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How to Diagnose Clutch Drag and Adjust Your Clutch Pedal

Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology.

If you fully depress the clutch pedal but the clutch disc doesn't disengage completely, the clutch will drag.

Clutch drag symptoms may include:

  • Hard starting
  • Vehicle movement during starting
  • Hard shifting
  • Hard shifting in high rpm
  • Gear clash during shifting

There could be one or more reasons why your clutch is dragging. Some of these are more common than others.

What causes clutch drag:

  • Too much clutch pedal free play
  • Maladjusted clutch master cylinder
  • Hydraulic system air pockets
  • Pressure plate warped (from overheating)
  • Flywheel warped
  • Damaged clutch disc
  • Clutch linkage problems
  • Clutch assembly issues

The next sections will help you diagnose the problem and, if possible, fix clutch drag.

Index

I. How to Check for Clutch Drag

II. How to Fix Clutch Drag

III. Clutch Pedal Play and Adjustment

1. Checking Clutch Pedal Free Play

2. Adjusting the Clutch Linkage

3. Adjusting the Clutch Cable

4. Adjusting a Hydraulic Clutch Mechanism

IV. Checking the Clutch Linkage

V. Clutch Assembly Problems

VI. Should You Be Worried About Your Clutch Drag

When your clutch drags, shifting gears may cause a grinding noise.

When your clutch drags, shifting gears may cause a grinding noise.

I. How to Check for Clutch Drag

This is a simple test. Still, make sure you have enough space in front and back of the vehicle in case the car creeps forward or backward during your test. Specially, check that there's no one standing in front or back of the car.

  1. Set the transmission to neutral.
  2. Start the engine.
  3. Fully depress the clutch pedal.
  4. Shift the transmission into first gear and keep the clutch pedal fully depressed.
  5. Shift the transmission into neutral.
  6. Wait 5 seconds to allow the transmission to come to a complete stop.
  7. Without forcing the shift lever, shift into reverse.

If you can hear the gear clash, the clutch is dragging.

Incorrect clutch pedal free play is the most common cause of clutch drag.

Incorrect clutch pedal free play is the most common cause of clutch drag.

II. How to Fix Clutch Drag

By far, the most common problem behind clutch drag is incorrect clutch pedal adjustment, but it's not the only source of trouble. Here are some common and not so common problems:

  • Clutch pedal free play
  • Faulty clutch linkage
  • Clutch assembly problems

The next two sections give you a rundown of the process to check and adjust clutch pedal play, checking the clutch linkage and assembly that can help you fix the problem.

III. Clutch Pedal Play and Adjustment

Too little clutch pedal play leads to clutch slip, but too much clutch pedal play can lead to clutch drag. If your clutch system doesn't automatically adjust, or there's an issue with your clutch linkage in an automatic adjusting system, you may find and, possibly, fix the problem.

On a manually adjustable clutch linkage, the release bearing should have some clearance to keep it from touching the pressure plate release levers when the clutch is engaged (the clutch pedal is up). Clearance prevents accelerated wear of these components.

When this clearance shortens (as clutch disc wears), you can manually adjust the clutch linkage to prevent or fix clutch drag, if the clutch disc still has enough lining. You can do this by adjusting clutch pedal play.

The next steps present a general procedure and may not apply exactly to your particular application, but they'll give you an idea of how to adjust a clutch linkage. Consult the vehicle repair manual for your particular vehicle make and model as necessary.

Use a regular tape measure or ruler to check clutch pedal free play.

Use a regular tape measure or ruler to check clutch pedal free play.

1. Checking Clutch Pedal Free Play

Keep in mind that on some vehicles with a mechanical clutch linkage, the manufacturer suggest measuring clutch linkage clearance from under the vehicle or under the hood, depending on your particular model. And even methods of measuring clearance may change from one model to the next. So make sure to consult your vehicle repair manual for the recommended procedure for your particular model.

  1. Place a tape measure or ruler next to the clutch pedal, with one end of the tape or ruler against the floor of the vehicle, toward clutch pedal movement.
  2. Write down clutch pedal distance from the floorboard of your car.
  3. Without moving the tape measure or ruler, push down the clutch pedal with your free hand just to take up clutch pedal free movement.
  4. Write down the new clutch pedal distance from the floor.
  5. Subtract the last measurement from the first one. This is your clutch pedal free play.

Compare your clutch pedal play measurement with the specification in your vehicle repair manual.

