U Joints and grease fittings

[baddriver]

I've seen a lot of people mention that the u-joints with grease fitings are weaker than those without, and you should never use these joints on the drivetrain of a Z. However, I have a question and I wondered if I could get some opinions on it.

 

I recently got u-joints for my stock 6 cyl z, and they came with grease fittings. However, unlike older u-joints I had seen that have the fitting in between two bearing caps on the center of the joint itself, this one had the fitting in the bearing cap, and only the center of the U-joint was hollow to allow grease in.

 

I looked at another u-joint without a fitting and found that this was hollow as well. I know that hollow tubes are stronger for their weight than solid tubes, so I was wondering if U joints with the fitting in the cap are really weaker than other u-joints, or if this was only true with the older style that put the fitting on the body of the joint?

 

Personally I think it's nice to be able to grease the joint, but I thought I'd ask around a bit before I decide what to do. The brand I have is "Brute force."

[SpeedRacer]

If you get a chance to see the U joints that are split at the drag strip you will see that almost all of them are split through the grease fitting hole.

 

Buy the ones without the fittings.

[A. G. Olphart]

It would be difficult to break the joint you have (lubed through the cap) in the manner SpeedRacer indicates as the common failure mode .

 

I think your logic is sound, and it was the zerk hole at the base of the cross that gave lubeable joints their bad reputation. The cap lubed joints appear to be the industry's answer to that problem.

 

Brand vs. Brand, I haven't a clue... but all other things being equal, more needles in the cap will give a longer service life because the load is spread among more lines of contact.