Sephia LS Sedan L4-1.8L (1998)
Brake Pad: All Technical Service Bulletins
Brake System - Pad Wear Diagnosis
SOURCE: Kia Technician Times
TITLE: Brake Pad Wear Diagnosis
APPLIES TO: Sephia/Spectra
SERVICE TIP:
There is more to addressing brake pad wear issues than just replacing pads. When you have a customer that goes through pads every 5,000 miles or less,
there is something wrong either with the vehicle or with the customer's driving habits.
The current brake pads and system used in 98-00 Sephia models was tested by an outside engineering company. The test was the L.A. City Traffic Test,
a severe stop & go brake test that most auto manufacturers use to determine a minimum expected brake pad life in severe service. The results of this test
on the Sephia showed a minimum pad life of 9,300 miles.
When you have a vehicle with excessive low mileage pad wear, the following items should be checked:
1. Brake pedal pushrod freeplay adjustment
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Check for freeplay at brake pedal. There must be a minimum of 0.160" (4mm) pedal freeplay before booster resistance is felt. (Check with
engine off, booster vacuum depleted.)
2. Caliper freedom of movement
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Check for free movement of caliper on slides and pins.
a. Push caliper piston back into caliper.
b. With pads installed in caliper, remount caliper to spindle.
c. Move caliper back and forth by hand - it should slide smoothly on slides and pins. If it does not, clean and lubricate sliding surfaces and
pins with a good high temperature caliper grease.
3. Brake booster pushrod adjustment
Note: Misadjusted booster pushrods are uncommon, but should always be checked in cases of premature pad wear.
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Check booster pushrod adjustment. A quick method of checking for adequate pushrod clearance is:
a. With engine off, depress brake pedal several times to deplete vacuum in booster.
b. Rotate front wheels by hand and note drag.
c. Start engine, and again rotate front wheels by hand, and note drag. If there is no difference in rotating drag between vacuum depleted
booster and vacuum charged booster, the booster-pushrod adjustment is okay. If rotating drag increases with vacuum charged booster
(engine running), the booster pushrod is out of adjustment.
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If the booster pushrod check indicates pushrod is out of adjustment, booster/master cylinder assembly should be replaced.
Note: Rear brake adjustment is often condemned as the cause of excessive pad wear. However, this is not the case. The Sephia/Spectra rear brake
self-adjusters operate on a series of notches. The typical operating range between full release of shoes and full adjustment is seven notches. When the
brake pedal is depressed, the adjuster moves to the first or second full adjustment notch. At this position, the shoe to drum clearance is ~0.001". When
in this self-adjusted position, there should be little or no brake shoe drag when brake drum is rotated.
The only effect rear brake adjustment has on brake operation is pedal height.
