Broken U-joint

[Spencer]

I was having really bad vibration over 55mph. I thought it was the tires being out of balance, but I just got new tires and an alignment two days ago. The vibration was still there, so I took the driveshaft out to inspect. Look at what I found:

I don't even want to know what would have happened had I kept driving like this. I replaced it with a new one, and the difference is unbelievable. Drives smooth as silk now.

 

[Skandocious]

Holy crap... Hard to tell from the second pic but... Did it damage the yoke?

 

[Spencer]

Yes, the u-joint was so loose it started to eat at the yoke. I was a little worried, but I put the u-joint in and it was firm. Still plenty of material left. Scary stuff though, I'm really glad I fixed this.

 

[Skandocious]

Keep an eye on that yoke... Regardless of firmness, the overall strength is degraded and you could blow out that yoke with enough torque.

 

[Spencer]

True. It is definitely better than it was. I will probably replace the bad piece, but this was the first step in getting it ok to drive. I'm 2wd and I usually drive pretty mild, so I think it will be ok for now.

 

[1985 Ford F-150]

Yep Ive seen some bad oness like that as well. I had an axle u joint blow out on my 76 and it started to wobble out the hole cause it blew one of the caps clear off. Ive been runnin it for a year like thaat and four wheelin with it and its been fine.

 

[Skandocious]

I had an axle u joint blow out on my 76 and it started to wobble out the hole cause it blew one of the caps clear off. Ive been runnin it for a year like thaat and four wheelin with it and its been fine.

There is so much wrong with that post... You do realize the yoke hole without a cap is currently getting hollowed out into an oval shape, right? This happened to one of the jeep guys on our snow trip-- he blew off two caps from his front axle shaft and it hollowed out the holes on the yoke-- now he has to replace the u-joint AND the axle stub shaft.

 

[Spencer]

I think maybe he meant he's been 4wheeling like that after he replaced the U-joint? I hope so anyway.

 

[1985 Ford F-150]

Yeah I put a new one in there I forgot to put that in the last post. I meant to say after I fixed it ive been drivin it with a wobbled out hole on the shaft.

 

[Skandocious]

Yeah I put a new one in there I forgot to put that in the last post. I meant to say after I fixed it ive been drivin it with a wobbled out hole on the shaft.

Oh... Gotcha. Well still-- it may not be a good idea to be driving with a hollowed out hole on your axle shaft. You're liable to throw another cap and maybe do MORE damage.

 

[Spencer]

How does it to compare to the pic I posted? Better/worse?

 

[Spencer]

The damaged hole in mine was not hollowed out, it was just missing a chunk. I think it would have became hollowed out had I kept driving on it.

 

[1985 Ford F-150]

It wasnt overly bad but it was worse than yours. I really dont care anymore that trucks gettin sold.

 

[radialarm]

You've lost about half the socket on that and if I were you I'ld go to a wrecking yard and get another fast. Two wheel drive or not, and driving mild wont help either!!!

 

[Spencer]

Yes, I plan on replacing it. I'd rather not chance it.

 

[LEB Ben]

Holy Crap...makes me nervous about what I'll find with mine. I too just got new tires and a recent alignment, still have a slight vibe. Guess I oughta throw that on the to do list.

 

[Alvin in AZ]

Every time I post this it gets made fun of and comments about safety etc
...which are all good, IMO.

Anyway, if you've got a level place to work, put the sucker up on blocks.

Start the thing up and put it in gear and have someone hold the gas pedal
or I usually just prop something on the gas pedal and get it going at the
problem speed on the speedometer.

Look at the spinning wheels and check for bent axles or crooked wheels or
tires out-of-round but more important look at the drive shaft spinning. If it's
worth keeping "as is" it will be spinning in place and look pretty and straight
as anything! Like the fine piece of machinery it could/should be.

If it's not spinning smooth and straight as anything... just take it off and
take it the drive shaft shop and tell 'em to "fix it". Easy as that.

Has worked for me.

IME, if there's something wrong, like 1 bad U-joint, the whole stinkin drive
shaft is suspect! If it's a farm truck that's another story if it's a highway
truck that you want to "run like a top" then a drive shaft shop is the way
to go.

They'll straight it and balance it and it'll make all the difference in longevity
of the equipment connected at both ends of it too. See it?

I've had all three of these things at the same time on my pickup before...
-crooked out of balance rear drive shaft
-crooked steel wheel (from an after-market factory)
-bent axle

You don't know what you are going to find until you look.

Alvin in AZ