The new pin in my u-joint is quite snug. But the pin is loose in the driveline.
Do I need a new driveline?
Did you peen the ends of the pin? They should be peened. That will tighten it up and keep it from falling out. You will need to put something in the hole under the pin and peen the top end. Use a large punch and hammer to do this. Then rotate the driveshaft and do the same with the other end.
Tom, to add to what Norm just suggested, lay the pin across the jaws of a vice open half the length of the pin, and give it a few easy love taps with a hammer to give it a slight curve. This will give you a nice tight fit when you drive it in, then peen the ends.
Norman and John,
I haven't installed yet.
So what you both are saying is the fact the driveshaft hole is a bit larger than the tight U-joint hole is not an issue, as long as I do what you suggest?
If I remember correctly, when I took everything apart, I saw a bend in the pin.
Tom, how loose is the pin when you insert it in just the driveshaft? Is it really loose compared to the u-joint hole?
I just put my rear end back together. The holes in the U-joint and drive shaft were slightly different diameters. I match drilled the holes. I then peened the rivet which expanded it for a tight fit.
When I took it apart the rivet that came out was too small and not peened. The bushing had not been faced correctly. The rivet had been rubbing on the inside of the drive tube. The correct rivet would not fit and I had to take close to 1/16 off the face of the bushing to get a good fit (zero clearance).
The rest of the rear end had similar issues.
John, I am sorry, at the moment, I only have my drill bits to measure the holes. The holes in the u-joint are 9/32, with one side being a tad more loose than 9/32.
The hole in the driveshaft is a tad more loose than 19/64 on one side and a tad more loose than 9/32 on the other side. The brand new pin measures .274. The pin is very tight, really doesn't fit in one side of the u-joint, and is a bit sloppy on the other side of the u-joint. It's much more sloppy in the driveshaft.
I was thinking per what Neil said, what about match drilling the u-joint and driveshaft holes and using a larger diameter pin?
Tom, if you have different size holes on both sides of the D/S and U-joint, i think Neil has the right idea of match drilling. Just make sure when you buy an oversized pin you get one that is fairly soft compared to the tube. Maybe someone here can recommend what grade pin to buy. Good luck and let us know how you make out.
John Regan (whose opinion I highly respect) recommended a steel alloy called "Ledloy" for u-joint pins. It's pretty commonly available at on-line suppliers.
" Ledloy, a carbon steel with lead added to make the material machine better. Typical specification for 12L14 alloy is:
Carbon 0.15% max
Manganese: 0.85% to 1.15%
Phosphorus: 0.04% to 0.09%
Sulphor: 0.26% to 0.35%
Lead: 0.15% to 0.35%
C12L14 is a lead-bearing cold drawn steel.
It offers inherent ductility combined with finer surface quality.
It can be bent crimped and riveted.
Since 12L14 is an extraordinary machining steel it has become the favorite carbon metal for machining - especially on light weight lathes.
12L14 has a smooth cold finish (rolled) surface.
Yield strengths are approx. 60000 PSI range while machinability is rated at 195% & 325 surface feet per minute.
John, many thanks!
Dick, thanks, I just found that rod material in the correct size (5/16").
Do either of you or anyone know if over-sizing the U-joint and driveshaft holes will cause a problem?
If you drill it oversize within reason it should not cause any problems. Just don't go to 1/2 inch. (I am exaggerating.)
That pin is only to keep the driveshaft forward and the u joint against the thrust bushing. The pressure on the pinion gear is toward the front and the torque will be against the square end of the shaft inside the U joint. You don't need to get too finicky about the fit of the pin. It fits snugly in the shaft and if you drill it out, someday when someone replaces the U joint the shaft will be drilled out too far. Just peen the ends and you should be fine. There is really not a lot of pressure against the pin.