Originally Posted by onehundred80

The pneumatic locking system has been a problem for years, the pump in the trunk gets wet from leaks, the yellow vinyl hose breaks at the flex points which are in the rubber conduits at the bottom of the doors and at the top of the hatch. The yellow vinyl hose is replaced by urethane hose. It is impossible to remove all of the yellow hose as it is incorporated in the wire loom. Just replace the flexible length of hose with urethane hose with a hose with an inside diameter which is a tight fit on the outside diameter of the yellow hose and the urethane hose, do not use vinyl hose, or use a barbed 5/16” outside diameter straight fitting.
When a yellow hose breaks you can hear the hissing, Generally only a portion of the locking system fails, but the car will remain open or closed in that portion of the system. I replaced the whole line from the hatch lock to the pump with blue urethane hose when I fitted a backing up camera. The hose is 5/16” inside diameter. You could use 1/4” inside diameter hose if you heated the end up and stretched it to 5/16”, I tried it and it worked fine on one little job.