Do U joints have to align in any way

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boltbrain

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I just put a new carrier bearing on my 79 K20 and realized I didn’t note if the three U joints aligned in any way, does it matter whether they are parallel to each other? Or maybe the least parallel is best? I not marked the position of the rear one on it’s differential so am hoping there’s no great balance issue with the tranny. Thanks
 

boltbrain

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Meant to say, I only marked the rear one’s location
 

boltbrain

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Thanks, I’ll line them up as long as it’s still out
 

SirRobyn0

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I'm also going to add that some trucks have where the rear drive shaft sides into the front keyed. In that case there really isn't any concern of phasing.
 

RecklessWOT

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Yes, very important to have your drive shaft in phase. This video shows what happens if they are not in phase:

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well I'll be.

Never knew about this, I guess you learn something new every day. I always wondered why people mark their driveshafts, I always thought "who gives a sh!t, what a waste of time", figured it was just being overly anal like those people who use a torque wrench to tighten their lug nuts, or the ones who are afraid to remove their EGR and pull cool clean air into their engine because "oh no it's gonna overheat the combustion chamber" (that'll ruffle some feathers lol ;)). But holy crap I guess it really does matter and I guess I've just gotten lucky in the past, never realized such a phenomenon existed
 

QBuff02

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well I'll be.

Never knew about this, I guess you learn something new every day. I always wondered why people mark their driveshafts, I always thought "who gives a sh!t, what a waste of time", figured it was just being overly anal like those people who use a torque wrench to tighten their lug nuts, or the ones who are afraid to remove their EGR and pull cool clean air into their engine because "oh no it's gonna overheat the combustion chamber" (that'll ruffle some feathers lol ;)). But holy crap I guess it really does matter and I guess I've just gotten lucky in the past, never realized such a phenomenon existed
I'm one of those overly anal guys when it comes to torqueing wheel hardware. Been turning wrenches since high school and have made it my (almost 24 years so far) career. I grew up around the hay days of "Mr. Goodwrench" and a couple of my dads friends at the time were certified gm mechanics and they always said if you wanted your brake components to last then while installing the wheels it is NOT the place for an impact gun and torque specs are there for a reason. I've lived by that since a young age and always torque the wheel hardware on everything I touch, my '04 Silverado went just over 130,000 miles on the original brakes and my '12 just had the original front brakes changed last fall at 174,000 miles. No brake chatter or warpage on either, simply replaced due to old age and finally wearing out. And the best part, my 115 lb step daughter was taught how to change flat tires when we got her her first car, and i showed her the difference of ease in breaking lug nuts loose if they're properly tightened vs. ones that are overly tightened. She was jumping on the breaker bar and couldn't get them to budge but on a torqued wheel she could pull the lug nuts loose with a little tug using her upper body strength. And it gets the kids out in the garage because they like to make the torque wrench click while helping me so it's a win-win. Kind of like properly phasing driveshafts. Lol
 

