U joints- determine what to buy

[MooseStang]

And did I also read that the pinion is a separate section? Would rebuilding it, bearings, seals (and not regear) be another less expensive option?

 

[Don C]

With the pinion bearings being that bad there is likely a lot of metal in the gear oil and has likely also damaged the carrier bearings and possibly the gears.

To answer your question, yes the pinion bearing retainer is a separate section and can be removed from the carrier, and the pinion bearings and seal replaced, without removing the carrier.

 

[Bentworker]

Yes and no.

I am trying to figure out an elegant way to write this, but it will probably come out as one big blob.

Pinion depth and backlash control pattern.  Pinion depth is set by altering the thickness of the shims between pinion support and the third member.   Backlash is set by moving the carrier which the ring gear is bolted to left-right.  On a Ford 9” there are large spanner nuts to accomplish this.
 

The pinion is supported by two opposing tapered roller bearings.  There is a crush sleeve between the two inner races of the opposing roller bearings.   The pinion bearing preload and how much the crush sleeve is deformed is controlled by how tight the pinion nut is.

The risk of pulling the pinion support out and replacing the bearings in it alone is that you can’t be certain that your pinion depth / pattern / backlash is correct.  You have to pull the entire 3rd member to confirm correct setup.  On top of that if your pinion bearings are toast there is a good chance your carrier bearings are not much better.

It takes a few specialized tools to set one up correctly.  If that is something you want to tackle I can walk you through it.  You need a 0-30 inch pound dial or beam type torque wrench, clamshell style bearing puller and a hydraulic press.

 

[MooseStang]

Special tools that I don't have. So I'm looking at a local rebuild , or ordering a 3rd online.  Thanks everyone for your input,  I'll start the hunt for local rebuild prices and go from there. 

 

[rackerm]

Special tools that I don't have. So I'm looking at a local rebuild , or ordering a 3rd online.  Thanks everyone for your input,  I'll start the hunt for local rebuild prices and go from there. 

Where are you located. If near southern New Jersey, Alan at Ford 8 and 9 inch is the man! at  https://8and9inchfordrears.com/

I pulled a couple of driveshafts, wholerear axles or center sections with the car on ramps and jack stands. Just put in a new driveshaft in last week in my garage that way.



Alan's work below...

 

[MooseStang]

Thats a bit far, I'm just north of Houston. 

 

[Bentworker]

You might call this outfit and see if they have a suggestion for you.  They built up my FMX for me years ago and are in central Texas.

https://broaderperformance.com/

 

[c9zx]

This place is usually a bit cheaper than most if you want a complete new center section. https://www.quickperformance.com/Ford-9-Complete-Center-Section-Third-Member_p_36.html

Given that much movement you don't know the condition of other components, ring and pinion gears, bearings, side gears, etc.. If it is a Traction-Lok carrier there may be other bits needing to be changed.

If it is an open differential now would be the time to upgrade to a locking carrier. If you do change back to 3.25 gears, expect a modest decrease in acceleration. Depending what is damaged, and any upgrades, it could be as little as $450 or as much as $900 with upgrades. I'd try to find a local shop with a good reputation with local gear heads. Have them look at it and get an estimate to repair. That should help you make a decision on wether or not to buy a whole new center section. I hope the repair goes well. Chuck

 

[MooseStang]

I did get two estimates today for a gear ratio change rebuild.  Both quoted me $2k ~ $2.5k.   A third call to a Mustang only shop was about the same, but he also told me that they used to buy complete third members but had consistently run  into quality issues.  They now send them out to a local shop for rebuilds.  He gave me their name, I'll call them on Monday.  But, it's sounding more like I'll be ordering online.

 

[MooseStang]

Changing my u joints before I get my 3rd member back this week.  Measurements are matching up.  The rear joint caps are different, 2 are inside and 2 are outside, 1-1/16 and 1-1/8.

The bolts feel like their big enough the handle the 1-1/8 size.   My question is, do I need bolts sized for the smaller caps?  Or is 1/16 going to make any difference?

Also, does it even matter whether the two smaller caps have the inside clip groove or not?

 

[Hemikiller]

The caps have to match the yokes. IIRC, the 1 1/8" caps go into the pinion yoke, the 1 1/16" are on the driveshaft itself. 71-73s don't use the inside snap ring, that's just for part commonality with other applications. 

 

[71ProjectJunk]

Ford used two different size driveshafts on the 4 speed cars, depending upon rear gears. 3.25 cars were supposed to get the 1310 joint and 3.50 cars the 1330, but there have been variances in what actually went out the door. The NPD listing leaves out the 3.25/3.50 gear differences on the 351 applications. You car *should* take the -6 and -7 joint.

The only error I see in the NPD chart is the -7 u-joint should have a 1 1/16" and a 1 1/8" cap diameter.

Lots of things get swapped over the years so best to pull the shaft and measure.

E and F are the 3.25 joints, G and H are 3.50

View attachment 54238

Just took out my factory 9" center section and I can tell you that my car, which is a 1971 M-Code 4 Speed car with 3.25 open diff, it definitely uses the 1310 long yoke. I am in a pickle now as I ordered a third member from Quick Performance and told them that I needed a 3.50 trac-lock 3rd member with the correct yoke for a 71 Mustang Mach 1 M-Code car, they said no problem, they knew exactly what I needed. Well, as you can guess they sent me a third member with a 1330 yoke... So, now I have to swap yokes. Thankfully Quick Performance uses a solid spacer and shims, and not the crush sleeves on their pinions, so it should be a straightforward swap. I am sure it will still be a pain as the pinion nut needs to be torqued to 200 FT/LBS, and removing 2 yokes will be no easy task...

 

[71ProjectJunk]

Just pulled the driveshaft out and the U-joints. I got one incorrect U-joint from Napa. Hopefully this info will help someone else with getting the correct parts:
This is what is on my: 1971 Mustang Mach 1 4 speed car with 3.25 open diff
Pinion Yoke: Long 1310
Rear u-joint: 1 1/8" caps on the pinion side, 1 1/16" on the driveshaft side, 3 1/4" wide
Front u-joint: both caps are 1 1/16", and 3 1/4" wide.