tmscarguy

ok, i appreciate all the help with the rear alignment question i posted. i had the car aligned, the bushings and bearings seem ok. but, the axle shaft that goes into the rear end has some slack in it. it goes in and out 1/4 inch or so with the car jacked up. it does this when you hold the tire at 6 & 12 and push/pull on it. nothing else moves except that shaft goes in and out. this car only has 27k on it. surely the rear end wouldn't be wore out. would it?
thanks, bob

MelWff

that would indicate the stub axle is worn, who rebuilt the rear end? Can you see if they stand behind their work?

tmscarguy

as far as i know it hasn't been rebuilt. it is original.

MelWff

I dont know what the specs are for it but a 1/4 inch sounds like a lot. Wait to see if someone else chimes in and leaves a comment. Have you ever changed the rear end fluid? Does it have the same play on both sides? The ends of the shaft I believe are soft and wear. The replacements use hardened shafts.

Gordonm

Yes it sounds like the axle shafts are worn down. Common problem on these Corvettes. I don't like to see anymore than .050 on a old set and a new set you should see a lot less. You say you have 1/4 inch or .250 that is a lot of movement. The rear will need to be removed and most likely rebuilt with new or replacement axles.

muskegonbrake

I've never seen a hard and fast spec for end play, but the end of those axle shafts do wear and can pop the clip. If you've got 1/4" you should really think about doing a visual inspection of the yokes.

Jim_Harrison

That much play might just be a broken snap ring. You would need to pull the diff., open it op and install a new one.

thegazman

The C-clip that hold you stub axle in the differential has come off. I learned this from experience.Pull the spring and the differential cover. The grove in your stub axle is probably worn. Install a new stub axle and c-clip.

bashcraft

Those clips have been missing from my stub axles for the 31 years that I've owned the car. Never been a problem.

tmscarguy

havent changed the rear end fluid. the driverside has a little less play but not much difference.

Bugman Jeff

This reply leads me to the question, just what is their purpose? I mean, obviously, they keep the stub axles in the diff, but are they really necessary? The stub axles can't really go anywhere when everything's assembled. They're not subject to the side loads that a C-clip axle is, and the axle won't come flying out if you lose a snap ring. Are the snap rings an actual necessity, or were they put there for convenience to hold the stubs in during initial transport of the parts and assembly of the chassis?

muskegonbrake

Keep in mind that the half shaft is the upper control arm in this system. If you have some sort of lower control arm catastrophic failure and there is nothing keeping the upper control arm from pulling out of the differential you could lose the entire trailing arm assembly on one side. I know that normally it doesn't really affect anything but I wouldn't be comfortable going without.

Mike Ward

This issue was thrashed to death fairly recently. For reasons unknown, the entire thread was deleted (not just closed).

In summary, the suspension geometry forces the half shaft inwards under all conditions with the wheels on the ground. There are plenty of cars running around with no snap rings in place either deliberately or unbeknownst to the owners with no negative effects.

Jim_Harrison

Not sure I agree with this. Under hard braking and while turning, couldn't this let the indide tire have negative camber, since it isn't loaded? For a street car I wouldn't be too concerned, I've worked hard to take as much of the slop out my rear suspension as possible.

classicvettefan

Sounds like the stub axles have excessive end play. Remove the Half shafts and using a dial indicator mounted to the trailing arm measure the in/out end play on the axle should be .001 to .004 no more. Tight side is best.

Mike Ward

If you don't believe it , you can go do the analysis that I and least two other members did. I stopped at 1G lateral force, one of the other members continued on way past that and found that at any condition below 1.3G (IIRC) there is positive load on the half shaft pushing inwards. Static load is 300lbs.

TheSkunkWorks

Not sure that theory fully takes into account lateral forces and slip angles...

63mako

If the C clips were not needed they would not have been installed in the first place. I don't think someone's theory would change many peoples mind on this. Hard to calculate the side load forces this will see under extreme cornering hitting a pothole.

drwet

I remember taking a course in Bloomington years ago about Corvette rear suspension. I forget who put it on but he was very knowledgeable and he told the story of a Corvette that had lost its circlip from the rear and the side yoke actually came out of the rear end with catastrophic results. Hard to imagine, but I don't think it makes sense to be driving around in one of these cars with a known defect of this magnitude. If the yoke is worn enough that the c-clip has fallen out, it should be replaced. Its not that big a deal. It will take a day or two, but there's no magic to replacing them. A new set of yokes will cost you about $3-400. You can probably count on a couple hundred more if you replace all the worn parts you find while you have it apart.

thegazman

The reason I noticed a c-clip was missing was the rear end of my 79 was squirrely on curvy roads here in WV. A missing c-clip definently makes a difference in handling on curses as the stub axle slips in and out of the differential. If you always drive on straight roads you will probably never notice the slop in your rear suspension.