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post #7 of (permalink) Old 30-03-2005, 08:29
Scarlet Fever
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Join Date: Jul 2002
Location: Near Stansted Airport
Car: MGF
Posts: 5,476
Blog Entries: 9
I'm with Seffainn on this one.

Normal Abingdon = 368mm + / - 10mm @17 degrees, measured vertically from the centre of the front wheels only to the underside fo the wheelarch.

Lowered Abingdon with knuckles = 340mm (same conditions as above).

The suspension can be lowered to this level without knuckles, in this case the system is underpressure and risks long term internal damage (plus a very poor ride).

Because the lowering knuckles are simply standard items with shorter pins, and because the pins are inserted into the underside of the lower Hydragas sphere, there is no way to tell by inspection without dismantling the suspension. The only way to tell is to connect a Hydragas pump to the system and check the pressure. Lowering knuckles are a mechanical means of lowering, therefore with or without them fitted the pressure should be the same.

Average 'normal' Hydragas pressure = circa 400psi

If the car is low, with around 400psi in the system then it has lowering knuckles (it has been lowered properly). If it is lower than 400psi (say 375 or below) then it has been lowered through depressurisation (and if it has been driven like this for a while it may have sustained internal damage to the system due to extra travel in the components).


Low + 400psi = Good news - lowered properly with knuckles
Low + < say 375psi = Bad news, no way to tell if this has been done to make the car look more sporty by the seller (short term, ergo no real problems), or was done ages ago by the owner and may have caused damage, or even if the car has a leaking system (are both side the same height? F has a left system and a right system, if the car is even it is likely to have been deliberately lowered, if it is uneven, then there is likely to be a leak).
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