U-Joint Bolt Problem

[kcmash]

I am pretty frustrated with the details today.

I had a posi 9 inch pumpkin rebuilt for my car. I am finally putting the driveshaft in and realize that the u-joint bolts from my original 9 inch have a 1/8 inch wider bolt pattern than my original. My original pinion has 1 5/8 inch centers on the u-bolts. The pinion on the replacement pumpkin has the 1.5 inch spread.

Needless to say this is another one of those stupid details that ruined the day. Should I try to find the correct u-bolts? Where do I find them? Should I change the pinion over so I have my original ?

Please Help!!!

kcmash

 

[Don C]

There have been other discussions on the forum about u-joint sizes, there is probably one available that will work. Here's an example:

http://www.7173mustangs.com/thread-u-joint-dilemma

I would also be concerned about the length of your yoke, as different lengths were also used, causing drivelines to be the wrong length:

http://www.7173mustangs.com/thread-third-member-proper-yoke

 

[kcmash]

Thanks for the info.

I recall that this pumpkin came from a Ford Van front differential. I found the correct u bolts at o'reilly.

Kcmash

 

[OMS]

Caution, your drive shaft will have the 1 5/8 U-joint caps so just changing u-bolts won't solve your problem.

As Donc said you will need to get a conversion U joint

 

[kcmash]

Yes, I see. I realize that the new bolts fit, but the cap does not seat all the way.

So here is what I am trying to understand now. I had the differential in the car professionally rebuilt several years ago, and it has not had a mile put on it since I have been in restoration mode. I do have my original differential and pinion yolk,

1) How do I get the pinion yolk off after removing the nut? (Puller, or persuasion?)

2) Can I simply mark the nut height on the rebuilt unit in the car, remove the small pinion yolk, and install my original without having to remove the pinion carrier and re-do the crush sleeve? I thought I would find an easy answer on youtube, but no such luck.

Thanks!

kcmash

 

[kcmash]

Or is it just cheaper to go get the correct u-Joint( I think you said a conversion U-joint)

For $20 that may be the best bet. Do you know what number I should ask for?(Part number that is)

kcmash

 

[Don C]

Yes, the new u-joint would be much easier. However, before you go that route you'll need to make sure that your driveline is the right length for that yoke.

If you decide to swap pinion yokes the biggest problem you'll have is in getting the nut off the pinion, it takes a big breaker bar and something to hold the yoke to keep it from turning.

Yes, you'll have to replace the crush sleeve and you'll need a big enough torque wrench to handle it.

Because it has been sitting for several years the pinion seal is likely dried out, I would replace it, too.

 

[kcmash]

The impact wrench did a good job of removing the pinion nut on my original unit. So I did not need a breaker bar or a lot of muscle.

The driveshaft appears to be just right for the current pinion yolk on the car. I just need to know how to specify the correct ujoint for thus setup. I really don't feel like tearing into the pinion assembly.

Kcmash

 

[Carolina_Mountain_Mustangs]

For sure you want the larger dia. u-joint. Ford built my 73 Mach 1 with the small joint and after I broke 3 of them in less than 6 months they found the error and changed the yoke driveshaft and also put a 3.5 gear in to replace the 3.25 under warranty. That was with the low HP Q code in 73 so much weaker.

 

[kcmash]

Well, I want to do things right, so riddle me this Batman!

I watched a video on rebuilding the 9inch pinion assembly with a crush sleeve earlier. Without too much detail, they basically set the crush without the seal or oil slinger installed. After setting, they removed the yolk, put the oil slinger and seal in then torqued the yolk back in place.

If the last thing you do is install the seal, and pinion yolk, why do I need to go through the whole crush sleeve process again? Or should I just pull the pinion, take to a shop and say "swap these please" and assume they do it right?

kcmash

 

[mjlan]

I'm not sure how that makes sense. The crush sleeve's purpose is to distort a specified amount when placed in compression by the torque of the pinion nut. My guess is they were trying to accurately measure the drag or preload in the pinion bearings without the added drag of the seal. If they re-torqued the nut to roughly the same value, it should be close, but that isn't the Ford-specified procedure.

