Original BB U-Joints

[Peter M.]

I have an original 55K mile 427/425 with all original U-Joints. So far everything seems fine - I drive the car with enthusiasm - no off the line aggression - just strong acceleration from a rolling start and fairly high sustained speeds.

Two questions - first - I assume that u-joint failures are fairly predictable - that they start to squeak and click and that catastrophic failures are rare events ? The second question - when it comes time to replace the u-joints - are there replacements that are "dead-on" in appearance and function to the originals?

[Joe L.]

Re: Original BB U-Joints

Peter-----

Usually, u-joints give some warning before a catastrophic failure. There are no guarantees, though. Although rare, they can and do fail catastrophically without warning. The worst problem is created if the half shaft u-joints fail catastrophically. What usually, then, occurs is that "loose" half shaft tears up underbody fiberglass.

Even though your car has relatively low mileage, the grease in the u-joints is OLD if they've never been removed from the car and serviced (original Corvette u-joints do not have provisions for zerk fittings). Plus, the half shaft u-joints on a 63-82 Corvette are worked VERY hard, since the half shaft is both a suspension AND driveline member.

I would recommend that you remove the u-joints and service them. If they are still ok, this will extend their service life. If they're not, you'll be able to determine that fact before a problem occurs.

Removing the drive shaft u-joints is not usually difficult. Removing the half shaft joints is a LOT more difficult. Among other things, the u-joint flange MUST be reinforced with a special fixture or an old spindle flange during removal and re-installation of the joints.

I am about 99% sure that you will find that at least one trunnion of each half shaft u-joint will be brinnelled (i.e. "indented" from roller bearings). If so, the u-joint is scrap. Even though the car is not currently evidencing any impending u-joint failure symptoms, you might even be surprised to find that you can "pour" the bearings out of the bearing caps in the form of "powdered rust". If you are lucky (VERY, VERY doubtful), all 4 of the u-joint trunnions of each u-joint will be ok. In that case, clean them up THOROUGHLY with solvent, pack with grease (GM #12377985 is what I use and recommend for this)and re-install. You MAY be able to save the driveshaft u-joints. I really doubt that any of the half shaft ones will be any good for re-use.

There are no currently available u-joints (except NOS if you can find them) that I am aware of that have exactly the configuration of the originals. The Spicer "lubed-for-life" type (i.e. without grease fittings as original) have a COMPLETELY different configuration. The u-joints available from GM are exactly these u-joints in GM boxes.

NEAPCO, the only other brand u-joint that I would even consider using, may or may not be currently "close" to the originals. I don't even know if NEAPCO makes a non-zerk fitting u-joint for these applications, though.

[frank mccracken]

Re: Original BB U-Joints

Joe and Peter; Neapco makes their "Brute Force" u joints without zerks. The brute force has a forged cross for strength. Performance ujoints do not have zerks because the hole is a weak spot in the cross. Every time I have broken a ujoint the crack always goes thru the zerk hole. FYI, thse ujoints have a RED neoprene cap seal instead of black.