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Old 08-14-2007, 09:58 AM
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Muncie M21 rebuild.

Hi , I have a 68 firebird with a 400 and an m21 trans. The clutch is bad or needs adjustment and the trans might need rebuilding. I bought it on ebay and have not been able to drive it yet because of the clutch.In gear with the clutch released the car moves about an inch .The guy I bought it from told me the clutch was bad but he also thought the motor was a 350 ,I dont trust anything he says, so I would like to try some adjustments if possible before pulling it apart.I really dont have any knowledge of manual trans and clutches but want to learn.
Any input would be appreiciated Thankyou. John

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Old 08-14-2007, 12:28 PM
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First check the free travel of the clutch petal. Make sure the clutch linkage is not holding the throw-out bearing on the pressure plate fingers when the petal is released.

You should have 1-2" of petal free travel before the throw-out bearing even touches the pressure plate fingers.

Is the shifter actually putting the trans in gear?
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Old 08-15-2007, 05:49 AM
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It has a weird type of shifter. I think it is called a short throw shifter (hurst)It only seems to move about 1 quarter inch between gears, Does that make sence?
yes , I believe it is going in gear because in neutral it does not do anything.
The clutch pedal has lots of pressure it is NOT slopply or loose.Where do I look to see the throwout bearing and pressure plate fingers? Like I said I am an idiot on trans and clutchs but learn quick. Thanks
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Old 08-15-2007, 09:29 AM
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1/4 inch between gears? That seems VERY short. Back off the stops for the time being and see what happens. Is the shifter installed correctly? Has someone left the neutral gate pin in?

Probably won't be able to see the clutch and Throw Out bearing if you have a full bell housing. This is something you will have to do by feel and by watching the TO bearing arm.

You might be able to see what's going on inside the bell housing by removing the rubber boot around the TO bearing arm. You will also see that the TO bearing arm has a pivot inside the bell housing.

The idea is to have the TO bearing, when the clutch petal is not depressed, NOT touching the pressure plate release fingers. There should also be a spring pulling the clutch arm/TO bearing away from the pressure plate release fingers. This spring will be pulling the TO bearing arm towards the front of the vehicle.

The best way to get a feel for the free travel is to release the spring so you can move the TO bearing arm easily. Push the arm towards the rear of the vehicle. If the linkage has slack in it when you do this there is probably enough free travel. If you can't move the arm at all or very little, then you need to adjust free travel. Adjustment is made with the the linkage.

This is way harder to explain than to do.

Quote:
Originally Posted by 1genbird
It has a weird type of shifter. I think it is called a short throw shifter (hurst)It only seems to move about 1 quarter inch between gears, Does that make sence?
yes , I believe it is going in gear because in neutral it does not do anything.
The clutch pedal has lots of pressure it is NOT slopply or loose.Where do I look to see the throwout bearing and pressure plate fingers? Like I said I am an idiot on trans and clutchs but learn quick. Thanks
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Old 08-17-2007, 08:30 PM
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yeah i think your gates on your shifter are tightened to much im preaty sure the shortest throw hurst makes is 4 1/8inch end travel between gear to gear
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Old 08-19-2007, 06:33 PM
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I need to find a stock hurst shifter ,It is a compitition plus that is off set.Someone cut out the tunnel to make this one fit and it looks like crap. If anyone has one for sale that is complete with linkage please let me know. Thanks.
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