In addition to common installation errors, there are four conditions to look for when inspecting a Scotseal Plus failure:

• Improper installation (Tools are not an issue, but O.D. or I.D. not lubed is)
• Cocked installation
• Improper bearing adjustment
• Spindle not fully cleaned (The Scotseal Plus has a wide footprint that requires a larger area of the spindle be clean and free of rust and contamination)

Seal designs are most often represented by a flat view of the seal cut crosswise, like the one shown here. Only the top cross section is used.

The shaft, or in this case axle spindle, is represented by the base line. The wheel hub is indicated at the top. A Scotseal Plus has a rubber O.D. and I.D. that must be lubricated before installation. The seal is installed first into the hub and then mounted on the spindle.

In this illustration, the bearing side (or oil side) is to the left and the outside (or air side) is to the right.

The main components of the seal are:

(A.) Rubber O.D. and beads
(B.) The seal section
(C.) The flange and
(D.) The rubber I.D. and beads

The sealing elements are:

(A.) The bumper lip
(B.) The axial dirt lip
(C.) The radial dirt lip and
(D.) The primary sealing lip

The Scotseal Plus is a unitized seal, which means all of the sealing surfaces are protected inside the seal. The four sealing surfaces rotate with the hub and wheel, while the flat sealing surface remains stationary on the spindle.

The fact that the Scotseal Plus has four sealing points makes it a very effective seal at keeping out dirt and other contaminants.