From the November 2000 issue.

When you install replacement brake linings, is there a change in braking performance? Do you have any assurance that the friction level of the replacement
lining is the same or equal to the old one? If you answered “yes” to the first
question and “no” to the last, you probably buy whatever the parts shop chooses to sell you.

Not good enough.

First lesson in Brakes 101: match linings in terms of their friction ratings and
torque capabilities.

Unmatched linings are one of the main contributors to brake-system balance
problems. And imbalanced brakes can cause serious instability on the road, not
to mention poor lining life. The point is that the brake at each wheel position is not
working alone but as part of a “team,” and if you don’t match friction levels, you
may find yourself with one corner or one axle of the rig being more (or less)
aggressive than the others. Presto! You’ve created imbalance right out of the box.

Think of your brakes as a system. If part of the system isn’t right, the whole system
isn’t right.

Yes, it’s smart to replace both shoes and linings on the brake assembly of a brake
that’s worn or soaked with oil, for example. But you should also replace the shoes
and linings on the other end of the axle, regardless of their condition.

Otherwise, the brake that hasn’t been relined will do more work, creating
imbalance and accelerated brake wear.

“Plumbing” imperfections can also tip your system’s balance, perhaps sending
too little air too slowly to one brake or axle. If other brakes are overstressed, their linings will wear faster. Replace your brake valves with another of exactly the same rating.