I'm replacing the rear crossmember cushions during a differential repair on my 79. Does anyone know if the rubber cushion should touch at the top when installing the crossmember. When I raise the differential and bolt the crossmember there is about 3/8" gap between the rubber and the frame. I don't want to strip the bolts. Should I keep tightening? Or is the gap normal?

Thanks
Mike

 

I had the same question. My originals on my 1968 had the rubber upper seal directly facing/mounting the bottom of the frame. My repro's would only mount up to about 3/8 inch of the frame. I called (Corvette Brake Products ) VBP, who I had bought the repro's from and they said that was normal. They said that it was most important that the difference between the rubber upper seals to frame was equal on both sides. I also have a 1970 Corvette, and I went and looked at it. There the rubber upper seals are about 1/8 of an inch seperation to the frame. This is a factory original mounting arrangement, so I think you have to accept that there can be a seperation difference.

Actully I also asked the same question as you did on the National Corvette Restoration Society webpage (ncrs.org). Their answer was basically the same. Oh by the way. ... the bell shaped fixture on the frame that the differential busing fits into can be referred to as the "sombrero." I mildly ground down the interior of my differential bushings and the surface of the sombrero. When I mounted the differential crossmember and it's bushings, I rubbed lithium grease between the interior surface of the busing and the sumbrero. Maybe body weight will help push them closer together. At least the grease will prevent corrosion.

 

Thank you 68/70Vette, you have been very helpfull. I'll torque the bolts and move on. Thanks again.