anything else, but plenty under Rangers, F150/BB's, Toyotas, Sammy's, etc, some of which are pushing big rubber with decent HP/torque numbers. While I fully understand why the 9" is technically superior in several ways and while I prefer positively retained axles over c-clips, the Ford 8.8" is one of my favorite c-clip semi-float rear ends available.

Yeah it's a very common swap for all those guys especially since its cheap if c-clips are an issue you can swap out the ends with c-clip eliminators. One benefit to the explorer or any of the other 8.8 c-cilp disc brake axles is you really have to do some serious damage to have an Axle come out if it fails.

 

[TN1776]

Currie is somewhat close to you, so unless you go the junkyard route - if you are not paying for shipping they may be a good option if you stay with the 9". I bought their Bronco-specific housing, 31 spline axles, and their brakes late last year to replace my small bearing housing. I had the housing powder coated, dropped my center section in, and assembled it. Pricey sure, but I am happy with this upgrade.

 

[Apogee]

I didn't realize a Ford ranger axle would be desirable. My buddy broke his 2 times and had the axle slide complete out on to the street.

Most Ford Rangers were supplied with a 7.5" ring gear rear axle, not the 8.8, so that's probably what your friend was breaking. As for the axle sliding out once it breaks, it was probably a drum brake axle as well, whereas a disc brake application would need to literally rip the caliper off the backing plate for the axle to slide out of the housing...and while possible, it takes some serious abuse to do that to a 31-spline axle.

I've seen Ford 9" axles slide out as well due to loose bearing retainers, so it's not like each isn't without their pros and cons.

 

[sykanr0ng]

Yeah, the Jeepers put in 8.8's, but if you look at the stock axle they started with anything stouter than tinfoil and bubblegum is an upgrade for them.

Seriously, they grab our throw-aways and use them as an upgrade.
So pointing at them and saying "See, they do it" isn't really much of an argument in favor of it.