Early mustang 6 cylinder diff

[BJB]

Greetings,  I don't own a Mustang but I purchased an early Mustang 3.20 ratio diff with the intention of installing the crown wheel and pinion into my XP utility diff which is to be fitted into my 66 Fairmont, just so I achieve 5 stud bolt pattern and obtain a decent highway ratio.

So far so good as the early Mustang  7.25" CW and P look identical to the early Borg Warner Australian diffs. 

I have been advised to replace the diff bearings ( and the axle bearings also ) before reassembling.  I am fairly confident that the Aussie bearings will be identical to the US variety in specifications but I would prefer to purchase the US bearings forthe US parts.  Has anyone reco'd a 6 cylinder Mustang diff and if so what bearing kit did you use, or individual parts if not a kit.




Bruce
Victoria.

[Ash]

It wont be a Mustang 6cyl diff if it is 5 stud hubs. The 6cyl were all 4 studs.

And coming from a 6cyl Mustang owner, I can tell you it is same to assume that nothing will be the same as Aussie Falcon parts. They could be but from my experience so far they are very close but often not the same.

Are there any tags on the diff? I'd be looking for that and emailing some US driveline guys and asking what they can supply in kit form. It'll be cheap, Australian prices wont even be close even with the high postage costs from the US.

[scedd1]

Greetings,  I don't own a Mustang but I purchased an early Mustang 3.20 ratio diff with the intention of installing the crown wheel and pinion into my XP utility diff which is to be fitted into my 66 Fairmont, just so I achieve 5 stud bolt pattern and obtain a decent highway ratio.

So far so good as the early Mustang  7.25" CW and P look identical to the early Borg Warner Australian diffs. 

I have been advised to replace the diff bearings ( and the axle bearings also ) before reassembling.  I am fairly confident that the Aussie bearings will be identical to the US variety in specifications but I would prefer to purchase the US bearings forthe US parts.  Has anyone reco'd a 6 cylinder Mustang diff and if so what bearing kit did you use, or individual parts if not a kit.


Bruce
Victoria.

Have a look for a Chryslera Centura diff.
Then you get a 5 stud ford pattern that is strong enough for a V8 in everyday use and should be the right width for your ute.

[shaunp]

It wont be a Mustang 6cyl diff if it is 5 stud hubs. The 6cyl were all 4 studs.

And coming from a 6cyl Mustang owner, I can tell you it is same to assume that nothing will be the same as Aussie Falcon parts. They could be but from my experience so far they are very close but often not the same.

Are there any tags on the diff? I'd be looking for that and emailing some US driveline guys and asking what they can supply in kit form. It'll be cheap, Australian prices wont even be close even with the high postage costs from the US.

XP utes had 5 stud wheels, while the rest had 4 like a mustang, just measure the bearings any bearing service will have them I suspect.

[BJB]

Just to clarify some issues, the donor  Mustang diff was a 4 stud diff with a 3.20 CW & P.  The tag indicates it is a 3.20 centre.   It has been since successfully transplanted in the XP Ute diff which has the 5 stud wheels.  The Borg Warner OZ CW & P are a direct copy of the Mustang 7.25 items.  Bearings are the same , crush tube for the pinion is the same.  Ford OZ just copied the yank specs.  I now have a 5 stud diff which will bolt up with hardly a fuss.  I plan to use the XP Ute springs also. 

The XP Ute diff is different to the XP Falcon sedan diff in that the axle flange is larger in order to take the rear 10" drum brakes, and the axle bearings are larger/wider. Falcon sedans use 9" brakes on the rear and they are not interchangeable. The early Mustang 6 cyl diff has 9" drums but the axles are longer. 

I am yet to finish the diff as I am obtaining XF rear brakes which will bolt straight up ( the brake shoes are the same as the XP Utes)  I need to paint up the springs and obtain new suspension bushes for the rear. 

Will let you know how it goes once I bolt it up.  I am also installing front XY vented rotors on the XP Fairmont disc spindles ( same bearings as the XY) and will be using Girlock callipers from a WB Holden as they share the same bolt hole specs. 

I have a second Ute diff which is the worse of the two that I obtained ( it had been drowned in a dam or flooded out) and I am just mucking around with it fitting  XE rear rotors and callipers that bolt up.  ( the calliper mount needs to be rotated 45 degrees to clear the springs.  No drilling at this stage , everything just bolts up. )  Even the XF breather tube screws into the XP Ute  axle,  Ford changed nothing over the years.   





