Clutch problems!

This topic contains 3 replies and was last updated by derek-hawes 8 years 7 months ago
September 13th, 2012 1:00pm
I'm working on a freightliner with a mercedes engine, eaton-fuller 10 speed manuel. The clutch is making a grinding sound. The clutch springs are completely compressed, and never release. My guess is a throw-out bering being my problem? What is the purpose of the clutch springs? What is the proper movement of the clutch and springs?
September 13th, 2012 8:02pm
There are several places where the noise could be coming from.

1. The centre bearing - locates the input shaft to the centre of the flywheel. When the engine is turning and the input shaft is not the bearing will be functioning. If the bearing has failed you will hear noises and vibrations.

2. Input shaft bearing - located in the front of the transmission. Will make noises when the shaft in turning and especially when torque is being applied.

3. The release bearing - located of the input shaft to disconnect torque from the engine. Put pressure on the clutch pedal the bearing starts to turn and run up. The bearing is turning when the speed of the input shaft and the flywheel are different for shifting purposes.

4. The clutch disc and/or pressure plate - If the clutch disc has come apart, pieces could be causing noise. pieces usually fall down into the clutch cover.

If the clutch disc has been warped because of overheating, will want to keep the input shaft turning and make shifting more difficult.

If a pressure plate spring has broken, particles will usually show up in the clutch cover but other pieces may be trapped creating a rubbing noise.

You need to diagnose by knowing when you hear the noise and under what conditions.

Clutch adjustment - 1/8" and 1/2" clearances.

1/8" means at the fingers of the clutch release yoke to the bearing itself. Use something like a drill bit or a welding rod to check the clearance. This is adjusted by turning the internal ring inside the pressure plate.

1/2" means the clearance between the release bearing and the clutch brake which is next to the transmission housing.


If the clutch is properly set up, you should be left with 3/4" to 1 1/4" pedal free play at the top when fully released. Ensure that the pedal is coming completely to the top and is against the rubber stop.

When the pedal is fully depressed, you should feel the release bearing compressing the the clutch brake about 1" from the floor.


If the settings you have do not work out, check for bent linkage, worn clevises and pivot points, and broken linkage springs.

There is LOT more to know about clutches but you need to absorb this stuff first. Hope it helps.
September 13th, 2012 9:33pm
Re-reading my post, I realized that my description may have been overly simplified. I apologize.

Anything that you have trouble understanding, let me know and I will clarify.
September 14th, 2012 10:58pm
Thanks for your help Jim.

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