ConcoursMustang Forums
Restoring - General discussions that span across many different groups of years and models => Drivetrain => Topic started by: 68 S Code on June 12, 2011, 03:42:51 PM
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Per 68 Osborn assembly manual it states that assembly and torquing of rear universal joint u-bolts is to be done with 300 lbs (300 ft lbs?) of pressure on the cups with a clamp. See page 35. Do you guys typically do it this way
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Never torqued them
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after making sure the cups are firmly seated i use a drop of loctite on the u-bolt threads. then just 'good & tight' in a crisscross pattern........never had a problem.
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Thanks guys. I'm sure my torque wrench doesn't even go to 300.
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Probably a mis-print. I could believe 300 in-pounds.
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The u-bolts would no-doubt shear at 300 ft/lbs! Lug nuts on big trucks are only torqued at about 150 ft/lbs.
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I thought that as well about it being possibly inch pounds versus ft lbs. But if that was the case then they probably would have just said 25 ft pounds. Either way it's ambiguous. This wasn't a torque figure for the u bolts but a pressure to be applied to squeeze the two cups with a clamp prior to torquing the u bolts. The illustration on page 35 shows a clamp on thr cups. I guess they wanted them to be seated similar to the way the 2 other cups are with the snap rings,
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The rear yoke usually has a shoulder on each side where the cups fit in. Can just squeeze by hand to get them into the right position.
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Thanks charles. Here is a pic of the driveshaft. Not as good as some of the ones I've seen on this site but its for a driver. Can't even count the amount of time I've spent researching and painting this one up.
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Thanks charles. Here is a pic of the driveshaft. Not as good as some of the ones I've seen on this site but its for a driver. Can't even count the amount of time I've spent researching and painting this one up.
Just a a note - the yokes were painted before they were welded to the tube (to help the worker making the drivelines identify the yokes quickly) so no over spray on the tube an no paint on the weld. Of course originally the heat of the welding would have damaged the paint directly nearby
Looks good
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The yellow overspray looked to be an alignment mark similar to the mark on the differential yoke. It is a different (brighter) shade of yellow. The base color of the driveshaft yoke is a yellow/orange. It is difficult to differentiate in the pic but in person easier to see. As light as the bright yellow mark was in person I assumed it was sprayed on after yoke was welded so I let it overspray onto the shaft as shown. I did add a brownish gray band to simulate the heat discoloration due to welding after I took the pic. Jeff thanks for the comment. By the way the front driveshaft yoke looks red in the photo but it is really a pinkish/red.
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The 300 pounds of pressure that the Osborne manual is referring to is NOTTTT 300 foot pounds or inch pounds on the four nuts! It MEANS that the clamping pressure of the U-bolts onto the cup is 300 pounds.
Just shooting from the hip, I would say that 40 to 50 inch pounds on two nuts with fine threads would create 300 pounds of clamp force on each cup???
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I appolpgize for making the post confusing. The con fusion stems from the post mentioning u bolts and this cup pressure. This 300 pounds is not a torque on the u- bolts. It is a pressurewhich a clamp exerts onto the two cups as you torque the u bolts per spec. The illustration shows what appears to be a clamp end at each cup. The ambiguous part is 300 pounds. Foot, inch ???? I only bought it up as it seemed important enough at the time for the engineers to call it out on a seperate drwg. I've never installed u bolts while applying this pressure and from what others have said in responding to this post either have they. Figuring that the car will only be occasionally driven, probably not flogged, I'm not taking any undo risk by skipping the clamp proceedure?
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If you bench press 600 pounds on a weight machine, you are putting 300 pounds of pressure on each handle.
Not 300 PSI, Not 300 ft Lbs, Not 300 in Lbs.
Just plain old pounds of pressure.
That's what the engineers intended. Just plain old 300 pounds of force on the cup, pushing it down into its' receptacle in the yoke.
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So put a clamp on it and squeeze the cups a touch (not cranking down as hard as you can) and then tighten the u-bolts to spec. I wonder if they had a special clamp for this with a gauge on it at the factory? Thanks
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Building 2 million+??? I'll bet they had a special fixture that did it!
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The only squeezing required is before seating the cups into the pinion, which can usually be done by hand. Once the u-joint cups are seated in the pinion, they don't need to be held when tightening the u-bolts... other than just making sure everything stays straight.
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Got it. Thanks to everyone who helped to clear this up for a newbie.
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I finished the install of the driveshaft and I saw that the small tabs in the yoke keep the cups seated. Once you get the cups past the tab you can toque the nuts on the u-bolt. Tried using the clamp but it just got in the way.