Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.
Request an inspection using the correct wear-check procedure and limits for the installed suspension. Base replacement on documented condition rather than the other vehicles' mileages.
Source: This question and its visible discussion. The roadmap distinguishes the original owner's reports from other participants' experiences; proposed follow-up is editorial guidance, not a confirmed diagnosis. MOOG: Ball joint inspection procedure https://www.moogparts.com/content/dam/marketing/North-America/moog/pdf/did-you-know/english/DYK09_103_En.pdf Dodge-van example illustrating why inspection depends on joint design; its procedure and limits are not F-150 specifications.
Ball joint replacement around 85,000–87,000 miles is typical on a similar 1998 F-150. When replacing, use lifetime-warranty ball joints or joints with grease fittings so the parts do not have to be paid for again.
The owner of a 1998 F-150 with 85,000 miles asked when front ball joints and tie rods normally wear out under ordinary driving. Other owners reported upper ball joint replacement at about 101,000 miles on a 2000 Expedition and both upper and lower ball joints at 120,000 miles on a 1997 Explorer, and noted that wear depends on driving and maintenance. An expert who replaced ball joints on a similar 1998 F-150 about 2,000 miles later said that timing is typical and recommended lifetime-warranty parts or joints with grease fittings.
F150 Ball Joints
The owner of a 1998 F-150 with 85,000 miles asked when ball joints and tie rods should normally need replacement. Replies offered replacement mileages from several trucks and SUVs.
Reported outcome: No inspection findings or replacement on this truck were reported.
Anecdotal replacement mileages do not establish a service interval or demonstrate that these parts were worn.
