I replaced the broken nylon window guides on the big front window after I fixed the rivet problem and put on new weather stripping. See the thread:
I made sure the the guides went in at the same location (I marked the top edge of the old guide on the frame and matched them up on both sides that way).
The problem is that they don't seem to want to hold the window operator in place. The left side is quite prone to slipping out and then the right side follows suit soon after. This is sitting the the garage so there isn't any wind to speak of.
I did notice that the guide flexes a little bit under the stress of the window which is probably what is causing the problem. Also the guides are quite slippery compared to the old ones. The other potential problem is that the left and right guides may not be exactly the same so that the one side (left) is a bit higher now, if it is it isn't by any significant amount and the window flex seems to mask it.
Has anyone else had this problem? Is this a common problem with the very heavy front window (the old guides were broken so we never used it)? Any suggestions?