9 inch info needed 31 spline

[83slimer]

Hi Guy's

I score a deal on a complete 1970 f 100 rear end , net says same width as our cars. Its 31 spline limited slip. The guy even had records of its maintenance. I brushed the undercoat on one spot and its painted white lol. Soooo... it 5.5x5 my unilug rims only go 5x5. I'm either going to get new rims or see if a machine shop can re drill the axle shafts for 4.5 anyone ever done this? but then Id have to do something about the brakes as they are 11 inch vs 10 on ours Its 3.54 ratio . I need to cut off the spring perches and shock bracket and weld on some new perches. Its a big bearing I assume and the axle tube is the same diameter doesn't taper. Good deal for 245 Canadian. Also the yoke I beleave is 1350 or 1330. If I put my yoke on it do I have to replace the crush sleeve? whats involved here? I haven't measured yet but are all 9 inch axles centered on the yoke?

 

[Bentworker]

It will be WAY too wide.

But your could purchase 31 spline axles for your housing and run that third member in it.

 

[83slimer]

It will be WAY too wide.

But your could purchase 31 spline axles for your housing and run that third member in it.

71-73 61.25

70 f 100 61.25

So same width,

 

[73pony]

I think it is the same width as well but... I think in the long run it would be easier and cheaper to swap the third member and get new axels to fit. Especially given the different bolt pattern and other brake size issues.

 

[83slimer]

I think it is the same width as well but... I think in the long run it would be easier and cheaper to swap the third member and get new axels to fit. Especially given the different bolt pattern and other brake size issues.

Yes thanks, I do like the massive 11 inch drums though , I'm pulling the axles out of it tonight because back in 70 a 28 spline can look just like a 31 if your going by the look of the end of the axle. If it turns out to be a 28 i can just swap that 3rd member in my car, and possible change the yoke as they are different. I'm planning on new U.S mags u101 slot rims just like i already have, If I use the axle the way it is I'll just order 2 5x5.5 rear 10 inch wide rims with the right offset. Planning on running staggered either way.

 

[Bentworker]

Doh! I was wrong.

 

[Carolina_Mountain_Mustangs]

Using the current axles will mean you need two different spare wheel sizes or a unilug design that some aluminum wheels had. The picture is of a regular 28 spline 9" in my vert. Had to replace broken stud. I don't think there would be room to drill the mustang bolt pattern in the truck axle due to the three access holes in the axle to get to the 4 bolts on the axle flange and maintain balance. The boss on the axle might also have a larger diameter than mustang, Mercury did I know. That is what carries the weight of the car and centers the wheel not the lug bolts.

Always look under the trucks and vans in 60's and up until they went to Spicer type. I got a 9" 28 spline N case out of 1969 ford van that everything fits the mustang same yoke even. The housing on a van is offset to one side so it is of no use unless you want to make a narrowed housing. These go to the crusher and most never look at the center section.

If you have a friend with a lathe, mill and a dividing head you can cut the axles off and re-cut the splines on long axles that are not tapered, big bearing axles I think. You can get a roll pin dimension across the splines and cut new the same.

If you are going to punish the rear with big HP paint a stripe on the axle and then you can tell if they are twisting and about to break.

 

[bkdunha]

++ 1 on the other comments. I would swap out the third member and get new axles. All of the changes required to that axle just to maintain an 11 drum sound challenging.

 

[71mach351]

I'm building a 53 f100. It came with a 1970 truck rear. I found that it had 28 spline axles. The tag on the 9" decoded to a 3.50 open with a 8.75 ring gear, not a 9". Is the tag still on the center section?

 

[83slimer]

I'm building a 53 f100. It came with a 1970 truck rear. I found that it had 28 spline axles. The tag on the 9" decoded to a 3.50 open with a 8.75 ring gear, not a 9". Is the tag still on the center section?

No was missing. I took it apart last night and its 28 Spline !!! Now I can swap it in my mustang housing, the gears looked very nice, 3.50 ratio and limited slip. 98% sure its a direct swap in. My gears were 2.79 or something like that so 3.50 should be real nice! How can I tell if it 8 3/4 vs 9?

 

[73pony]

Sweet! I would be sure to replace the axel bearings and seals while you have the axels out. As for the yoke. If it is the same length yoke as what you have you can use the existing and just get the correct U-Joint. 1310 to 1330 or 1350 u-joints are easily accessible.

