Differential Pinion Gear Bearing Preload

I used a small plastic bucket filled with nuts and a string wrapped around the double sided bearing. Tighten until I get the inch-lbs requirement for gravity to drag the bucket down.


Joe K
 
Turn up a pulley or drum 2 inch in diameter then make an attachement to connect it to the pinion spine.
Wrap a length of nylon cord around it ,then pull it using a spring ballance reading in pounds , this will,read out the inch pound when pulling , easy
Lawrie
 
i just set the pre load by feal, like you adjust a front bering,no trouble, its been 10 years
 
Have done them by feel as I couldn’t figure the other way but did make a ring spacer to go between bearings for a bit of strength,,,made a starter ring and gradually machined until good preload achieved,,it’s trial and trial but diff has done many trouble free miles since ,,,,
 
updraught said:
Is this any good?

"Another preload simplifier is for the pinion itself: Put the assembly in a large bench vise, pinion pointed down clamped in the vise. Spin the banjo with both hands as fast and hard as you can. The correct preload will allow no more than one full revolution of the banjo."
https://fordbarn.com/forum/showthread.php?t=113792
Click to expand...

While I like this from the standpoint of empirical engineering, I can also see that it would be quite easy to accept an overly tight preload if the only criterion is “no more than one revolution of the banjo”. I’d hate to rely upon this without a lot of experience comparing banjo spin with actual torque measurement.

These days low range deflection beam torque wrenches are available for around $25. Cheap assurance for doing it right.
 
alexiskai said:
Beam type will work better than click type for this application.
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I agree. The click-type that old31 suggests has 20 in-lb (the torque spec for pinion preload) as its lower limit. I'm not a fan of using click-type torque wrenches at the outer limits of their ranges, I prefer to target say 20%-80% of full scale. I was thinking of beam-type like alexiskai suggests, like this one also available from the river store.
 
I use an old dial type torque wrench. It works on the same principle as the deflecting beam.

I'm not sure why they had such a high initial bearing preload on the early stub shaft set ups. Too much preload can brinell the tapered rollers. They need to have a good preload but it only needs enough to give the bearings extra life before losing enough material to get loose.

CAUTION: For those that set up a pinion bearing stack with USED bearings, don't set them to the initial specs. Just set them to lower marginal setting say low side minus 4 inch pounds or so. Setting them too tight will rapidly wear the rollers which are already worn to some extent. Just make sure they have some drag on them but not too much.
 
alexiskai said:
A shocking revelation. Next you’ll be telling me they’re hard to find.
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They turn up on eBay pretty often. There are two there now, one with the spring and one without. They were also made by Manzel so you can find them under that name as they took over Ford dealer tool production after KRW went away.
 
Jim/GA said:
Bob, would it be possible for you to post scans of those pages here so that we can read the entire procedure in context?

It is not clear to me where the in-lbs of torque you are quoting are to be applied. If there are some drawings in the Bulletins that show this, it may help. Thanks!
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Here are clear copies of SB 142 and 207


Jim try this.

On my machine when I click on these files they are stored in the downloads directory in the main directory.

You must go to downloads directory and click on the correct file to see clear PDF of the file.

OK I downloaded the correct SB 207 file
 

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Detail of p. 207
 

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