File 02: A Living Room Slide That Came Back Out of Square

A 36 foot bunkhouse fifth wheel, six model years old, with a twelve foot living room slide driven by a Schwintek in wall system. Twelve feet is at the upper end of what that drive is comfortable with, especially on a room carrying a sofa and part of a kitchen wall, and that fact is relevant to everything that follows.

We cycled the room on level and measured the leading edge at both top corners at three points through travel. The rear corner was running roughly five eighths of an inch behind the front by the end of travel. Anything past a quarter inch will chew a wiper seal, so the seal damage the owner had noticed was a symptom rather than a cause. The contact damage itself was a scuff and a crease at the corner.

The room came out onto stands, which is the only way to see a Schwintek rail along the section that carries load. The difference between the two sides was not subtle. The front rail had a bright wear band and a floor of metallic dust beneath it; the rear rail was comparatively clean. On the front gear pack, three tooth crowns had rounded over to the point where engagement was shallow.

That pattern reads in one direction only. A clean side is a side that has not been doing the work, which means the other side has been carrying the room, which means the room has been running slightly out of sync for a considerable time. The storage lot contact did not cause that. What it did was push the geometry far enough past tolerance that the seal finally failed and the owner noticed.

With the room out, the leading edge of the slide floor read damp on a pin meter over a section about thirty inches wide. The chewed wiper seal had been letting water past for long enough to wet the decking edge, and the material had begun to delaminate at the plies. This was not visible with the room installed and it was not in the original estimate.

It also had to be dealt with then or never, because the only time that edge is accessible is with the room on stands. So a section of decking was cut out and replaced, the edge was sealed, and the new wiper seal went on against sound material. Adding it cost eight hours. Deferring it would have meant a second room removal within two years, which is a great deal more than eight hours.

The carrier covered the contact damage: the corner post crack, the scuff and crease, the refinish on the affected panel. They declined the rail and gear pack replacement, and they were right to. Rail wear across a season of cycles is deterioration, not a loss event, and no amount of arguing changes that. We did not try, and we told the owner the answer before the file was submitted.

What the documentation did achieve was a clean split. The measurement record showed the asymmetric wear pattern and the dust distribution, which established that the wear predated the contact rather than resulting from it. That kept the covered portion clean and it kept the declined portion from being disputed later. Owners generally prefer a clear line to an optimistic one.

Fifty three labor hours: forty one in the mechanical and electrical department at $260 per hour and twelve body hours at $210 for the corner post and refinish. Nineteen shop days, of which eleven were a rail on allocation from Lippert. On delivery the room measured within an eighth of an inch at both corners on the first, fifth and tenth cycle.

The habit worth taking from this file is levelling. A twelve foot room run repeatedly on an unlevel pad loads one rail far harder than the other, which is exactly the asymmetric wear we found. The second habit is stopping when a room starts to sound different. Neither costs anything, and together they are most of the difference between a seal job and a rail job.