Replacing a Sliding Glass Window in 75 series Troopy

The main surprise in this process is just how easy it is! The window assembly is held in place by an internal cover strip (the “Window Guard”) that is a plastic moulding with a C cross-section profile. Although this appears to be little more than cosmetic, it is this C section that actually secures the whole window to the vehicle. A bead of butyl material between the window assembly and the vehicle panel helps too and provides dust proofing, but it is this plastic moulding that holds it all together.

There are different window assemblies, but my interest was in the sliding glass type. This diagram from the maintenance manual shows both fixed panels and sliding configurations.

Removing the window assembly from the vehicle simply requires working inside the vehicle, removing the C section moulding (Window Guard), and (if necessary), cutting the butyl mastic material which is sandwiched inside that moulding between the window sash and the vehicle. It pays to have an assistant waiting outside to catch the window when the window guard is removed. (The mastic provides little support and the window could easily leave the vehicle unexpectedly. Each piece of glass costs about $160 !) The old mastic should be removed by scraping followed by a petrol soaked rag to remove the last of it.

Disassembling requires that the centre strip be unscrewed, the glass panels be roughly centred in the opening and the sash stretched as shown here. Two people are required, one to stretch the frame (requires quite some effort), the other to handle the glass. The centre weather strip can be removed once at least one pane of glass has been removed.

Reassembly is simply a reversal of the above, with a new and generous bead of Selley’s D-Mastic or similar caulking compound applied to the join between sash and vehicle body and the Window Guard moulding forced fully into place.