It's not so much redudnant as reinforcement; it all depends on the orientation with which all this is installed: you might be lifting the clamp with respect to the terminal post (i.e. along its axis), but you might need to do this in an upward direction (geographically!)

It may be you don't need to use two separate terms in FR, but in EN, it reads better and reinforces the notion of the movement required. One might argue simply that the verb 'lift' was not best chosen...

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Note added at 1 hr (2012-12-11 15:40:47 GMT)
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That's why I said, it is possibly 'lift' in the sense of 'along the axis of the terminal' (which might well be horizontally mounted), but doing so in a physically upwards direction.

The writer may be making a specific distinction here, or it may just be the common EN usage 'to lift something up', but used with 'upwards' to suggest direction only (rather than the idea of 'raise a load' etc.)

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Note added at 1 hr (2012-12-11 16:08:18 GMT)
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I'm not so sure, Gilles: 'wiggle' is one thing (suggesting a rather random freeing or loosening action), whereas 'lift' suggests a more purposeful movement in a specific direction.