Measure the amount of free play at the clutch pedal.
Use a ruler to obtain an accurate reading, and compare it
against specifications. If the specifications are not avail-
able, between 1″ and 1.5″ (25 mm and 38 mm) of free play
is generally acceptable.
Before adjusting free play, check the master cylinder
reservoir to make sure the fluid level is sufficient. Add
DOT 3 brake fluid if necessary.
Caution: Never add motor oil, transmission
fluid, or any kind of petroleum-based oil to
the master cylinder reservoir. Use brake
fluid only to prevent major damage to seals!
Loosen the locknut holding the threaded rod to the
adjuster. Turn the rod until you obtain the proper free play
as measured at the clutch pedal. Retighten the locknut.
Recheck the free play at the clutch pedal. Then, road test
the car.
Clutch Linkage Repair and Replacement
Check the clutch linkage for proper operation. One of
the most common points of wear in the linkage is the pedal
itself. Bushings can wear, or the mounting bracket bolts
can loosen. Always check these parts when servicing the
clutch linkage or overhauling a clutch. Figure 7-10 shows
typical clutch pedal components.
Rod-and-lever linkage
A rod-and-lever linkage usually wears at pivot points.
See Figure 7-11. Many pivot points contain metal or plastic
bushings. These bushings often wear out.
Sometimes, linkage rods or levers will bend. This
may happen if something in the clutch causes excessive
resistance in disengagement. Another common cause of
problems is a bellcrank that binds or is loose because of
worn motor mounts or misalignment of the engine in the
vehicle. The linkage must be restored to perfect operating
condition before the clutch will operate properly. This
may involve lubrication, adjustment, or replacement of
linkage parts.
Cable linkage
Cable linkage problems are usually due to a seized or
binding cable assembly. Cables can seize due to corrosion
or lack of lubrication. A cable may seize or bind if it is
caused to kink in its sheath from improper routing.
Defective cables should be replaced.
If a cable must be replaced, make sure you route it so
there is no possibility of seizing or binding. Use all the
original cable brackets and mounting locations if possible.
A typical cable arrangement is shown in Figure 7-12.
Hydraulic linkage
Before adjusting a hydraulic linkage, always check
the fluid level in the master cylinder reservoir first. If the
fluid level is low, check for leaks at the places indicated in
Figure 7-13. Leaks appear as dark stains on hydraulic sys-
tem parts. Sometimes the brake fluid used in the system is
visible at the point of the leak. Leaks can occur in the
hydraulic lines or at loose connections. The most common
leaks, however, occur at the master or slave cylinder seals.
It is usually easier and cheaper to replace leaking
master and slave cylinders. However, in some cases, a
134 Manual Drive Trains and Axles
Stop screw
Pedal
support
bracket
Bushing
Bushing
Clutch
pedal and
pivot shaft
Pivot shaft
locknut
Clutch
cable
lever
Bushing
Brake pedal
Figure 7-10. Study the exploded view of a typical clutch and
brake pedal assembly. The pivot points should be carefully
checked and lubricated. (DaimlerChrysler)
Clutch
linkage rod
Lever
arm
Forward
Clutch
rod
Clutch pushrod
Clutch
fork
Bellcrank
Clutch
pedal arm
Figure 7-11. Notice the pivot points in this exploded view of a
rod-and-lever linkage. Most problems in this system are caused
by wear, misadjustment, or lack of lubrication at the pivot
points. (General Motors)