On my '73 450SLC I've had problems getting the rear side windows to operate - they tend to jam about half way down. They've had a pretty hard life and I don't believe they've been re-lubricated since birth. So, inevitably, they were worked pretty hard and have been slightly bent. However, even after many attempts to straighten them back to original and trying different types of lubrication they still weren't working reliably. About half way down the whole mechanism would bind and start bending. The geometry of the arms just didn't seem right and I managed to get an acceptable result by re-drilling and re-positioning the slides but it still wasn't "right".
In desperation I managed to source a replacement set from a more recent 450SLC. These replacements had quite different geometry as seen by the photos below. The arms of the mechanism are different lengths and angles are different. The vertical slide is now made from straight steel rather than curved aluminium. And, the bottom line, they work first time, every time. So there was obviously a design fault in the early mechanisms that made them marginal and this has been fixed in later versions.
In these photos the old mechanism (with the extra brace) is on the right. The seemingly lighter new mechanism is on the left. For the vertical guide, the older guide is at the rear (made of aluminium and curved).
![Image]()
![Image]()
![Image]()
Hope this helps someone
Cheers
Pete
In desperation I managed to source a replacement set from a more recent 450SLC. These replacements had quite different geometry as seen by the photos below. The arms of the mechanism are different lengths and angles are different. The vertical slide is now made from straight steel rather than curved aluminium. And, the bottom line, they work first time, every time. So there was obviously a design fault in the early mechanisms that made them marginal and this has been fixed in later versions.
In these photos the old mechanism (with the extra brace) is on the right. The seemingly lighter new mechanism is on the left. For the vertical guide, the older guide is at the rear (made of aluminium and curved).
Hope this helps someone
Cheers
Pete
