Mechanic Fixes A Rusted 2011 F-150 U-Joint By Nicking The Ends Off The Drive Shaft With A Cutting Torch And Warns One Wrong Squeeze Bends The Ears

A rusty 2011 Ford F-150 rolled into the shop with a squeaky rear U-joint, and the mechanic behind the camera decided the quickest way out was a cutting torch. He nicked the ends right off the drive shaft caps and called it a day.

A vehicle being worked on in a mechanic's garage.

The shop owner behind the @SouthMainAuto channel says the truck is crusty, the joint squeaks when he spins it by hand, and the customer asked for a non-greaseable U-joint. Here is how the job went.

One Wrong Squeeze Bends The Ears And Makes The Clips Nearly Impossible

Before he lit anything, the mechanic laid out the one thing that can wreck this job. If you press the old joint out with a ball joint press, a socket press or a vise, anything that squeezes, you can easily bend the ears of the drive shaft inward.

Once that happens, he says, it becomes “theoretically impossible” to get the clips back on. You can also tap each end with a hammer, pull the clips and drive the joint out that way, but the warning stays the same. Be careful not to squeeze the ends of the shaft.

He Marked The Shaft, Fired Up The Torch, And Warned That The Caps Can Explode

He started by giving the factory bolts a little heat, since they sometimes carry thread locker, and the bolts came loose. Then he pulled the shaft and noted the joint looked original, with no grease fitting and that old factory look.

Before cutting, he marked the relationship between the drive shaft and the yoke so everything goes back in the right place. His first cut is always the top of the cap, which lets him see the inner part of the joint.

He gives a warning about this method too. “You do have to be careful, these will explode,” he says, so you have to be quick. In this case the first cap did not blow, and the cut came right down to the crack.

Do Not Set It On The Bench And Smash It Through

With the caps cut, the mechanic says to resist the urge to lay the shaft on a bench and smash the joint through. Support the bottom side of the jaw in a vise, he says, so the tapered ears are held up while you knock the caps down.

That support is what keeps the ears from taking the big squeeze. It was not perfectly clean, though. He admits he hit one a little too hard and broke a clip, and he explains that the new joint comes with fresh clips anyway, but busted ones make the old ones a pain to get out.

Two caps were rusty enough that pieces came out in bits. One piece of clip stayed stuck inside until he fished it out, and then the second yoke end got the same treatment.

The Step He Says People Skip, Then Get Mad At Themselves

Once the old joint was out, he cleaned the grooves where the clips sit. He used emery cloth, 120 grit, and says not to go too crazy. A small cutoff wheel on a Dremel tool also works well, and on this job he used the little wheel on a regular drill.

The old clip leaves a rust ring in the groove, and you can almost feel it with your finger as it goes by. The goal is not to remove metal, only the rust.

“You’ll be surprised how much rust will come out of those grooves,” he says, and he adds that it makes the whole job easier because you are not lining up a clip against an old rust ring. His blunt summary is that some people skip this step and get mad at themselves.

Waiting On The Parts Store And A Nice Floppy New Joint

He waited for the part to arrive from NAPA. It was a 231 U-joint, non-greasable, as the customer requested. He says that back in his four-wheel drive days he ran non-greasable Spicer joints almost exclusively, and they were the ones he broke the least.

To install it, he started the joint up into the cap, set a clip on one side, flipped it over, and made sure no rust bits were sitting on the cross. He lined up his marks, drove the joint down to the clips, and checked that each clip sat all the way in its groove. “Make certain you see it go in that groove all the way,” he says.

Then he gave the yoke a couple of taps so the joint centers up. A properly seated joint should be a little loose and floppy, because if it is really stiff, he warns, “you’re going to have issues.”

He cleaned the back of the flange on the truck, added blue thread locker to the bolts, and torqued them to factory specs. He chose not to replace the upper joint at the transmission, since it is not bad and likely never will be in the life of this truck. He also says the truck is super rotted and the rear brakes feel seized, so it is not far from the scrap heap.

His Takeaway Is To Do You, As Long As The Ears Stay Open

The mechanic says the torch method is just one of many ways to change a U-joint, and that the subject is touchy for a lot of folks. You can use an arbor press, a shop press, a ball joint press, a socket press or a bench vise, or even the hammer method.

His big lesson holds no matter which route you choose. Do not squeeze the ears together on a drive shaft, because then you have to spread them back apart to get the clips in, and that applies to both inside and outside clip joints.

Handy Notes For Anyone Tackling A U-Joint

Mark the shaft and yoke before you take anything apart so the balance and alignment return to where they were.
Support the jaw under the ear while you drive the caps, and avoid pressing the ears together.
Clean the clip grooves until they are bright. Rust left behind makes the clips fight you.
Keep the new joint loose. A stiff joint after install is a warning, and a few taps on the yoke usually frees it.
Use the thread locker on the flange bolts and torque to spec.

If you ever see sparks flying at your local shop over a squeaky drive shaft, now you know the story behind it.

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