Catching Clutch Slipping Problems - Four Areas That Could Be The Culprit -

Catching Clutch Slipping Problems – Four Areas That Could Be The Culprit

Clutch-Friction-Mat-2Once a clutch starts to slip while engaged, its lifespan will be very short. Slipping­ ­increases wear; slipping also generates heat that increases the wear on the disc and causes the friction material to glaze and crack. It all happens very quickly. The real tragedy is when it happens to a newly installed clutch. Here are four problem areas that can cause a fresh clutch to slip.

  1. Material is Worn: Friction material is usually riveted to the disc. If the material is worn to the rivets, the clutch will slip. Also, the loss in thickness will prevent the pressure plate from putting the full clamping force on the disc.
  1. Contamination: If engine oil, gear lube or brake fluid from the slave cylinder makes it past the seals onto the disc, it can cause the disc to slip. ­Replacing the seal is important, but diagnosing why the seal failed is even more critical. Often, a plugged crankcase or gearbox breather will cause higher-than-normal pressures inside the case and push oil past the seal. Worn pilot and input shaft bearings can also cause the seals to leak.
  1. Problems with Alignment: It’s extremely important that the flywheel, clutch disc and clutch pressure plate operate in an exactly perpendicular plane with the engine crankshaft and transmission input shaft. If the bellhousing surfaces of the engine or transmission aren’t cleaned before reassembly, or the bellhousing is warped, the flywheel and clutch assembly will not be operating perpendicular to the plane of engine and transmission rotation. When excessive flywheel, disc or pressure plate runout occurs, the air gap diminishes until the disc begins dragging against the flywheel. When this ­occurs, the manual transmission grinds going into reverse, and forward gear engagement becomes ­increasingly difficult.
  1. Pressure Plate Problems: The pressure plate must apply a tremendous amount of pressure against the clutch disc to keep the clutch from slipping against the flywheel at maximum power output. Generally speaking, the minimum clutch pedal travel in most vehicles is about 4”. To achieve complete release, a typical pressure plate must create an air gap of about 0.050” ­between the disc and flywheel. This amount of air gap is required to compensate for disc marcels and minor amounts of runout that occur in the flywheel, disc and pressure plate during manufacturing. Obviously, disc thickness of 0.020” leaves only about 0.030” of clearance or “air gap” to disengage the disc from the flywheel.




You May Also Like

How ADAS Systems Perform

When new technologies are applied to driver safety, a higher level of scrutiny and service is required.

New automotive technologies might work great when they roll off the dealer’s lots, but independent shops know that some technologies do not age well. It could be an LCD digital dash now blank or a variable valve timing actuator damaged internally due to a lack of oil changes. However, when new technologies are applied to driver safety, a higher level of scrutiny and service is required.

Air Ride Suspension Diagnostics

The key to understanding the embedded logic of air ride systems is using service information.

Steering Angle Sensor 101

The steering angle is used by many ADAS functions.

BMW N54 Turbo Problems

Here are some common problems or failures that you should be on the lookout for.

Mercedes-Benz Engine Oil Leaks

Mercedes makes a fine product, but certain repairs will emerge as trends over time.

Other Posts
Brake Pad Wear Sensors

Brake pad wear sensors have been around for years and continue to evolve.

Turbocharger Topics

Turbochargers have made a comeback – and it’s been quick.

Clutch Release Problems

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

Clutch Release
Drilled and Slotted Rotors

There’s real science behind the location of holes, slots and grooves in today’s brake rotors. Plus, they look great too.