Pinpoint Test D: Clutch Drag, Also Hard to Shift
Manual Transmission and Clutch
Pinpoint Tests
Pinpoint Test D: Clutch Drag, Also Hard to Shift
Normal Operation
The clutch is designed to transfer the power from the engine to the transmission, which may be either stationary (starting) or rotating at a different speed (upshifting or downshifting). The clutch is functioning correctly when both the engine and transmission are rotating at the same speed with the clutch engaged. Clutch pedal movement is transmitted by fluid pressure, which actuates the clutch release hub and bearing. The clutch release hub and bearing pushes on the spring center towards the flywheel. The diaphragm spring pivots at the fulcrum, relieving the load on the clutch pressure plate. Steel spring straps riveted in the clutch pressure plate cover pull the clutch pressure plate from the clutch disc, disengaging the engine torque from the transmission.
This pinpoint test is intended to diagnose the following:
- Internal operation
- Clutch pedal reserve
- Clutch slave cylinder travel
- Clutch disc
- Clutch pressure plate
- Clutch pedal free play
PINPOINT TEST D: CLUTCH DRAG, ALSO HARD TO SHIFT
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D1 CHECK FLUID LEVEL
- Ignition OFF.
- Remove the reservoir cap and reservoir diaphragm.
- Inspect the fluid level in the clutch master cylinder reservoir.
- Is the fluid level at or above the step mark?
Yes
INSTALL the reservoir cap and diaphragm. GO to D2.
No
ADD brake fluid. GO to D2 and CHECK for leaks. TEST the system for normal operation.
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D2 INSPECT THE CLUTCH HYDRAULIC SYSTEM FOR LEAKAGE
- Inspect the clutch master cylinder and the hydraulic tubes for leakage.
- Inspect the reservoir and reservoir tube for leakage.
- Inspect the clutch slave cylinder and the hydraulic tube connection for leakage.
- Are there any signs of leakage?
Yes
INSTALL new components as necessary. REFER to Clutch, M/T. TEST the system for normal operation.
No
GO to D3.
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D3 CHECK INTERNAL OPERATION
- Remove the reservoir cap and reservoir diaphragm.
- Have an assistant slowly depress and release the clutch pedal.
- On the down stroke, the fluid level should not increase by more than 1 mm (0.039 in).
- Does the fluid level increase more than 1 mm (0.039 in)?
Yes
INSTALL a new clutch master cylinder assembly. REFER to Clutch, M/T.
No
GO to D4.
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D4 CHECK THE CLUTCH PEDAL RESERVE
NOTE: The clutch reserve is the distance between the clutch pedal when fully depressed and the position when the vehicle starts to move forward.
- Park the vehicle on a level surface.
- Check for obstructions behind clutch pedal.
- Attach a cable tie to the lower clutch pedal.
- Attach a tape measure to the cable tie.
- Depress the clutch fully and start the vehicle.
- Shift the transmission into 1st gear.
- While observing the tape measure, slowly engage the clutch, noting when the vehicle starts to move forward.
- Is the clutch pedal reserve greater than or equal to 25 mm (1 in)?
Yes
The clutch hydraulic system is OK. TEST the system for normal operation.
No
GO to D5.
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D5 CHECK CLUTCH PEDAL FREE PLAY
NOTE: The clutch pedal free play is the distance between the clutch pedal when fully released and the position when slight resistance is felt on downward motion.
- Engine OFF.
- Attach a tape measure to the cable tie.
- While observing the tape measure, slowly push downward on the clutch pedal until a slight resistance is felt.
- Is the clutch pedal free play less than 13 mm (0.5 in)?
Yes
The clutch hydraulic system is OK. TEST the system for normal operation.
No
GO to D6.
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D6 CHECK CLUTCH PEDAL FREE PLAY WITH THE CLUTCH SLAVE CYLINDER DISCONNECTED
NOTICE: Do not bleed clutch hydraulic system.
- With the vehicle in NEUTRAL, position it on a hoist. Refer to Vehicle Jacking and Lifting.
- Clean the area around the connector. Using the Hydraulic Line Disconnect Tool, disconnect the hydraulic tube from the clutch slave cylinder.
- Lower the vehicle.
- Check the clutch pedal free play.
- Attach a tape measure to the cable tie.
- While observing the tape measure, slowly push downward on the clutch pedal until a slight resistance is felt.
- Is the clutch pedal free play less than 13 mm (0.5 in)?
Yes
RECONNECT the hydraulic tube to the clutch slave cylinder. GO to D7.
No
INSTALL a new clutch master cylinder. REFER to Clutch, M/T. DEPRESS and RELEASE the clutch pedal 15 full strokes. Clutch pedal should feel firm. RECHECK clutch pedal free play. If free play is greater than 13 mm (0.5 in), GO to D7.
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D7 BLEED THE CLUTCH SLAVE CYLINDER
- Remove the clutch reservoir cap and diaphragm. Check the fluid level. Fill the reservoir to or above the step mark. Install the cap and diaphragm.
- Depress and release the clutch pedal several times to stabilize the clutch hydraulic system.
- With the vehicle in NEUTRAL, position it on a hoist. Refer to Vehicle Jacking and Lifting.
- Remove the bleeder screw cover and attach a vinyl hose to the bleeder hose. Place the other end of the vinyl hose into a clear container partially filled with brake fluid.
- Have an assistant depress and release the clutch pedal 5 times, then hold the clutch pedal down. With the clutch pedal depressed, loosen the bleeder screw to let air escape the clutch system. Tighten the bleeder screw. Repeat this process until no air comes through the vinyl hose.
- Tighten the bleeder screw and install the bleeder screw cover.
- Slowly pump the clutch pedal several times to verify there is no fluid leakage.
- Depress and release the clutch pedal 2 short cycles and 3 full-travel cycles.
- Make sure the clutch reservoir is at the correct level. Refill as necessary.
- Is the clutch pedal reserve greater than or equal to 25 mm (1 in) and is the clutch pedal free play less than 13 mm (0.5 in)?
Yes
The clutch hydraulic system is OK. TEST the system for normal operation.
No
GO to D8.
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D8 CHECK THE CLUTCH PRESSURE PLATE
- Remove the clutch pressure plate. Refer to Clutch, M/T.
- Inspect the clutch pressure plate for wear or runout. Refer to Clutch Pressure Plate Check Procedures.
- Are there any signs of excessive wear or runout to the clutch pressure plate?
Yes
INSTALL a new clutch pressure plate. REFER to Clutch, M/T.
No
GO to D9.
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D9 INSPECT THE CLUTCH DISC
- Carry out the clutch disc inspection procedure.
- Is the clutch disc OK?
Yes
VERIFY the customer concern. GO to Symptom Chart - Clutch Operation if necessary. Symptom Chart - Clutch Operation
No
INSTALL a new clutch disc. REFER to Clutch, M/T. TEST the system for normal operation.
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