Ford Full-Size Cars 1968-1988 Repair Guide

Rocker Studs



Rocker arm studs which are broken or have damaged threads may be replaced with standard studs. Studs which are loose in the cylinder head must be replaced with oversize studs which are available from most automotive parts stores. Refer to a local machine shop if necessary. The amount of oversize and diameter of the studs are as follows:

0.006 in. (0.152mm) oversize: 0.3774-0.3781 in. (9.586-9.604mm)
0.010 in. (0.254mm) oversize: 0.3814-0.3821 in. (9.688-9.705mm)
0.015 in. (0.381mm) oversize: 0.3864-0.3871 in. (9.815-9.832mm)

A tool kit for replacing the rocker studs is available and contains a stud remover and two oversize reamers: one for 0.006 in. (0.152mm) and one for 0.015 in. (0.381mm) oversize studs. For 0.010 in. (0.254mm) oversize studs, use reamer tool T66P-6A527-B. To press the replacement studs into the cylinder head, use the stud replacer tool T69P-6049-D. Use the smaller reamer tool first when boring the hole for oversize studs.

  1. Remove the valve/rocker cover(s). Position the sleeve of the rocker arm stud remover over the stud with the bearing end down.

An alternate method of removing the rocker studs without the special tool is to put spacers over the stud until just enough threads are left showing at the top so a nut can be screwed onto the top of the rocker arm stud. Turn the nut clockwise until the stud is removed, adding spacers under the nut as necessary.

If the rocker stud was broken off flush with the stud boss, use a screw extractor to remove the broken part of the stud from the cylinder head.

  1. If a loose rocker arm stud is being replaced, ream the stud bore for the selected oversize stud.

Keep all metal particles away from the valves.

  1. Coat the end of the stud with Lubriplate® or equivalent. Align the stud and installer with the stud bore and tap the sliding driver until it bottoms. When the installer contacts the stud boss, the stud is installed to its correct height.