2. Adjusting the Clutch Linkage

  • Locate the adjustment points. You can find them in your vehicle repair manual. These may be:

    • Under the vehicle
    • Under the hood
    • Bottom end of the clutch cable
    • Under the dashboard
  • When adjusting, you'll need to turn a nut or similar threaded fastener at the clutch pedal or at the linkage, where it joins the clutch operating lever next to the transmission or transaxle.
  • On a mechanical clutch linkage, the adjustment is usually at the push rod connected to the clutch fork. Look for the rod's threaded end.
  • Loosen the push rod nuts.
  • To decrease free travel (raise clutch pedal), increase the rod effective length.
  • To increase free travel (lower clutch pedal, shorten the rod effective length.
  • If necessary, remove dirt or grime from the linkage mechanism using solvent and a shop rag.
  • Follow the adjustment procedure outlined in your manual.
  • After adjusting the linkage, lubricate the mechanism, pivot points and sliding surfaces, using the lubricant recommended in your service manual.

Consult your service manual for the specific adjustment procedure, if necessary

3. Adjusting the Clutch Cable

  1. Locate the clutch cable housing adjusting nut, locknut (or wingnut), and adjuster nut at the cable bottom end where it attaches to the clutch operating lever.
  2. To increase clutch pedal free travel (lower clutch pedal), shorten the housing by turning the nut.
  3. To decrease clutch pedal free travel (raise clutch pedal), lengthen the housing by turning the nut.

See your vehicle repair manual, if necessary.

Some hydraulic systems allow adjustments that may help you fix clutch drag.

Some hydraulic systems allow adjustments that may help you fix clutch drag.

4. Adjusting a Hydraulic Clutch Mechanism

Most vehicles with a hydraulic clutch system are self-adjusting, but some can be manually adjusted. Consult your vehicle service manual, if necessary.

  1. Locate the adjusting nut on the fork push rod or cylinder master push rod.
  2. Loosen the locknut.
  3. To decrease clutch pedal free travel (raise clutch pedal), lengthen the rod by turning the adjusting nut.
  4. To increase clutch pedal free travel (lower clutch pedal), shorten the rod by turning the adjusting nut.
  5. Tighten the locknut.

The following video explains a hydraulic system clutch pedal adjustments and its effect on clutch performance.

On a hydraulic clutch system, check for leaks at these points as well:

  • clutch master cylinder (fluid should be about 1/4 inch [6.35mm] from the top of the reservoir)
  • hydraulic hose
  • slave cylinder

If your hydraulic clutch system is experiencing clutch slip, there could be a problem in the clutch assembly. You may need to replace the clutch disc. If the clutch drags, check the hydraulic system.

IV. Checking the Clutch Linkage

Although not as common, a clutch linkage can also develop problems over time.

  • Park your vehicle in a flat surface.
  • If necessary, raise the front of the vehicle and safely support it on jack stands.
  • Check along the clutch linkage for bent, binding or broken parts.

If clutch pedal free play is OK, and you can't find anything wrong with the clutch linkage, then you may need to drop the transmission to check the clutch assembly. Consult with a reputable car shop before doing any major transmission work.

V. Clutch Assembly Problems

Internally, the clutch assembly can also cause a clutch to drag. These problems are harder to diagnose without taking a look at the assembly itself.

Internal clutch assembly and related hardware problems may include:

  • Warped pressure plate
  • Warped clutch disc
  • Loose clutch disc lining
  • Faulty release fork or lever
  • Throw-out fork off pivot
  • Binding or seized pilot bushing or bearing
  • Binding or seized throw-out bearing
  • Clutch disc hub binding on transmission input shaft
  • Misadjusted clutch master cylinder
  • Hydraulic system in need of bleeding

Consult your vehicle repair manual to check and bleed the hydraulic system, and to check and adjust the master cylinder, if necessary.

Engine rear with clutch assembly exposed, transmission has been removed.

Engine rear with clutch assembly exposed, transmission has been removed.

VI. Should You Be Worried About Your Clutch Drag

Operating a transmission with clutch drag will turn into a very expensive repair if not corrected early. It can seriously damage your transmission. When necessary, have the problem diagnosed by a reputable shop.

Some manufacturers recommend checking (or adjusting) clutch pedal free play every 6,000 miles (10,000 km). Consult your vehicle repair manual.

Trouble signs of clutch drag are usually caused by too much free play in the clutch pedal.

Other times, you may need to take a look under the hood or raise your vehicle and inspect the clutch linkage mechanism. Sometimes a little lubrication job may solve your problem.

On rare occasions, you'll be dealing with linkage problems or internal clutch assembly issues.

If none of these issues seems to be the problem, and your vehicle has high mileage, you're probably dealing with a worn out clutch disc.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2019 Dan Ferrell

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