Supersonic 427

Dealer Tech found no leaks in all the hydraulic cylinders, pump and hoses. He also called a GM service Tech and was advised to replace the cylinder on the drivers side tonneau cover.
Trouble is the part will take about a week to come in! So, going to return the rental and pick up the Vette tomorrow morning. They will call me when the part comes in for installation. Thanks to all and especially "gve" who nailed the problem in his post!

Always Red Dave

Good luck Gary and hope you get the part sooner and fixed properly!

Supersonic 427

Thanks Dave! I hope so!

gve

I'm glad you didn't have leaking fluid in your car, could be an internal leak in the cylinder. After they replace the cylinder let us know if it corrects the problem. At least you can still drive your car, and it's not that warm yet to put the top down.

owc6

Supersonic 427, gve's comment made me wonder; if your top is up, does your tonneau pop up, or does the weight/tension of the closed top keep the tonneau down? The tonneau is in the exact same position whether up or down.

Supersonic 427

The tonneau cover is perfectly flush with the top up. It only pops up when the top is down.

Supersonic 427

Yes, glad there were no leaks anywhere. I hope the new cylinder fixes the problem and I agree it must be an internal leak in that cylinder where it is losing pressure. Thanks for your help with the diagnosis...you nailed it!

Foosh

Interesting . . . I would guess it's the bunched up folded top pushing it back up if the hydraulic cylinder is not holding pressure. I can't imagine it's pressurized with top down and not with the top up, since it's in the same position. The hydraulic pressure should be constant when the tonneau is in the down position, top up or down.

Lisa could be right that the top in the up position is holding it down.

Supersonic 427

I think it is the pressure of the cylinders in the rear of the convertible top holding the tonneau cover flush when the top is up. I think Lisa is right!