WIPER ARM

618 078 49 WIPER ARM is the business end of your windshield wiper system, really. It's what actually holds the blade and transfers the motion from the wiper motor linkage to sweep across the glass. Without it, or if it's not doing its job right, you're not clearing anything. It's got a spring mechanism inside that keeps constant pressure on the blade, pushing it down onto the window so it can actually wipe away the muck, dust, or rain you're constantly dealing with on site.

When this arm starts to give up the ghost, you'll usually notice it pretty quick. The most common thing is the blade not making full contact, leaving streaks or unwiped sections, especially in the middle of the sweep. Sometimes the spring tension goes weak, and the blade just sort of skitters across the glass instead of wiping cleanly. You might also hear a chattering noise from the blade, or the whole arm might feel loose at its pivot point, causing the blade to lift off the glass at speed or during heavy rain. It's a real visibility killer when it's failing.

Replacing one of these isn't rocket science, but there are a couple of things to watch for. Always check the splines on the wiper motor shaft where the arm attaches; if they're worn down, a new arm won't seat properly and you'll just strip it out again. Also, take a good look at the wiper blade itself. Often, a failing arm has been fighting a worn-out blade, so it's a good idea to swap both at the same time. Don't forget to give the pivot points a quick check for any binding or excessive play too, while you're in there.