 

[Don C]

You can always install 11" brakes on you car, either with original Ford parts or a kit:

http://www.mustangandfords.com/how-to/wheels-tires/mump-0704-drum-brake-installation/

 

[Jeff73Mach1]

1350 U-joint is much stronger. If it were me I'd have my driveshaft reworked to use 1350 Ujoints on both ends rather than replacing the pinion yoke. About 100.00 worth of labor, a slip yoke and the weld yokes for each end. You'll then have a very durable driveline for about an extra 300 bucks

 

[83slimer]

1350 U-joint is much stronger. If it were me I'd have my driveshaft reworked to use 1350 Ujoints on both ends rather than replacing the pinion yoke. About 100.00 worth of labor, a slip yoke and the weld yokes for each end. You'll then have a very durable driveline for about an extra 300 bucks

We are pretty limited where I live for drive shaft shops, but yes keeping the f100 yoke 1330 or 1350 and upgrading my drive shaft would make it that much more durable. I looked into it more and it looks like I have the equa lock limited slip, not one of the stronger ones but for the price i got it all im just going to leave it the way it is and replace it when it fails. The guy I bought it all from said it still worked fine. I already have new axle bearings and seals on the mustang rear so should be good to go. Just waiting on the 9 inch 3rd member seal and new pinion seal if I end up swapping yokes.

THe difference in yoke size is 1 inch shorter on the f100 one. Think I have enough slip on my c6 yoke to use the same drive shaft? It would make the slip youke stick out 1 inch more than stock? seems to be plenty of shaft still inside the tranny.

 

[Jeff73Mach1]

No, 1 inch too short is too much, it affects spline engagement and reduces the strength considerably. Actual driveshaft movement under full suspension travel is generally less than 1/2 inch so while it wouldn't fall out, you could more easily twist the splines. If you change the yoke, you will need to do some measuring and verufy that backlash has not been altered. If it used a solid spacer, you are in good shape, if it used a crush sleeve it is more work.

 

[Bentworker]

If you do decide to swap yokes read this.

The tightness of the nut that holds the yoke on controlls pinion bearing preload. Stock 9" axles have a crush sleeve between the inner races of the two opposing tapered roller bearings on the pinion. Before you take the yoke off of the third member that you are going to use get an inch pound dial type torque wrench and record the amount of force it takes to turn the pinion. After that remove the nut, use a 2 jaw puller to remove the yoke. R&R the pinion seal, install the new yoke with some sealant on the splines. Tighten the pinion nut in small increments, checking preload with the torque wrench often. Tighten the pinion nut until the force needed to turn the pinion is 1-2 inch pounds more than what it took before you took it apart.

If you go too far you need to pull it back apart, remove the entire pinion assembly from the third member and install a new crush sleeve... and try again.

 

[83slimer]

If you do decide to swap yokes read this.

The tightness of the nut that holds the yoke on controlls pinion bearing preload. Stock 9" axles have a crush sleeve between the inner races of the two opposing tapered roller bearings on the pinion. Before you take the yoke off of the third member that you are going to use get an inch pound dial type torque wrench and record the amount of force it takes to turn the pinion. After that remove the nut, use a 2 jaw puller to remove the yoke. R&R the pinion seal, install the new yoke with some sealant on the splines. Tighten the pinion nut in small increments, checking preload with the torque wrench often. Tighten the pinion nut until the force needed to turn the pinion is 1-2 inch pounds more than what it took before you took it apart.

If you go too far you need to pull it back apart, remove the entire pinion assembly from the third member and install a new crush sleeve... and try again.

I've been doing some reading on this, your method sounds good, just dont have a inch pound dial , The method I was going to use is mark the shaft and nut , count the turns to take it off and re install the exact same amount of nut turns. Some say tighten the nut another 1/8 of a turn some do not. Might be worth investing in a dial indicator.

 

[Bentworker]

The counting turns method is poor at best, and does not work at all when you swap yokes. The distance from the end of the yoke to the nut will be different on different yokes. So tightening the pinion nut to the exact same place on the pinion will result in a different preload when using different yokes.

Just spend $50-200 for a new or used dial type inch pound torque wrench. It is the only way to ensure proper preload.

Other methods may work... or not.

Wrenches to look for...

Snap On TE6A

CDI 751LDIN.

Proto J6169F

You can buy the CDI tools ones from Zoro tools online, and they often have competitive coupons.

No matter which one you buy if you are careful you can purchase it, use it then resell it used for a small loss. Consider it a "rental" fee if you don't want to add it to your tool collection.

 

[83slimer]

The counting turns method is poor at best, and does not work at all when you swap yokes. The distance from the end of the yoke to the nut will be different on different yokes. So tightening the pinion nut to the exact same place on the pinion will result in a different preload when using different yokes.

Just spend $50-200 for a new or used dial type inch pound torque wrench. It is the only way to ensure proper preload.

Other methods may work... or not.

Wrenches to look for...

Snap On TE6A

CDI 751LDIN.

Proto J6169F

You can buy the CDI tools ones from Zoro tools online, and they often have competitive coupons.

No matter which one you buy if you are careful you can purchase it, use it then resell it used for a small loss. Consider it a "rental" fee if you don't want to add it to your tool collection.

I understand the issue if the yoke depth varies, my question is that now when i spin the yoke I fell drag but since the pinion is in the 3rd member I'm also spinning the ring gear, Am I not going to get a skewed result as the resistance felt is are the carrier bearings as well? I could take the pinion support apart but I would have to mark where the teeth contact so I put the pinion gear back in the exact same way. That way Id only be measuring the actual preload and not all the other bearing resistance in the 3rd member..