Design, materials improve durability
As components, they may be relatively small, but in terms of the havoc wheel seals can wreak when things go awry, the stakes are big. A leaky seal that leads to soaked brake linings, for example, has the potential to create serious - and expensive - maintenance problems. Here's how manufacturers are responding.
Chicago Rawhide offers a long-life version of its original Scotseal that's geared to withstand the tougher operating environment created by synthetic lubricants. Made from a hydrogenated nitrile material with a higher temperature capability, it's more compatible with the harsh additive packages found in synthetic lubes.
Federal-Mogul's National 5-Star Gold Teflon wheel seal is designed to address excessive wheel-end movement and loose bearing adjustment. The seal features a Teflon "lay down" lip with enough contact area to absorb wheel-end movement and floating dirt excluder.
Freudenberg-NOK's Outrunner is a premium oil-bath wheel seal designed to meet the performance demands of low-maintenance wheel ends. The seal lip withstands extremely high temperature; a labyrinth design keeps the wheel end free of dust and grime; bi-directional helixes continuously pump oil away from the primary sealing lip. Pre-lube grease protects against dry-start wear, and unitized construction makes installation easier. Outrunner seals, which are manufactured at the company's new Northfield, N.H., plant, are compatible with synthetic, mineral, or semi-fluid lubes.
Meritor offers a hub-installed, unitized version of its one-piece MVP oil-bath wheel seal. As part of a unitized wheel-end system, the seal doesn't have to be installed separately, thus eliminating a major cause of seal leaks. A graphite-loaded rubber compound and large vent holes protect the wheel from high brake temperatures. Meritor also offers a two-piece seal, the MVP-2.
Stemco's Guardian HP seal, a semi-unitized, spindle-installed unit, features a high-performance sealing lip. The Voyager, which has double-case steel construction for improved durability, is characterized as a cost-efficient, hub-installed unitized seal. Stemco's premium seal, Discover, also has a hub-installed, unitized design, as well as an anti-rotation feature that locks the seal to the spindle and makes installation easier.