Car Suspension -adjustment

  1. fran9r Member

    Messages:
    73
    Grantham
    I'm wanting to put an A3/Golf 4x4 rear axle on a MK3 Caddy van.

    The stock Caddy uses leaf springs. I want to convert to the above rear suspension, which has been done with some fabbing to mount the rear subframe.

    What I need help with, is what adjustment to add to the suspension while I'm playing, and how. For example, I need to weld in rear turrets -so how do I select the correct length and geometry for that?

    I know I could use the donor car shocks, but the van will weigh more and not really supposed to support my motorbike in the back either.
     
  2. johnser

    johnser Member

    Messages:
    1,753
    Location:
    North Cornwall
  3. garethp Forum Supporter

    Messages:
    829
    sw scotland
    If you have the donor car for the rear axle you could make a frame which picks up all the mounting points and then move that to under the van to give you a very accurate base to work from, with a bit of thought you can line it up using measurements from the front suspension mounts.

    I cant claim any credit for that idea - search for 'project binky' on YouTube if you haven't already seen it, the early episodes show what I mean.

    You don't need to go as complex as they went with the full motion jig they made.
     
    fran9r and Pigeon_Droppings2 like this.
  4. stuvy

    stuvy Member

  5. armalites Member

    Messages:
    3,943
    Herefordshire
    As @garethp said what they did in simple terms on Project Binky was make a subframe mould. It meant when they had finished fabricating the subframe fit the new vehicle in exactly the same way it did on the donor vehicle.
     
  6. rcx132

    rcx132 Philip

    Messages:
    1,842
    Location:
    London, UK
    Suspension geometry needs to be designed if you want good handling. I remember a guy on another forum couldn't even get his car up a ramp, his home made suspension geometry had so much anti-dive at the front that as soon as his wheels hit an obstacle the suspension would lift the car. The good news is that its not that difficult and can be done by eye. Or could you copy the geometry from the donor car?
     
  7. fran9r Member

    Messages:
    73
    Grantham
    I can copy the donor car geometry, but not sure if that could be improved upon.

    Anyone made camber and castor adjustable top mounts?
     
  8. rcx132

    rcx132 Philip

    Messages:
    1,842
    Location:
    London, UK
    I've just started my custom suspension. I've done it by eye and using sketches so far but will make it more accurate later. What suspension setup is on your car? If it's Mcpherson then should be easy to make camber and castor adjustable.
     
  9. Ruffian Member

    Messages:
    1,630
    Location:
    Devon UK
    If your using a mk4 golf axle they are quite silly same as the tt and lots are becoming rotten.
    The a3/mk5 setup is nicer.

    But if you were to do it I would be looking at building your own setup similar to caterham or kit car suspension then splicing that in.

    If your trying to do it so you can still fit your motorcycle in then probably better cutting in turrets for coil overs.
    Top mounts aren't difficult, people use rally design or Peter Lloyd rallying for mk1 escort ones that are fairly universal.
     
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