hello, i am new to the c3 corvette, i have a 79 . the rear irs keeps dropping over time and adjustment wearing the tires quickly on the inside, is this a common problem ? or is it just worn and need to be rebuilt ?

 

I would check the trailing arms. If they are worn, the rear tires will show excessive wear on the sides.

There are bushings at the front of the trailing arms and bearings at the hub. If they are worn, there are vendors who can rebuild them (Bairs, Van Steel, Paragon, Willcox)

Bob K.

 

What exactly do you mean by "the irs keep dropping"? The rear suspension goes out of alignment? If so, no it's not supposed to do that.

 

[makin=jcrash68;1592622375]hello, i am new to the c3 corvette, i have a 79 . the rear irs keeps dropping over time and adjustment wearing the tires quickly on the inside, is this a common problem ? or is it just worn and need to be rebuilt ?[/QUOTE]

From your description, it sounds like you're experiencing excessive negative camber - that wheel appears to be tilted in at the top. This is adjusted to be more vertical by use of the strut rods - the smaller diameter rod directly under the axle (Please note that these sometimes 'run out of adjustment' and bubba will heat them and bend them to become shorter. They should be straight.)

If the strut rods are bent, replace. If they do not have enough adjustment, your problem lies in the differential. The inner splined stub axle end bears against a surface in the differential as it rotates. This surface wears, gradually making the total axle length shorter and tilting the top of the tire in. To repair, stub axle must be replaced. (Please note that reconditioned stock axles are available that have been restored to stock dimensions by the addition of a hardened steel button to the wear surface.)