XF brake shoes are  the same as XP Ute shoes.


This Ute diff now has the Mustang centre and is painted.  Awaiting the XF brakes.



That said, it would be a fairly simple process now to install 2.79 or 2.83 or 3.00 7.25" Mustang early centres for better cruising. ( if you could get them of course)  It has been a great learning curve for me as I knew jack shizen about these diffs until I started pulling them apart and putting the verniers on the parts.  There is a lot of Mustang DNA in the Falcon diffs.

XP Ute bearings were obtained from a local bearing shop and matched up to the Mustang  bits perfectly. 

[Ausfox]

BJB,
You mightl find that your handbrake cable can be slotted into the XF caliper lever if you mount your outer  handbrake cable brackets accordingly.

 Dont think there is any difference in early falcon handbrake cable lenghts.



This is a pic of a Mustang one I did about ten years ago and used a handbrake cable clevis from a Mazda, but have since found it unecessary.



Also you will need A new machined thicker bearing retainer  to get the caliper to line up with the disc and the longer XF studs as the disc is thicker than the drum.

I also swapped the caliper mounting bracket side for side,  calipers now to the rear and no clearance problems.

P.S.  You caliper is upside down.

[BJB]

Thanks for that.  The Mustang diff is a few inches wider so the calliper may clear the spring but on the early Falcon the calliper asembly has to to be rotated  somewhat to clear fouling the bumpstop and spring.

Calliper in the wrong position.  Are you sure>  Did you use the XE set up on your Mustang ?

[Ausfox]

"Calliper in the wrong position.  Are you sure>  Did you use the XE set up on your Mustang ?"

Yes. On an XF caliper the bleed screw is on the same side as the Banjo fitting for the hose, ie on the top of the caliper.

In your pic the banjo hose fitting is on the bottom.  You won't be able to bleed the caliper

[BJB]

Thanks Ausfox, I realise now that when I set it up the first time it was upside down.  I went to the wreckers today and found a wagon with the same set up and confirmed my error.

I realised that the alloy calliper housing is 6mm thick as compared to the standard drum brake backing plate of 3mm, which means I would have an extra 3mm of end float.  I have ordered some stainless steel spacers of 3mm thickness that will go between the bearing and the axle seal which should take up the slack.  The disc brake rear end is just for shits and giggles at his time as I have 10" XF drums to mate up to the XP ute diff at this stage. The XF  drum set-up is a bolt on improvement .


The mustang diff is about 1.5cm wider between the axle flange and the spring perch than the XP.  If I went disc brake rear end I think I would have to rotate the callipers and housing  45 degrees upwards in order to clear the spring and not interfere with the bumpstop.   
 

[ashley47]

Hi BJB, are you using the standard xp 14in rims with the WB Girlock calipers? I was thinking of going down the same path but was unsure of the clearance.

[BJB]

I will be using 14" GXL Fairmont rims.  I am yet to fit the WB callipers to the XP disc brake spindles.  When I do I will post up.  You can run the standard 14" XP rims with the HQ callipers though. 

Bruce

[BJB]

Well since then I installed the 5 stud utility diff into the XP utilising a 3.20 Mustang centre.  10" XF brake backing plates and XP drums ( smaller centre hole than the XF)

It has worked out well.  Diff is quiet the ratio is the same as the standard XP Fairmont , larger 10" drums makes for better braking and I have fitted GXL 5 stud rims.



In the mean time I purchased a 7.25" Equa-lok LSD from the US and as well as a '67 Mustang 2.83 diff centre.  These are being installed in another XP utility diff.

As I won't be running a V8 the diff will handle it .


L to R .      XP standard utility carrier, '67 Mustang 2.83 centre and Ford Qua-lok LSD carrier.



You can see a scoop that I take feeds the oil into the carrier


Sat it in the housing to see how it fits....it fits.

[Richstang]

I just relisted on evelbay my 1963 XL ute diff and front hubs, I was planing to run the 5 stud diff with the centre swapped into it from my 6 Mustang.
Going with a roller 302 now so having built a 9"
Selling the diff, axles and front hubs for 5 stud all round.

[BJB]

2.83 centre with Equa-lok fitted. 

Previous owner sent me the diff tag.