Concerned About U-Joint Pin

[RustyFords]

I installed a new u-joint as part of my axle/torque tube rebuild and with it, a new pin to secure it to the driveshaft.

I used a punch and hammer to peen the pin on both sides but I never really got it peened the way I wanted it to be. It's good mind you, but not perfect.

I'm wondering how much damage this will do if it comes undone and slings out to one side. Should I be concerned about this? I have the modern pinion bearing installed and have heard that you don't really need the pin on the u-joint if you're running the modern pionion bearing.

So...yall please educate me. Should I be concerned?

If it's true about not needing the pin, I may just remove it before I start driving the car.

If it's needed...I'll get back in there and peen some more.

[RajoRacer]

I peen one end good in a vise then insert into u-joint then I screw a late fan arm (same thread as the plugs) into the side that was already peened over, snug up & using as an anvil against the floor or wood block or ?, snug down then peen away.

[RustyFords]

I peen one end good in a vise then insert into u-joint then I screw a late fan arm (same thread as the plugs) into the side that was already peened over, snug up & using as an anvil against the floor or wood block or ?, snug down then peen away.

That's pretty much what I did, and it's peened on both sides, but it's not tight on both sides.

[Norman Kling]

In order to peen the pin on both ends you must support the bottom. Use a large punch or other round piece of steel which will fit into the hole in the housing. support it with something which you can put under the car so that it solidly holds it against the already peened end of the pin. Then use a large punch to peen the top end. You should be able to get it tight that way. I would not recommend threading a bolt or water pump shaft into the hole because the process of peening could strip the threads or distort the housing. Actually this works best if you install the universal joint while you have the rear axle assembly outside the car when you rebuild the rear axle.
Norm

[RajoRacer]

I peen mine tight, Don.

Expanded info from above - take an "orphan" fan arm bracket bolt & use a countersink or 5/16" drill bit and make a shallow cut on the threaded end for the head of the already peened rivet to fit into then thread the bracket bolt into the housing plug hole snug against the previously peened rivet head - flop the entire rear axle assembly over so the fan arm bracket bolt head is on a solid base (floor) and peen the opposite rivet end tight - I've done dozens of u-joint pins this way Norman and never messed up any threads - the bracket bolt is essentially an anvil & the weight of the entire rear axle assembly won't allow movement.

[Scott_Conger]

Steve

that is such a common sense, yet clever idea! I love it! Man, this tip is worth all the random searching I've done this week while waiting out frigid temps in the barn. THANKS!

I'm humbled that I didn't figure this out for myself...seems obvious now... Always something new to learn.

[RajoRacer]

You are most welcome, Scott - I believe the whole idea of being a "hobbyist" is to share - always worked for me !

[Oldav8tor]

I drill a shallow hole in each end of the pin, install it with both ends sticking out of the U-joint equally. I then screw a fine thread bolt (aircraft - AN bolt) into one side and run it up against the pin. I then rest the housing over the jaws of a vice with the bolt clamped in the jaws. This is so the threads in the housing are not subjected to all the force of pounding on the pin. I then use a pointed punch to peen one end and then repeat the above process with the other. It seems to set the pin in pretty good - it's definitely in more securely than the pin I removed to disassemble the driveshaft.

[Jerry VanOoteghem]

Lots of good advice above.

To answer one of your other questions, YES, you still need the pin even if you're using the modern pinion bearing.

[tdumas]

I make my own pin with a head on it. Then install it and back it up with a bolt to peen the one end.

In my opinion the pin merely holds the u-joint in place when assembled.

The thrust is always toward the engine and the pinion is restricted in moving aft by the ring gear. It could be left out and the u -joint could float and find its own position. Others may disagree and that's ok.

[daren007]

Unless I missed it the question was "how much damage...…" There were a lot of answers on installing the pin but none that I found on how much damage would be caused if the pin came loose.

[Original Smith]

I've seen replacement pins made in the old days, that had a head on one end. It would be cool if one could be made today.

[Rich Bingham]

Damage ? Hard to predict, and dependent on a lot of factors. I've seen housings "ringed" inside by dragging a loose pin.

[Adam]

To answer the original question; that depends on what type of plugs you have installed. The original plugs are slightly cup shaped on their ends, the reproductions plugs are flat. The original style plugs will be even with the inside of the driveshaft housing while the reproduction plugs stick out a bit . If you are using the original style plugs and the pin breaks, the pin usually will not not hang up on the inside of the housing and likely won’t cause any further damage. You may even drive thousands of miles without even knowing the pin is broken since they generally break in only one place and still hold the U-joint in proper position. With the smooth transition over the plugs in the housing, the two broken pieces of the pin will generally stay in position because there is nothing for them to snag on. This is what I’ve observed having taken probably 40 or more drive-trains apart. I’ve seen many broken or loose pins that were still apparently doing their job just because there was nothing for them to snag on.

[RustyFords]

Good information everyone...thanks.

My plugs are originals Adam.

What do yall use for the peening process? I was using a hammer and punch and this is where most of my "failure to fully peen" came from. It seemed that I just couldn't achieve the control that I normally can when striking directly on an object with a ball-peen hammer. I'm wondering if a hammer with a very narrow head might work. I've seen some tack hammers that seem like they might work.

[RajoRacer]

I use a large drift pin and good sized ball peen hammer and go around the edges of the pin first to start then hammer away.

[Mark Nunn]

I've read other posts on this forum that you should lay the pin over an open vice with pin ends supported. Then strike the center of the pin to give it a slight bend. That helps hold the joint rigidly. I have not don't that yet but I will when weather permits.