7.25" Differential Rebuild

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Route--66--
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7.25" Differential Rebuild

Post #1 by Route--66-- » Tue Aug 20, 2013 5:38 pm

Hi all

As you may have seen in other posts I think the play on my diff is excessive so I've decided to totally rebuild;
http://www.youtube.com/watch?v=NN3wORp-ZnM

I have located some NOS gears for the inside of the carrier (2 pinion and 2 side gears) plus pin for $206 + postage. (ok price..?)

I am also looking at this kit - which I assume is the correct one for my 1965 7.25";
http://www.rockauto.com/catalog/moreinfo.php?pk=4438635&cc=1333370

Just wanted to double check with you guys that this is the correct kit and with this and the internal gears that I haven't forgotten anything!

Obviously I haven't included ring & pinion gears. Mine I think are a bit worn but not horrendous so think I'll keep them unless I come across a good 2.83 before the rebuild.

Cheers!
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #2 by Varilux » Tue Aug 20, 2013 8:07 pm

Hats off to you for thinking rebuild instead of replace! I did a bit of searching for parts when my 7.25" bought it last year- and finally decided to just look for an 8" to swap in. Mine was in far worse shape than the one in your video however (yours is probably salvageable :^).

Took less than a week to find a guy swapping up to a 9" on Craigslist. Including the cost to have the back end of the driveshaft refit with a larger U-Joint, it was about $200 and took me about an afternoon to swap out (of course, I also put in some new leaf springs as well- which increased the financial scope of the project :^).

Just saying, unless you are trying to stay as stock as possible, the 8" is going to be tougher, is super-easy to find parts for, and the rear drums will be slightly bigger as well. Good luck with the rebuild (would like to see a video of the new one once installed).
'65 Coupe - Silver Smoke / Red Interior : L6-200, T-5spd, 3.55 rear, Offy 3x1 head, DUI HEI ignition, CI stainless dual header, dual exhaust (Magniflows), Chockostang disc brakes, export brace, 1" front sway, A/C (Sanden compressor), GT Gauges + Rally Pac, Dynacorn fiberglass hood, MB Old School 15x7" wheels, Humphugger Console, USA-66 AM/FM, Sony amps (500w 12" sub + 200w)
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Re: 7.25" Differential Rebuild

Post #3 by rbohm » Tue Aug 20, 2013 8:49 pm

8) the kit shown in the picture at rock auto is just a stock photo and doesnt necessarily represent the parts in the kit. rebuilding the rear end isnt hard to do though, but you do need a few specialized tools, a dial indicator and magnetic mount, a torsion style torque wrench(it reads instant torque as you turn the tool so you can get a reading on preload), and click type torque wrench, and a pair of dial calipers to measure washer and shim thicknesses.
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Route--66--
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Re: 7.25" Differential Rebuild

Post #4 by Route--66-- » Wed Aug 21, 2013 3:49 pm

Thanks guys - I'd really love to do the rebuild myself - really enjoy doing jobs like that but after looking in my box of talent I don't think there's enough in there to get all the tolerances / shims correct!.. so will no doubt take it to an axle specialist..
shame really unless there's a very very explicit step by step guide somewhere..

I know about the one on mustang monthly article http://www.mustangmonthly.com/howto/mump_0912_1965_ford_mustang_convertible_rear_axle_rebuild/pinion_gears_and_differentials.html but that doesn't prescribe how / where to put shims etc.

How many / what are the major hard parts to re-doing the lot myself including changing spider gears inside the diff itself?..

as for 8" yeh the only prob is finding an axle in the uk to start with then the prob with all new wheels / tyres for 5 stud ..

Cheers loads!
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #5 by rbohm » Wed Aug 21, 2013 3:54 pm

8) rebuilding a differential itsnt hard, in fact most people with the standard two thumbs can do the job easily. the devil is int he details though, and the details in this case is getting the shim and preload adjustments right. if you take your time with the right tools, you can do this.
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Re: 7.25" Differential Rebuild

Post #6 by tody » Wed Aug 21, 2013 4:36 pm

i'd use 382K kit from here:
http://www.ratechmfg.com/fordstandard.htm

the shop has a very high reputation, uses quality parts and does ship internationally, iirc.

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Re: 7.25" Differential Rebuild

Post #7 by Route--66-- » Fri Aug 23, 2013 3:16 am

Cheers
Is there any guide that walks you through it at all and that would explain exactly how to set everything up - eg the '65 mustang / comet etc workshop manual..?
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #8 by rbohm » Fri Aug 23, 2013 3:39 am

8) a ford shop manual would;

http://www.amazon.com/Comet-Falcon-Fair ... hop+manual

this one in one cd-rom
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Re: 7.25" Differential Rebuild

Post #9 by Route--66-- » Fri Aug 23, 2013 12:30 pm

ah yeh that's the one I meant!
Have been procrastinating about buying that for ages so will get it tonight and have a nose!
Cheers
D
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #10 by Route--66-- » Wed Aug 28, 2013 1:10 pm

Cheers, Bought the electronic manual!
Daft question I know but I assume from the list below my diff has to be the 1st in this list; C2AZ-19590-A (integral carrier)
.. . . (what actually does integral carrier mean as opposed to the others ???)
Image

Cheers!
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #11 by rbohm » Wed Aug 28, 2013 3:50 pm

8) the carrier is the part that holds the differential and drive gears. with an 8 or 9 inch rear end the carrier is removable from the housing. it is variously called a pumpkin, drop out carrier, chunk, etc. it was designed so that you dont have to pull the entire rear end from the car to swap gears.
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Route--66--
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Re: 7.25" Differential Rebuild

Post #12 by Route--66-- » Thu Aug 29, 2013 4:36 pm

ahhh. got ya!
Cheers R
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #13 by Route--66-- » Wed Sep 04, 2013 12:55 pm

Hi
A few questions as parts are now on their way across the pond to me!
Thanks in advance

Have ordered NOS pinion and side gears for the inside of the diff.
Also have ordered the rebuild kit which includes bearings, seals and the likes of crush sleeve.
Am thinking of changing the wheel bearings too - not sure if I need to - I think I have about a millimeter of play in and out - 1. should there be any play at all laterally in my bearings?

