AR7E - Alcester Racing 7's Equipe
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Ok, we're pulling pretty much all of the mechanical items at the back end of the car apart in order to remove the diff and gain access to the propshaft for replacement... Step five will see us disconnect most of the suspension - ready to drop the diff.
Basically, all we are going to do is remove the A-frame (see picture above) and disconnect the De Dion tube from the spring/damper units. We don't need to remove the trailing arms or even the De Dion tube itself - this can be slid comfortably out of the way instead. One suggestion, before we move on, is to cover the chassis tubes that run underneath the De Dion tube with plenty of insulation tape (or similar). The De Dion tube will be resting temporarily on these tubes and may need to slide back and forth when the diff is removed. The order in which we do this is not terribly important - you can tackle either the A-frame or the dampers/springs first. Let's go for the spring/damper units first... These are connected to the De Dion tube by a single bolt on each side. Don't be frightened - the spring won't suddenly go sproing when you undo the bolt - it is already at maximum extension anyway (assuming that the suspension was allowed to hang down from the chassis without support from axle stands and/or a jack....) You will need to ease the De Dion tube down onto the chassis rails though...
Click Image for Full Size Key: A - Rear A-frame pivot B - Front-righ A-frame pivot (also secures Rear Wheel Intrusion Bar) C - Driveshaft/disc/hub unit removed in earlier phase OK, now the dampers are disconnected, it's time to remove the A-frame itself. Start with the rear, centralised pivot - this has a single bolt running straight through from one side to the other. Take care of any washers etc. - and note that you might need to use a deep socket on the nut end of the assembly - the bolt can protrude through the nut to such an extent that a conventional short socket won't engage the nut properly... With the rear pivot undone, the A-frame should droop down as in the picture above. You might be surprised that the A-frame does not freely pivot - there is quite a lot of resistance... Why? Well, the pivots are actually based around metalistic bushes. Broadly speaking, these consist of a chunky cylinder of dense rubber material that fits inside the pivot tubes of the A-frame (in this case... they are used throughout the suspension). When the bolts are tightened up, the suspension movement actually takes place by deforming the rubber core in a twisting motion - this helps reduce any sharp jolts being transmitted to the chassis and also has the side-effect that the suspension pivots don't actually need lubrication - there are no 'moving' parts as such... Anyway, the important point of this digression is that when the suspension is reassembled, the bolts binding the metalistic bushes should not be fully torqued up until the weight of the car is taken up by the suspension - i.e. so that the bushes are not being twisted until the car hits a bump... Oh - there is another point to bear in mind - now that you know how a metalistic bush works, you'll appreciate that in order to force any movement to take place through the twisting deformation of the rubber (rather than through the whole unit pivoting on the bolt), the bushes need to be clamped very hard indeed - so don't be surprised at how difficult it is to remove the bolts in the first place... OK, if you haven't done so already, undo the two pivots at the front of the A-frame (again noting that you may need a deep socket to grasp the nut end of the assemblies due to the protruding bolt). You can now take the A-frame (and rear anti-roll bar) out from under the car - and possibly inspect it for rusty chips to the powder coat while you are at it... The De Dion tube can also be carefully slid to the back of the chassis rails - or removed entirely (remembering to remove the brake pipes) if you so wish... And now we're almost there... 'just' the diff and propshaft to go... |
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