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To ZERK or NOT? u-joints/h.s./ '71


Well-known member
Dec 27, 2000
Florence, SC (Timmonsville SC)
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
Will replace all 4 u-joints at half-shafts of '71 sb with stock tires-suspension-ride height. I have 2 reasonably-priced choices: those u-joints with zerks in cross (not in cap)... or those u-joints with NO zerks at all. Apparently, originals had no zerks in cross nor cap. I much prefer to have zerks. Does anyone know (or can reasonably predict) if there will be bind-up/wind-up/interferance between zerks in cross and adjacent flange/h.s.????
Thanks, Jack
Jack, My opinion is not to zerk. Here is why. 1st the zerks,or more so, the grease channels make the u-joint weaker. 2nd, they are very difficult to grease if you can grease them at all. The zerks will fit and won't bind up, but if you can't graes them they are not doing you any good. I have installed both however, when the choice is left to me, I don't zerk.:).........Steve
channel weakens joint...hmmm

Thanks Steve!

I don't think I'd have thought of that...until it was too late. There's no doubt grease channel would weaken it. Your measured thoughts may explain the following observation I made: I knew the the h.s. u-joints in my previously neglected daily driver were shot...but when I pulled the shafts I was stunned...(BTW I'd never looked at any vette h.s. u-joints)... I'd never seen a non-vette DRIVESHAFT with so much wear in the journals-caps that had NOT broken out/totally failed. But maybe all I'd seen previously were those WITH channels. Maybe mine survived breaking ONLY because they have NO channels. If so, that says volumes for no zerks!
I'm a zerk kinda guy

I buy GOOD Spicer u joints with zerks for my small block drivers, I'ts just easier to do the regular maintance. If I had a 350+ horse motor then I would not Zerk I do not care for the ones in the cap but the ones in the cross, a little lube goes a long way!

low-to-mid power w/ zerked h.s.


I've also wondered at what threshold of power-transmission combinations do zerks become too much liability. My 71 coupe has an automatic and I'm freshening sb motor now; expect 325-340 hp max...will never see the track but has very aggressive driver. Heck...I'm still guessing about many things...maybe I try w/ centered zerks...and hope for the best. Thanks, Jack
I don't know which way to go? The longest lasting ujoints I have ever seen were the ones origionaly installed. Nothing seems to last as long? I have never broken a ujoint in a nonracing application. And they were stressed way beyond what would be normal, even for racing. Install the joints so that the zerk fitting is under compression as the driveline rotates. That is the weakest point. Always buy Spicer joints, Some of the brand X joints are not even forged steel. I have found some that looked like compressed dirt!
Zerk Cont.

If your putting out that kinda HP then don't zerk & If your a bit on the agressive side then for sure go with NON Zerk & buy the best you can ( I still am a spicer kinda guy ) I had the tail shaft to drive shaft break on me ( Long time ago ) and It cost me a new tranny, Drive shaft, bellhousing & a bunch of fiberglass work. so don't cheap out here. If you have already done it Re do it!


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