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greasable u joint failure pics

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Old Nov 2, 2008 | 06:13 PM
  #1  
1980 blue L48's Avatar
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Default greasable u joint failure pics

My weakling 1980, 190 HP, all stock, B&M shift TH350.
I took off let it rev out in drive, then BOOM. No
warning, they were the greasable type. I walked back
up the road and found what was left of the sheared trunnins.I
knew the solid joints were the best, but never figured this
car would do this. I`ve let it rev out, then chip the tires in second
at least 30 times maybe more, before today. WARNING If you can grease your joints, REPLACE them before this happens to you.




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Old Nov 2, 2008 | 06:40 PM
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Never ceases to amaze me when I see the damage caused by flailing half shafts and drive shafts.
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Old Nov 2, 2008 | 06:54 PM
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I'm not a fan of the greasable type but that failure was not due to the type,
it was because they were run without grease and then greased after it was too late.IMO
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Old Nov 2, 2008 | 06:59 PM
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it was because they were run without grease and then greased after it was too late.IMO
How does greasing them after they've dried out cause the failure?
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Old Nov 2, 2008 | 07:06 PM
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Originally Posted by FlyViper
How does greasing them after they've dried out cause the failure?
I wasnt saying that greasing them caused the failure only that they were probably all ready worn and then they were greased.
Also looking at the pics again one of the bolts appears to have been loose.
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Old Nov 2, 2008 | 08:20 PM
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The joints WERE NOT worn at all, Im sorry your wrong! They were in good condition NO needle marks were on the trunnins.I have never needed to have greased them.The trans did shift extremly firm, I feel this was the reason for failure.
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Old Nov 2, 2008 | 08:30 PM
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How old were they, might be a clue as to why they failed.
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Old Nov 2, 2008 | 08:39 PM
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Originally Posted by 1980 blue L48
The joints WERE NOT worn at all, Im sorry your wrong! They were in good condition NO needle marks were on the trunnins.I have never needed to have greased them.The trans did shift extremly firm, I feel this was the reason for failure.
OK...I thought I was seeing needle marks in the second pic.
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Old Nov 2, 2008 | 08:58 PM
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I have owned it 3 years in March. I have no idea how old they were. The inside joint on this shaft was a solid type. The other side is the same way. Grease zerk on outside, solid inboard.
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Old Nov 2, 2008 | 09:04 PM
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When a greaseable joint fails because of its design, it fractures at the Zerk fitting...right through the body...due to stress fracture at the thread area. I agree that the failure wasn't due to the grease fitting design. It just looks like the joint was overpowered...possibly from some violent wheel hop under high load.
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Old Nov 2, 2008 | 09:05 PM
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It also appears like the u-joint was put in backwards.The zerk looks like it was towards the wheel,that makes it tough to grease.
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Old Nov 2, 2008 | 10:40 PM
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I agree. Greaseable u-joints will fail like that if you never grease them
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Old Nov 2, 2008 | 11:02 PM
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i grease mine every other year, and ive beat the hell out of my car. havnt had a problem with them.
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Old Nov 3, 2008 | 12:44 AM
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geez mate that would have given me one hell of a fright. that must have made one hell of a noise and comotion through your steering wheel. i dont know if i would blame greasable uni,s so fast but. i have been running them for a long time on a reasonable strong motor, about 450 hp which cops a flogging all the time and no problems so far. i do grease them every 6 months but until i hear the first little pop noise. NO MORE...otherwise the seal blows out. you said............

The joints WERE NOT worn at all, Im sorry your wrong! They were in good condition NO needle marks were on the trunnins.# I have never needed to have greased them# .The trans did shift extremly firm, I feel this was the reason for failure.

you said you have never needed to grease them before , and is that in 3 years? there is your answer between the hash marks i think. and holy %^&*& did it smash your brake calliper as well or is that just a paint crack. what a demolition job it did.im going outside to grease mine right now

Last edited by gingerbreadman1977; Nov 3, 2008 at 06:02 AM.
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Old Nov 3, 2008 | 07:16 AM
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Originally Posted by 7T1vette
When a greaseable joint fails because of its design, it fractures at the Zerk fitting...right through the body...due to stress fracture at the thread area. I agree that the failure wasn't due to the grease fitting design. It just looks like the joint was overpowered...possibly from some violent wheel hop under high load.
This is my understanding of the weakness in the design. The threaded hole for the fitting weakens that area of the joint body. The fracture would have occurred there if in fact the design was at fault. In this instance the failure was elsewhere, suggesting other factors were at play.
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Old Nov 3, 2008 | 09:05 AM
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Originally Posted by 1980 blue L48
The joints WERE NOT worn at all, Im sorry your wrong! They were in good condition NO needle marks were on the trunnins.I have never needed to have greased them.The trans did shift extremly firm, I feel this was the reason for failure.
I'm thinking you'd be hard pressed to break even worn out u-joints with 190 hp and a slush box.
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Old Nov 3, 2008 | 09:29 AM
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Originally Posted by DWncchs
I wasnt saying that greasing them caused the failure only that they were probably all ready worn and then they were greased.
Also looking at the pics again one of the bolts appears to have been loose.
I agree with your statement. One of the bolts looks as if it is bent from being loose.
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Old Nov 3, 2008 | 08:59 PM
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Well that settles it for me. I was going to leave the old greaseable U Joints in my 75 as I rebuild the rear suspension. From seeing the photos, and the comments, I think replacing them with solid units is the way to go. They are $15 each, but the piece of mind of having new units may be worth it.

How often do you have to grease - greasable U Joints. Is it every year? If you dont grease them in 3 years would that be a contributing cause to failure.

kdf
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Old Nov 3, 2008 | 09:16 PM
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Can anyone explain why a greasable u-joint that is only greased once at installation time would not last as long as a non greasable joint. Assuming neither had a structural failure ? Why would one outlast the other ?
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Old Nov 4, 2008 | 06:58 AM
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Originally Posted by bashcraft
I'm thinking you'd be hard pressed to break even worn out u-joints with 190 hp and a slush box.
i agree basher. normally they start clicking horribly when the grease dries out before they go WHAM like that. maybe the loose bolt theory giving it some play like a few have said. either way im sticking to greasable for now but good to see some pictures 1980 blue. i hope you fix it well and have it going better then ever soon.
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