J-Tube Block-Off Plate Stud Damage - TSRM Torque Spec Error (89 vs 9 ft/lbs)

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Problem

After installing a J-tube block-off plate, the plate leaked. Overtightening the studs caused them to bend and the stud threads to strip. The Toyota Service Repair Manual (TSRM) lists an incorrect torque spec of 89 ft/lbs for the J-tube studs, when the correct spec is only 9 ft/lbs (13 Nm).

Coolant or air leak at J-tube block-off plateBent J-tube studs after tighteningStripped threads on the studs themselvesStuds pulling out of the block feeling like a rusted-on nut

Root Cause

The TSRM (both 1990 and 1992 editions) incorrectly lists the J-tube stud torque spec as 89 ft/lbs instead of the correct 9 ft/lbs (13 Nm). Overtightening to anywhere near the erroneous spec bends and strips the small M8 studs. Even hand-tightening without a torque wrench can be inconsistent and cause leaks if not properly sealed.

Confidence

High confidence — Multiple community members agreed on this solution

View Original Thread →Posted August 2022 on SupraForums.com