U-Joints With Grease Fittings...

[Patrick T.]

The U-Joints I have replaced on my car have a grease fitting (zerk) for periodic lubrication. My understanding is that grease fittings are no longer manufactured with U-Joints. The new ones I bought don't have them.

In an effort to find out how old these U-Joints are, does anyone know when they were discontinued, and are the new ones without fittings have the same longevity? Thanks, Patrick

[George Daina]

U joints w/grease fittings.....

make a weak u joint when compared to u joints w/out grease fittings. The grease is permanent in the joints w/out the fittings.

[Duke W.]

Re: U-Joints With Grease Fittings...

The OEM U-joints did not have grease fittings, but, but over the years, some aftermarket replacement joints did. I believe both the drive shaft and half-shaft U-joints are common with a number of other applications. The half-shaft joints are used on some medium duty truck driveshafts.

I think with today's greases, you're better off without grease fittings, and given the relative low mileage that our old Corvettes see, a new OEM type joint that's "permanently" greased should last a long, long time.

Duke

[Clem Z.]

Re: U-Joints With Grease Fittings...

on race cars we always made sure that the grease fitting hole was in the compression, not in tension to help add to the strength of the u joint. i do not know if this works but i never had a u joint fail that had a grease fitting.

[Joe L.]

Re: U-Joints With Grease Fittings...

Patrick-----

Original half shaft u-joints used on Corvettes did not have grease fittings. Drive shaft u-joints have not been of the grease fitting type since at least 1969 and, most likely, much earlier.

U-joints are available today both with and without grease fittings. Dana-Spicer, which manufactured most of the PRODUCTION and SERVICE u-joints for GM, currently has both available. Their "standard" variety has grease fittings; their "lubed for life" varity do not. The "lubed for life" are more expensive and the primary difference is that the seals on the "lubed for life" are superior.

In SERVICE, either type of u-joint will work well on a Corvette. The grease fitting type can be a bit deceiving, though. Usually, on a Corvette, especially a half shaft application, the u-joint needs to be replaced about the same time that it needs to be greased. In fact, I believe that's why GM used the non-greaseable type in the first place. Most of the time, if you dis-assemble a half shaft u-joint at 25,000 miles (or even less), you will find that at least one of the trunnions suffers from brinelling. That means the u-joint is history.