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Can the improper installation of the timing belt cause the pulley bearings to fail?


I'd say no.

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Are the pulleys usually replaced with a timing belt if the pulley bearings are sealed?


I'd say if you asked for it, yes. If you didn't ask for it, probably not.

Joe

A gun in the hand is better than a cop on the phone.

98 Passport 33's, Supercharged, Calmini Bumper, rockbars, diff drops, Teralows, 4.77's, Aussie and ARB lockers, Safari snorkel, Optima red top.