Reverse gear crunch - one for Ken?

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Oscar
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Reverse gear crunch - one for Ken?

Post by Oscar » Wed Jan 04, 2006 11:42 am

Hello

I read off another thread that it's possible to adjust reverse gear to make selection easier. My reverse has taken to crunching something horrible every so often when I select it. Can anyone (Ken) talk me through what I might need to do to make it better?

I've had a new clutch and gear selector arm and bush fitted, it was crunching before that, and doesn't seem any better or worse since.

Oscar
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DavidRutherford
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Post by DavidRutherford » Wed Jan 04, 2006 11:52 am

The reason reverse gear crunches rather than any other gear is because on a BE type gearbox, there is no synchromesh on it.

If reverse is crunching badly, then it may be that the clutch cable needs adjusting, as the bite point may be too low, and you're getting a little clutch spin (not fully dis-engaging) Does the clutch bite low and then have several inches of "nothing" at the top? I had a Cavalier like this a while ago... I thought it was just me being lazy, but with just 2 turns on the clutch adjuster, the difference was amazing.

It may also be that you just need to wait a tiny bit longer between depressing the clutch, and engaging reverse. Once you've pressed the clutch, the primary shaft in the gearbox has to slow from 800rpm to 0rpm before you try and engage reverse, or it will grind. On a cold gearbox, with thick gear oil, the shaft will stop in under half-a-second, but if the box is hot, and the oil is less viscous, it could take a second or two for the shaft to stop.
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Oscar
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Post by Oscar » Wed Jan 04, 2006 11:58 am

Hello David

yes I've taken to waiting, but haven't paid enough attention to be able to tell whether it's making a consistent difference. Thanks for adjustment tip - the clutch is much lower since being replaced. Another job for the list.

Oscar
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Post by jeremy » Wed Jan 04, 2006 12:35 pm

Those who replace clutches seem to think that they must never adjust the cable and so invariably leave the pedal far too close to the floor at the breaking point. Adjustment often makes a world of difference to the gearchange quality. Its worth doing as in fact the clutch isn't freeing completely and so when the car is stationary, in gear and the clutch is down your new clutch is wearing away! You will also find a correctly adjusted clutch is lighter as the linkage is operating at its most efficient range.

Another thing that can cause problems is an excessive idling speed.

jeremy

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mnde
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Post by mnde » Wed Jan 04, 2006 1:34 pm

Absolutely! Now Ken has adjusted the clutch a couple of turns, the biting point is in a normal place, not "close to the floor"; reverse is easy to engage without graunching, even from cold, and generally gearchange is easier. A new clutch cable was installed in the car under previous ownership, but it wasn't adjusted.

Mark.
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DavidRutherford
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Post by DavidRutherford » Wed Jan 04, 2006 3:13 pm

Mark... It has to be said that your clutch cable was absolutely silly though wasn't it?! You had to crush the pedal into the carpet... as we both found out:

I skronked reverse gear, and Mark then promptly stalled it twice... we both felt very silly indeed, walking off making comments like "I can drive... no really, I CAN!"
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Stewart (oily!)
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Post by Stewart (oily!) » Wed Jan 04, 2006 5:06 pm

My BX seems to crunch into reverse unless I wait a second or put it in a forward gear first, clutch adjustment is crucial though.
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