Hello,
Am having a problem with the soft top on a W124 E320 where it gets stuck during the bow section portion of the operation. When either opening or closing the top everything works fine until it's time to lift the bow section then it stops. Have tried many solutions to fix the problem with no success.

Opening the top: unlatch the locks and push top up...pull back on the button and the bow lock releases but the bow does not go up...get out of the car and manually lift the bow section all the way up...back in the car and continue the operation...tonneau lifts up as it should but bow section fails to move back down into the roof storage area so again get out of the car and pull down on the bow section...back in the car and continue the operation with bow section dropping into the storage area and the main top section lifts and also tucks back into the storage section...tonneau comes down and locks shut.
Closing the top: same situation...tonneau opens up, main top extends out completely but bow section does not go up...get out and manually lift the bow section up...back in the car to continue the operation with tonneau closing but again the bow section does not go down so again manually lower it then it locks down.

I had another E320 with a properly working top so was able to swap out many components to test if there was a bad component causing the problem, but nothing solved the issue.
Components swapped: ECU, pump, both bow cylinders, tonneau lock cylinder

None of the cylinders are leaking externally.
Tested every micro switch with a meter and all are working correctly.
Removed the hydraulic line from both bow cylinders and attached them to a clear tube to check if fluid was coming out during the open/close procedure...and both had fluid coming out.
And finally, I confirmed that all the numbered hydraulic lines were all correctly going from the valve blocks to the corresponding cylinders.

It could be an internal bypass leak but not sure where this leak is to cause this problem?