2. If I do need to change 'em which of these are the correct bearings to order?? as it list s them all as correct for my car but they quote different sizes??;
http://www.rockauto.com/catalog/moreinfo.php?pk=1118808&cc=1333370
http://www.rockauto.com/catalog/moreinfo.php?pk=221853&cc=1333370
http://www.rockauto.com/catalog/moreinfo.php?pk=1842386&cc=1333370

3. is it really important to order the 2 axle gaskets that fit by the backplate (as they are real expensive to get with shipping) or will rtv do the job

Also have found somewhere that will do the work for about $250 so for that money am not going to even consider trying to do it myself!

One thing I wasn't understanding was that rbohm you mentioned "removable carrier ... was designed so that you dont have to pull the entire rear end from the car to swap gears." .. am being a bit thick I think - surely once driveshafts and bearing caps are off it's possible to remove diff and pinion without removing the axle.?? .. am sure I'm misunderstanding but thought I'd ask!

p.s. it's mad money to get parts over to this country - diff rebuild kit from rockauto was £111 but with shipping and import duty cost me £196!!! (so that's $133 just to get the part to me!)

4. am after a nos (or perfect condition) 2.83 ring and pinion just in case anyone knows of one. If I got a 3.2 does it make a massive amount of difference to the gearing? (I have a C4 Cruise-o-matic) .. from the figures that comes out at an engine revving 13% faster to achieve the same road-speed .. .. maybe it wouldn't be toooo bad ..?

THANKS - really appreciate your time and help
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #14 by bubba22349 » Wed Sep 04, 2013 4:00 pm

1. There should be no noticeable play in the axel bearings if it were me I would likely replace them while its already apart. Though since its not that big of job to pull them you could also wait and replace them sometime in the future, your call.

2. Those all look to be the same bearing numbers just differant brands of them, the correct "part number RWF 34-R" so your choice as to which to use. Those bearings were used on many brands of cars, Have you tried to see if they interchange to bearings you might have locally available?

3. If your axel gaskets are still in one piece you could reuse them again with a little silicone or you could get some gasket paper and with a little time cut out a new set.

4. On the 2.83 to 3.20 you will loose a little fuel economy with a bit more engine noise and wear at hi way speeds,on the plus side you gain a little performance or speed on the take off from a stop.

You can do the rebuild in the car or pull it out. Too bad they can't send all the items in one shipment or would that even save you anything? Good luck
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: 7.25" Differential Rebuild

Post #15 by Route--66-- » Wed Sep 04, 2013 5:02 pm

brill, thanks bubba really useful :thumbup:

Yeh I'll 're-check' the bearings and maybe get some new while they're off .. although they don't make any noise so should be ok ..

yeh the thing with all those bearings is they quoted different dimensions .. thanks loads for the part number though, very useful

Cheers!!!
will update thread for others that come after doing the same thing :thumbup:
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #16 by bubba22349 » Wed Sep 04, 2013 8:52 pm

yeh the thing with all those bearings is they quoted different dimensions .. thanks loads for the part number though, very useful


Yeah is probably a just a typo on the listings, check the below dimensions I think they are accurate. what you will find with most bearings no matter what brand is the back number is usually the same so if you can find a cross reference book you should be able to find them or convert to other numbering systems used.

Some of the many brands that made these RWF34R bearings

Timken RWF34R
L&S Bearing RWF34R
NAPA RWF34R
Federal-Mogul Bearings & Bower / BCA RWF34R
NATIONAL RWF34R
SKF RWF34R
KML RWF34R
FK Bearing Group RWF34R
ABC RWF34R

Ford Mustang 7.25 Rear Axle Bearing measurements
Inner Diameter: 1.3386 in / 34 mm
Outer Diameter: 2.6772 in / 68 mm
Width: 0.9449 in / 24 mm

Fits Ford, Mercury, GM, Dodge, Plymouth, also were used on Trucks and Trailers, I would not be surprised if they weren't maybe used on many English and European models too.
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: 7.25" Differential Rebuild

Post #17 by Route--66-- » Thu Sep 05, 2013 3:40 am

TOTALLY excellent ! .. thanks so much for that - very useful
Cheers! :)
D
---- 1965 Mustang 200ci ----
For pics see http://www.applepiecar.co.uk

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Re: 7.25" Differential Rebuild

Post #18 by xctasy » Thu Sep 21, 2017 1:51 am

http://www.fordmuscleforums.com/mustang ... r-end.html


If you look around, the 7-1/4" axle has a 2.83 to 3.20 to 4.00 crown wheel and pinion for it, and a limited slip diff Equa Lok version.

Mike from Classic in lines disussed it many years ago.
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Re: 7.25" Differential Rebuild

Post #19 by Humpbackshooter » Thu Sep 21, 2017 11:41 am

:beer: :beer: to bubba & xctasy


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