Clutch "No Release" Problems

Clutch “No Release” Problems

Poor clutch release makes it difficult to start and stop the vehicle or change gears.

“No release” is probably the most common of all clutch problems. The purpose of the clutch is to couple and decouple the engine and transmission. Poor clutch release makes it difficult to impossible to start and stop the vehicle or change gears.

Common Clutch release problems

Air in a hydraulic release ­system;

A flywheel that has been machined too thin; or

A flywheel where the step or cup dimension is out of ­specification.

Another condition may be that the disc damper can interfere with flywheel crank bolts, resulting in no release as well. Flywheel step and cup dimensions are critical to proper clutch operation. Too tall of a step or too shallow of a cup can create a “thick disc condition.” A thick disc condition will reduce or eliminate clearance between the disc, flywheel and clutch friction surfaces and cause release problems. Flywheel runout should also be inspected.

The conditions listed above account for the majority of “no release” problems, but other, less common conditions do contribute to no release, as well: Bent drive straps on the clutch, worn pilot bearings, a bent release fork, or a worn or binding release cable can all contribute to release problems. Any component in the release system that flexes, like a fork or firewall, can “absorb travel” and cause no release.

Causes of Clutch Release Problems 

External: 

  • Contaminated hydraulic fluid;
  • Incorrect release system adjustment;
  • Air in the hydraulic release system;
  • Defective or worn release system ­components;
  • Defective or worn pedal bushings or ­brackets; or
  • Flexing of the firewall or any release ­component attachment point.

Internal:

  • Misalignment of clutch components;
  • Corroded, damaged or improperly lubricated input shaft splines;
  • Worn pilot bearing/bushing;
  • Worn bearing retainer;
  • Bent or worn release fork or pivot ball;
  • Worn linkage components;
  • Stretched release cable;
  • Excessive or incorrect flywheel machining;
  • Bent clutch drive straps;
  • Bent or distorted disc;
  • Improper transmission lubricant; or
  • Improper bolting of the clutch.

Courtesy of Schaeffler Group USA

You May Also Like

ECM Damage

Engineers have devised two strategies that can be called the “immune system” for the electrical system.

With even the most basic vehicles having more than 10 modules connected to hundreds of circuits, there is always a possibility that wires can get crossed. Engineers want to prevent damage to wiring, circuit boards and sensors if something goes wrong that causes a short or open. To avoid damage and possible fires, engineers have devised two strategies that can be called the “immune system” for the electrical system.

Compressor Oil for R1234yf

Working on R-1234yf systems is not that different from the R-134a variety.

Fuel Pumps and Cranking

Diagnosing the problem comes down to understanding what causes a loss of fuel pressure.

Ignition Coil Output

To see inductance inside the primary windings, use an amp probe placed around the positive wire for the ignition coil.

Nissan Key Will Not Start

Nissan keys use radio frequencies (RF) similar to other everyday wireless devices.

Other Posts

Can You Diagnose a TPMS Radio Wave?

There are a couple of approaches and tools you can use to diagnose a TPMS radio wave.

radio tower
Programming Options

Let’s help keep the code secure and your sanity intact.

CAN Bus Communications

There are three types of bus configurations that you will come in contact with — loop, star and a hybrid of both.

There are three types of bus configurations that you will come in contact with — loop, star and a hybrid of both.
Key Programming

Three situations might require key programming capabilities at your shop.

Key Programming has evolved over the years.