[1-bassman]

Hi, maybe someone can lend a hand here. My son and I have an 1981 (Auto) Corvette. We have made many modifications in the last 10 years or so but have had a ujoint problem well before the addition of any more than stock power. It eats half shaft ujoints like they are going out of style. I have replaced probably 20 sets in that time frame. I have used cheap, expensive, racing, and any other kind and brand that was recommended to us. None of them seemed to last for any length of time. As far as I know, there were only two years that Corvette had a smaller ujoint and our '81 is one of them. With that in mind, I changed all components from wheel to wheel to allow me to use the larger ujoints and half shafts. The larger ones did hold up longer, but still eventually failed. I can only come up with one idea. I am not positive, but I believe the original leaf spring in the back was made of fiberglass. We bought the car with a steel spring. My guess is that the fiberglass spring allowed the car to sit lower in the rear, which in turn would keep a straighter line from the rear to the wheel spindle. The car seems to sit a little higher than most Vettes of that same year causing an angle at all ujoints. It does not seem drastic, but the further away from straight you go, the more twisting the ujoints take. What I would try next is to lower the back end with the use of an extended bolt from the control arm to the spring, or maybe I can have the spring altered in some way. Any one have any other ideas.

Thanks,
Dennis

[Pony]

I'm not an expert on what would have come stock or as an option on your 81, but my Ecklers catalog lists a Stock Replacement steel leaf spring for 1963-82 (9-leaf x 2 1/2" wide) They also list several replacement Composite Monosprings as upgrades. The 1963-78 stock small block Block spring is listed as 9-leaf x 2 1/4" wide and the stock big block as 7-leaf x 2 1/4" wide. All spring to trailing arm replacement bolt kits are the same and an kit with longer bolts with 3 1/2" or threads (for ride height adjustment) was listed. I have a 7-leaf spring that I installed under my 74 small block ( in my gallery) I wanted a stiffer spring for cornering and adjusted the ride height with the longer bolt kit. With all that said and done, My u-joints don't cause problems. Could your problem be more along the lines of a Caster/camber alignment problem. Before my last rebuild I had a slight off road excersion and bent a strut rod slightly altering the camber. I didn't realize it and within 20 miles burned up the wheel bearings, started a grease fire that melted one of the caliper seals adding brake fluid to the fire and causing quite a bit of excitement. Anyway If you haven't done it I would have an alignment shop that deals with C-3s adjust the ride height and do and alignment. Hope this helps some. PONY

[1-bassman]

Thanks for reply Pony. I never thought of an alignment problem. I've never had a four wheel alignment done, maybe it's time. I thank you again.

Dennis