The above being said, I don't think doing it that way is totally wrong just provides another opportunity to make a mistake and get it wrong.

My $0.02 here is the best way to go, if it looks like your driveshaft is the right length, is to pop the u-joint out and take it to a good, old school auto parts store. They should be able to set you up with the right joint. I went through this a while ago on a Galaxie, the Mustang had a 1 1/16" dia. cap, and your new yoke needs a 1 1/8" cap. Pay attention to the yoke length as well, as there's a short and a long- the long takes a clip inside on the cap, the short sits inside of "tangs" on the yoke and gets held in place by a u-bolt...

 

[Bentworker]

Sounds like the video you watched was for setup with a crush sleeve elimination kit. If you set it up like a Dana axle with shims instead of a crush sleeve you do the setup without the seal installed since you have to put it together and take it apart several times until you get the correct length of shims between the two inner pinion bearing races to give you the desired preload. Once you achieve the correct preload you remove the yoke one last time and install the slinger, seal, and use a new pinion nut to torque it down to a fixed value.

If the video wasn't showing setup with shims it probably was showing how to incorrectly do a crush sleeve setup.

With a crush sleeve you just slap the entire assembly together and tighten the pinion nut until you have crushed the sleeve enough to give you the desired bearing preload. There is no magic torque value to apply to the pinion nut that will equate to correct bearing preload even though some manuals make that appear to be true. Differences in crush sleeve hardness, and how much drag the pinion nut has, and what assembly lube / sealants you use mean that you have to check preload with a dial type inch pound torque wrench. Don't quote me on this but I think correct preload for a 9" is 9-15" lbs of force to turn the pinion. You can pick up a quality used dial type inch pound torque wrench and be set for whatever the future tosses at you. If you also work on larger stuff (pickups) it makes sense to get one that goes to 60"lb. All you do is tighten it, then check preload... Repeat, and go in small increments to not overshoot.

Too little preload will allow things to deflect and self destruct. Too much preload will destroy the bearings. Both are bad, if you are going to swap yokes you need a dial type inch pound torque wrench to ensure that it is done correctly.

 

[Don C]

The Ford manual says that if you exceed the preload you have to start over, with a new crush sleeve, that backing off and trying to reset the preload is not acceptable, so the same would go for trying to use the same crush sleeve on a different yoke. Crush sleeves are not expensive and easy to obtain, so there's no reason to try to re-use the old one. My local NAPA store has them in stock for $4.29.

Bentworker's preload is close for used bearings, my manual says 8 to 14 inch-pounds, for new bearings is 22 to 32 inch-pounds. I assume your rebuilt carrier has all new bearings, but it depends on the caliber of the re-builder.

 

[OMS]

Go to your local NAPA store they [ at least around here ] have the best searchable database for U-joints

First as DonC said make sure the yoke lengths are the same or test fit your drive shaft.

Mark the U-joint in your drive shaft as to what end fits the shaft and what fits the pinion [ or needs the size change ] Take that to NAPA

Get the non grease-able joint and you should be OK

Grease-able joints have holes drilled for grease and that may weaken them.

 

[kcmash]

Well,

It looks like I will have to do something different here. I just bought new U joints from NAPA when I discovered the problem. It does look like the driveshaft is correct for my current setup. I have about 2 inches gap at the tyranny side yoke that could absorb rear end travel. So if I just go buy the correct custom rear u joint I will have the correct length.

If I decide to change the pinion yolk, my original measures about 2 inches longer than the one on the. car, so I will have to go with a shorter driveshaft. I guess I could use the original shift that came on my car and just put the speed yoke on it.

Maybe I can do a better job next time with painting.

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