Several options: 1#, replace the drawer guides with full metal ones. 2#, use washer head screws on the replacement plastic supports to reduce breakage. 3#, add wood shims (+ longer screws) behind the supports so the track fully seats on the support for less vertical stress. 2# and 3# worked for me.
The factory likes to use phillips head screws intended for counter-sinking and these crack the plastic support. Also, while the supports are designed so that the track doesn't have to fit completely against the back of the support, having a large gap allows the drawer and support to sag and flex which doesn't work well for a house on wheels.
Texas Baptist Men-Retiree Builders member since '01
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