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Rear axle swap?

Apogee

Contributor
Bronco Guru
Joined
Nov 26, 2005
Messages
6,159
If by "bolt-in" you mean "welding and fabrication required", then absolutely...otherwise not really. The overall track width is the main concern if you don't want to have to narrow a rear end, so that means looking for something in the ~58" range that's going to do the job. The EB rear ends were super popular with the Mustang guys, because a lot of them had Ford 8" rear ends, so that was a natural swap. If I were looking in the yards, I'd be looking pretty hard at the Ford 8.8 from the mid-90's Ford Explorer applications with 31-spline axles, limited slip options, disc brakes, etc.
 
OP
OP
T
Joined
Nov 5, 2024
Messages
8
If by "bolt-in" you mean "welding and fabrication required", then absolutely...otherwise not really. The overall track width is the main concern if you don't want to have to narrow a rear end, so that means looking for something in the ~58" range that's going to do the job. The EB rear ends were super popular with the Mustang guys, because a lot of them had Ford 8" rear ends, so that was a natural swap. If I were looking in the yards, I'd be looking pretty hard at the Ford 8.8 from the mid-90's Ford Explorer applications with 31-spline axles, limited slip options, disc brakes, etc.
May I pick your brain?
 

sanndmann3

Contributor
Bronco Guru
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Jun 13, 2007
Messages
1,783
I could be wrong but medium duty Bronco 9 " rear will accept Explorer 8.8 rear disc brakes. I redrilled the rotors for the 5x5.5 bolt pattern.
Didn't bother with emergency brake though...
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
35,507
No.

No junkyard axle will bolt in.
Stuff can be adapted, but nothing is really that good. The Explorer is pretty close, but it would require all mounting points be fabed, driveshaft will not bolt up and will require custom fab work. And in the end the wheel bolt pattern will be wrong as well.
 

Apogee

Contributor
Bronco Guru
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Nov 26, 2005
Messages
6,159
I could be wrong but medium duty Bronco 9 " rear will accept Explorer 8.8 rear disc brakes. I redrilled the rotors for the 5x5.5 bolt pattern.
Didn't bother with emergency brake though...

That is correct, as they both share the same 2.00" x 3.56" rectangular flange pattern, 3/8" retainer bolts and 2.50" brake offset dimension. The Ford 8.8 is a c-clip semi-float axle, whereas the Ford 9 has the bolt-in semi-float axles, so you need to account for the axle retention with the backing plates, and there are a few different methods for doing so, some of which don't require the backing plates to be captured on the axle by the bearing.

Advantages to the 1995-2001 Explorer 8.8 over the 9" would be that it has a higher pinion height, so driveshaft angles can be improved, and it's more fuel efficient due to the more direct contact angle between the ring and pinion. Some of the Explorers apparently even came with 4.10 gears, but they seem to be less common than the 3.08, 3.27, 3.55, 3.73 options. That said, aftermarket gear support isn't bad and you can get 4.56 and 4.88 if needed. While the Trac-Lock is not my favorite limited-slip, it works pretty well and doesn't seem to have the same issues associated with the Trac-Lock for the 9", which I have had the pleasure of personally blowing up under my '77 F150. Last but not least, disc brakes ready to rock and roll and fit inside Ø15" wheels. FWIW, the specs of the pre-1995 Explorer 8.8's are similar, but came with drum brakes.

Disadvantages would be wrong leaf spring spacing, so the pads will need to be moved, as will the shock mounts, and the wheel pattern on the axles/brakes is 5x4.5. You can either machine the axles and rotors to match the 5x5.5 Ford pattern or purchase replacements through the aftermarket with the proper pattern.
 

Jedeka

Contributor
Full Member
Joined
Oct 5, 2014
Messages
258
I bought an Explorer rear disk brake kit from Quick Performance.
 

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Timmy390

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Bronco Guru
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Jan 1, 2011
Messages
5,722
Loc.
Conway, AR
Doesn't JBG sell a kit with all the weld on brackets? Thought I seen one at one time but then again I drink so.....

Tim
 

SteveL

Huge chevy guy
Joined
Jun 24, 2001
Messages
11,776
Loc.
Hawthorne ca
If you're looking for a no fab work bolt in rear end call currie. Pick your .housing and any other components and they will build you a bolt in rear. most of thei.pr stuff use the explorer rear disc
 

Jedeka

Contributor
Full Member
Joined
Oct 5, 2014
Messages
258
I read your post again and see that you want a complete housing. Quick Performance can build a custom bolt-in housing for you.
 

Yeller

Contributor
Bronco Guru
Joined
Mar 27, 2012
Messages
6,745
Loc.
Rogers County Oklahoma
Wild horses sells all if the components that bolt together and bolt in for a completely brand new axle, or a mix and match of your existing parts. They also sell disc brake kits for your existing axle.

However as stated above there are no bone yard bolt in axles
 

ep67bro

Contributor
Bronco Junky
Joined
Aug 28, 2008
Messages
3,760
Loc.
Easton, MD
Why swap the entire axle? Just buy a disk brake conversion kit from one of the vendors and get your disk brakes for a lot less work than everything needed to swap the entire axle. And it would probably cost less in the long run.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
35,507
I was assuming you were looking for an axle from a donor vehicle, just go to the junkyard and get one type of bolt in.
If you go aftermarket, the sky is the limit. Most all of the big aftermarket axle makers can build you anything you can dream.

Food for thought, rear disks are not super wonderful in a Bronco. Often more of a bling check item than a functional upgrade. The original drums are known for being a better park brake. Fuctionality of the rear drums is just fine for a Bronco. No real increase in braking capacity, feel, or much of anything with a disk upgrade. Not sure what your expectations are with going to rear disks.
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,666
Loc.
Upper SoKA
Unsprung weight was why I went with rear discs. A significant drop in weight compared to the drums that the D60 came with.

Discs are also better with repeated water crossings. Not something we desert dwellers have a lot of experience with (Afton Cyn anyone?), but I've done enough of those in the avatar (ACVW drums in particular suck badly) to appreciate the difference.

Based on my singular experience with one, I see the 8.8 as a really great way to keep a boat from drifting away and not good for much else. Is it even used in anything new these days?
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,666
Loc.
Upper SoKA
Forgot to add that the Explorer RDB conversion kits are sold by many vendors out there. I bought one such kit to try to use on Snowball's D60 and it won't work (spinning parts want to be where stationary parts already are). Had I used a 9" with the "Torino" housing ends and housing to axle flange spacing they would have fit. Can have your existing housing altered with the different housing ends, but you'll need to buy new axle shafts as the spacing isn't easily changed. Fortunately that is not as expensive as it used to be. My RDB kit came from Moser.
 
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