Half Shaft U joint torque method

[Steve L.]

This is the u joint right next to the diff. with the saddle.
How do you torque it to the 16 ft lbs?
I can't get a torque wrench into it with or without universal. There is not enough room between the bolt and the diff.

This is for a 73

[Donald O.]

Re: Half Shaft U joint torque method

I use a "Crows Foot" socket. Its like an open ended wrench that attaches to the square of a ratchet or torque wrench. They are available in inches or metric and in a tubing open hex design.

DonO

[Steve L.]

Re: Half Shaft U joint torque method

Never thought of a crows foot.
But I think the center of torque application will change so the torque will need to be calculated. The effective torque arm length will be shorter.

[Ridge K.]

Re: Half Shaft U joint torque method

Steve, I would doubt that the change would be significant.
I worked at a dealership during the 1973 model year.
I never saw a mechanic put a torque wrench on, while tightening u joints. Maybe some did, but I never saw one do it.

Ridge.

[David H.]

Re: Half Shaft U joint torque method

... The effective torque arm length will be shorter.

Depends on the position of the crows foot on the wrench. (Typically, the crows foot is going to be attached in-line with the bar and pointed away from the handle.) If the crows foot is further from the handle (than a socket would be), then the lever arm is longer.

For a short crows foot, there won't be much difference. If you had a crows foot where the mouth was at the end of a couple inch bar, then you may want to recalculate.

[Joe L.]

Re: Half Shaft U joint torque method

This is the u joint right next to the diff. with the saddle.
How do you torque it to the 16 ft lbs?
I can't get a torque wrench into it with or without universal. There is not enough room between the bolt and the diff.

This is for a 73

Steve-----


I assume you're talking about an application that uses u-bolts rather than cast iron caps with hex bolts. With the latter, torquing the bolts is easy. My brother was the original owner of a 1973 with base engine and 4 speed transmission. His car had the cap type rear yoke axles.

Anyway, with the u-bolts, you torque the nuts just as Don O described, using a crow's foot wrench adapter. I wouldn't be too concerned about calculating a torque adjustment for the extra length of the crow's foot. However, the torque on these nuts is actually fairly critical (as it is on driveshaft u-bolts for some Corvette applications). Too little or too much torque can actually result in premature u-joint failure. You don't need to be "dead-on", though.

[Lynn H.]

Re: Half Shaft U joint torque method

Steve-----


I assume you're talking about an application that uses u-bolts rather than cast iron caps with hex bolts. With the latter, torquing the bolts is easy. My brother was the original owner of a 1973 with base engine and 4 speed transmission. His car had the cap type rear yoke axles.

Anyway, with the u-bolts, you torque the nuts just as Don O described, using a crow's foot wrench adapter. I wouldn't be too concerned about calculating a torque adjustment for the extra length of the crow's foot. However, the torque on these nuts is actually fairly critical (as it is on driveshaft u-bolts for some Corvette applications). Too little or too much torque can actually result in premature u-joint failure. You don't need to be "dead-on", though.

Joe,
I have owned two different base motor 73 cars (both with 3:36 posi gear sets), and both of them had the caps on the rear differential that I would only expect to see on big block cars. I have often wondered about this, and see from your post that this was something that may have been more common than I had originally thought. The cars I had were at both ends of the build sequence with VIN numbers of 05453, and 40233. Any idea why this was done on those 73 base cars?
And by the way, both of my cars were automatic transmission cars.
Lynn

[Gary R.]

Re: Half Shaft U joint torque method

my original 72 base auto also has the "hd" yokes. I believe just the SB 4 spd had the u-bolts in the early c3 run but I could be incorrect.

[Terry M.]

Re: Half Shaft U joint torque method

Gary,
During 1968-1972 (and maybe after, but I don't know) all TH400 Corvettes had the "hd" yokes. Thus i get a chuckle when folks talk about "BB: yokes. Methinks the yokes on them.

[Gary R.]

Re: Half Shaft U joint torque method

Hi Terry,
Thanks I thought that was the case as I recall.

As far as the "HD" yokes, I've heard for years they are better then the std u-bolt axles. I never bought into that too much. I like them but other parts will fail in most HP usage. I've seen the splines twist,the axles break,joints pop,posi crack,and outer axles break but haven't seen a U-Joint yoke fail at the U-bolt. This doesn't mean it can't that's for sure.

When I build a HD differential or trailing arm I use 30 spline axles that I have treated and then I finish grind them. These are indeed "HD" axles.

[Terry M.]

Re: Half Shaft U joint torque method

WOW -- You have nice parts Gary.

[Michael W.]

Re: Half Shaft U joint torque method

Joe,
I have owned two different base motor 73 cars (both with 3:36 posi gear sets), and both of them had the caps on the rear differential that I would only expect to see on big block cars. I have often wondered about this, and see from your post that this was something that may have been more common than I had originally thought. The cars I had were at both ends of the build sequence with VIN numbers of 05453, and 40233. Any idea why this was done on those 73 base cars?
And by the way, both of my cars were automatic transmission cars.
Lynn

Conversely, my base engine w/M20 and 3:36 '73 built July 5th had the expected straps on the yokes.

[Jim T.]

Re: Half Shaft U joint torque method

Joe,
I have owned two different base motor 73 cars (both with 3:36 posi gear sets), and both of them had the caps on the rear differential that I would only expect to see on big block cars. I have often wondered about this, and see from your post that this was something that may have been more common than I had originally thought. The cars I had were at both ends of the build sequence with VIN numbers of 05453, and 40233. Any idea why this was done on those 73 base cars?
And by the way, both of my cars were automatic transmission cars.
Lynn

Lynn my original owner 1970 350/300 base engine with 3:08 and turbo 400 has the caps. I saw somewhere in literature that the letter identification stamped on my 70's rear is listed as heavy duty.

[Steve L.]

Re: Half Shaft U joint torque method

I'm the original owner of a 73 #20142. It has u bolts. The universal was replaced after about a yr by Mr Goodwrench, so he may have swapped out the caps. Mr Goodwrench also did other strange things like grind out a home made wedge to jam into the TA shim stack because he couldn't get proper shims. He also lifted up by the struts, put in regular diff oil which caused a clunk.

[Ridge K.]

Re: Half Shaft U joint torque method

I'm the original owner of a 73 #20142. It has u bolts. The universal was replaced after about a yr by Mr Goodwrench, so he may have swapped out the caps. Mr Goodwrench also did other strange things like grind out a home made wedge to jam into the TA shim stack because he couldn't get proper shims. He also lifted up by the struts, put in regular diff oil which caused a clunk.

My 34 year old son is the lead service advisor at a major "heavy-hitter" dealership. The seven mechanics assigned to his team work (on good days) grueling 10 hour shifts, and 12 hours on overloaded days. Many of the cars they service have six figure window stickers. The dealership owner is a corporate monopoly that cracks the whip to push more & more service out the door, while new car sales are depressed from this recession.
Those of us who are armchair mechanics, would be shocked at short-cuts taken in an effort to boost work orders out the door.
I am not defending this practice, nor condoning it. Don't shoot the messenger here.... I'm only saying that if one things every repair is completed exactly as some thick book says it should be preformed, then one should spend on afternoon in the service area of a major dealership. That is life in the fast lane.
Ridge