RecklessWOT

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I'm one of those overly anal guys when it comes to torqueing wheel hardware. Been turning wrenches since high school and have made it my (almost 24 years so far) career. I grew up around the hay days of "Mr. Goodwrench" and a couple of my dads friends at the time were certified gm mechanics and they always said if you wanted your brake components to last then while installing the wheels it is NOT the place for an impact gun and torque specs are there for a reason. I've lived by that since a young age and always torque the wheel hardware on everything I touch, my '04 Silverado went just over 130,000 miles on the original brakes and my '12 just had the original front brakes changed last fall at 174,000 miles. No brake chatter or warpage on either, simply replaced due to old age and finally wearing out. And the best part, my 115 lb step daughter was taught how to change flat tires when we got her her first car, and i showed her the difference of ease in breaking lug nuts loose if they're properly tightened vs. ones that are overly tightened. She was jumping on the breaker bar and couldn't get them to budge but on a torqued wheel she could pull the lug nuts loose with a little tug using her upper body strength. And it gets the kids out in the garage because they like to make the torque wrench click while helping me so it's a win-win. Kind of like properly phasing driveshafts. Lol
Oh don't get me wrong, I don't impact my lug nuts on that's a good way to warp brake rotors and ruin wheel bearings on some cars. I just don't go crazy and bust out the torque wrench to make more work for myself either, man I hate putting away tools. I just make them "lug nut tight" by feel. Never had a problem. I've never torqued a spark plug either, just know how they feel. I literally use that as a way to explain things too, hah you'll literally see programs I wrote at work with notes instructing some of the other machine operators to "tighten the fixture until it feels 'spark plug tight' ", and nobody has ever come up to me asking what I meant. I always assumed that's just how everyone does things (unless you're building a race car or something). I reserve the use of torque wrenches for head bolts and internal parts, etc. It gets used maybe once a year if that? I laugh when a set of valve cover gaskets or something comes with a set of instructions and include torque specs, it's called "scrape the old ones off really good and don't crank the hell out of the new ones or it'll leak". Idk always just figured it was common sense when working on any type of machinery, you can feel when you're crushing a gasket too much or in risk of stripping threads. I've only ever worried about very critical parts.

I know what you mean about having them too tight though, there was one time a couple years ago I was in a time crunch and I had no choice but to bring my 2500 W/T to a shop to have a minor repar done (pains me to my soul to pay some other a-hole to work on my truck), while it was there he said he's rotate the tires for an extra 10 bucks because he already had the fronts off, so I figured why not. I ended up having to replace an axle seal a month or so later and I literally bent the factory lug wrench over itself trying to get the lug nuts off, when I resorted to sockets I broke two chrome sockets and a half inch ratchet until I finally had to resort to using a black impact socket on a solid T handle with a 4' pipe on it, they smoked when they finally broke loose. I considered going down there and putting my truck through the wall of his shop but I let it go. I need a new set of tires soon, that tire shop is gonna have fun with this one...
 
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Other than phasing the yokes (which is not normally an issue on squares,) I will provide the OCD/Anal Retentive view:
If the grease nipple points out at a slight direction, ensure you are able to connect a grease gun to it.
And if you are SEVERELY OCD: ensure the u-joints are installed such that the grease nipple is under compression when the vehicle is under acceleration.

Yes, I DO that. Can't resist the urges.
 

SirRobyn0

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Other than phasing the yokes (which is not normally an issue on squares,) I will provide the OCD/Anal Retentive view:
If the grease nipple points out at a slight direction, ensure you are able to connect a grease gun to it.
And if you are SEVERELY OCD: ensure the u-joints are installed such that the grease nipple is under compression when the vehicle is under acceleration.

Yes, I DO that. Can't resist the urges.
I feel your pain. I've actually gotten a little bit better about that stuff as I've gotten older, but there was a time that I had to turn my hose clamps so the screw part was out of sight, and did something similar with u-joints to what you describe. IDK I still think about that stuff but it no longer bothers me.
 

boltbrain

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Other than phasing the yokes (which is not normally an issue on squares,) I will provide the OCD/Anal Retentive view:
If the grease nipple points out at a slight direction, ensure you are able to connect a grease gun to it.
And if you are SEVERELY OCD: ensure the u-joints are installed such that the grease nipple is under compression when the vehicle is under acceleration.

Yes, I DO that. Can't resist the urges.
How does one ensure a U joint is installed such that a grease nipple is under compression, and under compression from what? I’ve seen them pointed in and inaccessible, a sure sign of ineptitude
 

Tim Cyrus

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In addition to Turbo4Whl's link from Spicer on angle and phasing here is a good technique to insure phasing is correct.
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Vbb199

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The joints are to be 90° out from one another.
 

imaxm

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wow all these years and I never knew any of this! I'm waiting on the call from mechanic who is replacing every u-joint. I heard that the vibration was from lack of grease and balance of the shaft.
 

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