9 in ford rearend (trying to see what i have )

[305chevy c-10]

picked this rearend up from a freind for 30 bucks complete with 3rd member . i think i have 28 spl but some site say 3 holes in center of axle is 31 and 28 have square slot .the pinoin support has c5aw  -4668a  on it .when i tore it down it has c4aw - 4025a on the inside of the 3rd member .the ring gear has ford  c2aw 4210.no sure if this is ring and pinion teeth count. i do know this is an open carrier .i do plan on shortening this rearend

[Fairlane514]

Count the splines on the axle and you will know if its 28 or 31.  The case is a 1964, the pinion support is 1965, the ring gear is 1962.

Ford numbers start wit the letter which denotes the decade of manufacture. "C" is the decade of 1960 and the next number is the actual year.  a "B" would be 1950, "D" 1970 etc...

Count the teeth on the ring gear and the pinion and divide the numbers, it will give you the gear ratio.

[305chevy c-10]

i counted 28 spl ,but some pics of 28 i have seen axle was very tapered so u could not shorten them .the end with spl was thick then it tapered down maybe 13inches or so then went back to same size as spl end .these may have been the 50's axles .i know i have the big bearing but its not the (torino style 3 -9/16 x 2 )mine are 3-1/2 x 2-3/8 . i was told ford explorer disc brakes bolt to big bearing housing ends but which one .

[HAULIN IT]

That appears to be a '73-'79 truck or van rear. It will measure 65" total with both axles being the same length...just under 32". The 4210 is on all oem 9" Ford rings, it's the base part number. Count the teeth on the ring & divide by the teeth on the pinion for the gear ratio. The part numbers on the case, pinion support, ect. do not relate to the year of your parts. It just means it was the first year that part was cast. When a change was made to a part, it would get the new year's date. Much like tail lights of older vehicles.
The tapered axle shafts were all done by the mid '60's. Yours are just the regular stepped items that can be shortened, however there are some things that can get you fouled up. 1) You have to take either less than 5/8" off of the splines or remove at least 4" & then re-spline. You can't re-spline the "scribble" area just past the original splines...it's smaller in O.D. than the shaft. 2) The pinion on that rear is 4" off-set to the Right...less than ideal for most vehicles. This can be corrected if your wanting to go narrow enough. 3) Wheel bolt pattern is & the drum register are HUGE & does not match the Explorer.
 The "Torino" wording is something that has been used for years (again, first to use this "new" bolt backing plate bolt pattern) & really means nothing. What counts is the size of the backing plate bolts. The earlier ones have 1/2" bolts (uses a 3/4" socket to remove) & the later (about '78) use a 3/8" bolt (uses a 9/16" socket to remove. The 3/8" ones match the Explorer caliper/backing plate.
Tell me what you want to end up with & I'll give you my opinion on the best plan, parts, ect. to get you there. Hope this Helps! Lorne         

[305chevy c-10]

wow thanks thats alot of info . i came up with same numbers axles 31-7/8  equal length .3.00 gear 39/13 .did not catch the 4" offset pinion.are the one with different length axles pinion centered .or would a different housing be easier than narrowing it alot to correct it .is it possible to shorten it 8 inches overall and still keep leaf springs in stock location.or is it to much so i will need new axles ..the plan(1) is to cut wheel wells back to frame or just 3 inches  so a 315 or 325 tire will sit snug under fender and not tounch the inside or outside of rear fender.(2)
get trac lok with 3.70 gear(3). disc brake conversion kit  **Ford 9" old large bearing rear disc brake conversion. You will receive the following items.$350

2 New 11" drilled and slotted rotors with an anodized finish.the rotors have A 5 on 4.5" and 4.75" Bolt Patterns
2 New calipers with built in emergency brake.
2 New emergency brake cables
1 New center emergency brake cable
2 New rubber hoses
Complete mounting hardware. (caliper brackets, bolts, spacers, ect.
 
(4)i want to put my shocks on rear of axle like urs was .

[HAULIN IT]

wow thanks thats alot of info . i came up with same numbers axles 31-7/8. did not catch the 4" offset pinion.are the one with different length axles pinion centered .or would a different housing be easier than narrowing it alot to correct it .is it possible to shorten it 8 inches overall and still keep leaf springs in stock location.or is it to much so i will need new axles ..the plan(1) is to cut wheel wells back to frame or just 3 inches  so a 315 or 325 tire will sit snug under fender and not tounch the inside or outside of rear fender.(2)i want to put my shocks on rear of axle like urs was .

To answer/comment in order. The pinion off-set is often misunderstood, particularly by "GM" guys because they are used to seeing 2 axles the same length, but is rather simple. The way it works is this: It's all figured from some math from 4". A centered pinion rear will have axles 4" different. One like yours with the same axles has a pinion 4" off-set. Any math works out...3" different, 1" off-set, ect.
The pinion off-set is one thing that can be a deal breaker particularly in a car...a guy gets 4" cut off each axle & each end of the housing to get the total width down to a usable number, puts it in to find the driveshaft hitting the Right muffler, trans. tunnel, ect. Sure it will work in a truck, but it's less than ideal.
In your case, a better plan would be to take 4" off of the Left axle & housing to make the pinion centered & give you a final measurement of 61" (Mine is 59"-60" from what I remember). The springs do not need moved fit a tire like your wanting. With the wheelwell moved back to be flush with the edge of the spring, you will end up with PLENTY of clearance (mine has about 1 1/4" on each side of the tire with a 325 50 Et Street radial) with the right combination of axle width & wheel backspace.
If you want to mount the shocks like mine you will have to leave the springs on the stock hangers (widthwise), I have 3/8" between the frame & the tube of the shock, also 3/8" between the shock & the spring. 

As to what is ideal for what you are wanting...I'm not sure. You still will have the wrong wheel bolt patern & brake register. You could get around that if you can find a pair of '80-'84 F100 axles (they have the 4 1/2" wheel bolt pattern to match those brakes or the Explorer ones), but they are 31 spline. One other low-buck option (if you can find them) is '75-'77 Lincoln axles. They have the same wheel bolt pattern as our trucks, have a 1" off-set pinion, 28 spline & can be trimmed to end up with a 63 1/2" rear. I have built a couple rears for '60's-'70's GM trucks using these axles. I wouldn't overlook the "bubble era" Impala rear discs either...they have the same wheel bolt pattern as our trucks also.
The best & easiest way to go is get custom made axles for your application...but it's also the most costly.
I've posted lots of pictures over the years. You can look through my post history. If you have any other questions, just ask! Lorne

[305chevy c-10]

ok are u saying the 61 is axle flange to axle flange ,or backing plate to backing plate .now i understand the 4" offset .i called junk yard where i do business at and he said $100 for explorer brakes ( gonna get rotors re drilled ).seen custom axles with 8" of spline and 5 x 5 bolt pattern with explorer register for sale on ebay  .

[HAULIN IT]

Yes 61" total, wheel flange to wheel flange is what you would end up with by doing just the left side to improve the pinion centerline. You could "squeeze" the center airgap between the 2 axles a bit & take about 1/2" off of the Right axle which would bring your total just a tick over 60" & have a 1/2" pinion off-set. The total number needed solely depends on the wheel backspace you end up using. The width of mine is narrower that really needed on the out board side & also only have a 4" backspace (I had the wheels YEARS before the truck). I built the rear around the space between the 2 wheel/tire assemblies in place...which is what I would suggest you do. A 5" backspace 10" wheel with a 61" rear should be fitting pretty nice with the wheel tubs slid back to the outside of the spring.
 With a 325 50 Mickey drag radial (about a 11 1/2" section width) mine has about an 1 1/4" both on the inside & outside...honestly twice what is needed, so if you end up with a "fat" 315-325...you'll still have plenty of room.

The brake plan sounds ok (I personally would work with the Impala stuff if staying with 5 x 5" bolt pattern). You may need to slot the holes slightly in the bearing flange for the Explorer parts to fit if you have the "wrong" spacing like you mentioned, but no big deal.
 One word of caution: Keep an eye on the caliper to spring distance when coming up with your housing width...You need more distance here than on a drum brake set-up. As you start to narrow the housing, the distance & placement of the caliper mounting bolts need to be kept track of.

Here's a couple pictures of the clearance I've got. Hope this helps, Lorne
 
 

[305chevy c-10]

hey thanks HAULININ IT,you were very helpful .the guy i got the rearend from told me all 9' rears he has seen has that offset but he corrects it by cutting 4' off left when he installs  it like u said .done some more research on my axle and found out why it has the 3 hole on hub like 31 spline axles .after about 1970 all 9" rears came with 31 spline axles but some were turned down to fit 28 spline carriers .the area with scribble marks is to fit inside carrier .if u go past this area they can be respline to 31 .as for my app im gonna buy some used OE 31 spline big bearing axles  with new style retainers (2 x 3.562) to fit explorer brakes.a guy on ebay hs them for about $120 shipped.new late model   housing ends $80.i think the 61" will get me where i want to be .i think that narrower than stock 10 bolt .seems like that the size backing to backing plate on 10 bolts .i thought about the other disc brake setups but 8.8's are very easy to get around here unlike the chevy stuff

[HAULIN IT]

hey thanks HAULININ IT,you were very helpful .the guy i got the rearend from told me all 9' rears he has seen has that offset but he corrects it by cutting 4' off left when he installs  it like u said . housing ends $80.i think the 61" will get me where i want to be .i think that narrower than stock 10 bolt .

Glad to help, All of the truck & full size van housings have the 4" off-set. It appears it was done originally to put the driveshaft lined up with the engine in the earlier trucks to help clear the steering shaft. Later they used it also to clear the inside the frame gas tank. The cars have much less off-set, typically 1"-2".
The original total width of your 10 bolt is right around 65" .

Be sure to take the time to test fit the brakes for caliper bolt, hose & E-brake cable fitment before the ends are welded on...sometimes a 1/4" is the difference between "Right & Ahh, $hit!"
 The top picture is the Crown Vic set-up (VERY similar to the Explorer) in my truck. The bottom is a Right Stuff kit (in an early Mustang) like you posted earlier...notice where the brake hose & Blue punch is compared to the spring! There is way more clearance there then it may look in the picture, but it would have been a no-go if rotated downward a few degrees.
 

One other thing to keep in mind with the Explorer brakes is that you need a spacer between the axle bearing & the retainer plate to make up for the increased thickness of the backing plate/caliper mount.
I make them out of a slice of old bearing race. Good Luck with your project, Lorne

[305chevy c-10]

will i still need the spacer if the axles have to 2 1/2 brake offset or is the space only because of the backing plate thickness.i'm gonna give moeser a call tom to see if is cheaper to just buy axles ready for this setup with my bolt pattern in it or send them mine and let them put spacer,bearings and etc on them and drill them for 5x5 and turn register down to 2.80.heres another question .can i use the stock axle retainer(torino style) thats  on the axle or will i have to use the gold looking retainers that just slip on the axle .im trying to see if i realy need to buy this other set of 31 spline OE axles with torino style retainers on them. or use my 28's that came with the housing and put on new gold retainers .28 and 31 spline posi unit cost the same so im undecided about axle spline .here a aftermarket set im thinking of if moeser is too pricey .