Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Radar on 27 March 2010, 21:26:48
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As above and had the wishbones changed and full geometry set. The steering feels much more responsive and the previous judder i used to get through the steering wheel has gone :y. Tony said the toe and camber was well out and made the necessary adjustments. However the car still pulls slightly to the left. (The wishbones were torqued up whilst on the ramp and Tony assured me there was no need to torque them up on the ground) .Is there something i have missed or can anyone give any pointers as to the cause?
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If it was on its wheels on the ramps, that's the same as being on the ground, no?
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The wheels were definitely off at the time and it was lifted from the jacking points (i think)
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The wheels were definitely off at the time and it was lifted from the jacking points (i think)
Well he's f*cked up then.... sorry, just has!
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The reason for having the car loaded is;
The bush has a centre spacer set int the rubber with the metal outer. When the bolt is done up on the wishbones and hence the bush centre spacer the centre spacer is clamped by the subframe bracket due to the force applied by the bolt.
If the wheels are hanging then the centre spacer is clamped with the suspension topped out/fully extended, with the centre spacer clamped in that position, which means the when the car is driven "on the ground" the wishbone rises from the clamped position, this means that the bush is constantly twisted. The more the suspension compresses, like when its dropped off the jacks, the more it twists the rubber in the bush and it rips the rubber apart causing early failure.
If tightened wheels loaded then the bush centre spacer is set in the middle of its travel in a neutral unstressed position. Only when the suspension moves up or down of the ride hight position does the bush become stressed. As opposed to over stressed all the time if tightened wheels hanging.
In effect the bush is trying to hold the car up in the air as its set now, because the bush naturaly wants to return to its unstressed position, that being with the suspension fully extended (wheels hanging)
asap i would get under the car and undo the bolts, esp the front horizontal bolts, the rear vertical bolts dont matter due the plane the rear bush operates in.(a thought occurs at this point, explane later)
You'll probably hear the centre spacer ping round when the bolt is released. Then do the bolts up to 120nm plus angle tighten 30° then 15° wheels loaded. This is a pig to do without a ramp as wim have as the floor is in the way of the torque wrench.
hth
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When mine were done down there, a hydraulic ram was used to load the suspension arm at tightening. Queried the matter but was told (nicely...) that it will be fine.
I am, however, starting to have some small doubts as to the handling, almost a year later. Might just be less than great wishbones though..... :-[
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When mine were done down there, a hydraulic ram was used to load the suspension arm at tightening. Queried the matter but was told (nicely...) that it will be fine.
I am, however, starting to have some small doubts as to the handling, almost a year later. Might just be less than great wishbones though..... :-[
Might be worth a bush examination and loosen and re tighten of the bolts...? what make where fitted do you know?
But the fact they used a ram is better than nothing, and brings me to my earlier thought.
The rear bush is set reguardless of wishbone angle. If its to be unstressed at the ride hight position then that assumes that the desired ride hight position is equal to the position of the rear bush.
In other words would it be safe to fit the wishbone, insert the bolts with nothing else fitted to the wishbone and tighten the bolts at this point of the fitting process. The rear bush would then set the ride hight of the wishbone(assuming that position is correct?) reason i ask is tightening the wishbone bolts at this point would be a dam site easier. Then once bolts are tightened attach the strut/hub which would then force the wishbone down.
This assumes too much re suspension components condition and that the car will settle at the tightened wishbone angle/ride hight...but it would be a alot easier to tighten the bolts.
Hope that makes some sence?
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The tightening of the bolts with the weight of the car on its wheels is purely to eliminate the risk of premature failure of the rubber bushes. Don't think it would affect the steering.
Sounds like WIM may need to adjust the camber a little more than their usual Mig settings.
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In reply to that query which was so eloquently explained by chrisgixer i too after having front camber set at -1.10
by myself it still pulled to the left sllightly
so my settings are now Left Side -1.18 Right Side -1.10
the steering wheel is straight and the car drives as straight as an arrow i achieved these settings as i have previously said by measuring rim top and bottom and having a difference from top and bottom of 9 mm on Left side and 8mm on Drivers side maybe you might not aggree with this way but both my 2.5 CDX and my latest 3.2 elite ran with these Settings .after i had done this i went to the Local tyre fitters and asked them to check my settings that i suspected i had a Fault and would be changing something Steering Idler etc so they obliged and never charged as they did not change anything and the result was i got a read out for nothing
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Be aware that even with bang on geometry you can have tyres which have a bias fault causing pulling to one side or the other..........
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Be aware that even with bang on geometry you can have tyres which have a bias fault causing pulling to one side or the other..........
very much so, and is exactly why i'm being so cautious before putting my 245 40 18s on, this is hard enough(and expensive enough) without without cock ups mentioned above.
I suppose we should give wim the benefit of the doubt though. There may well be something wim did that Radar didnt see that corrects matters. But on the evidence so far its just not correct procedure...
...also suprised others havent commented, maybe its just me?
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Be aware that even with bang on geometry you can have tyres which have a bias fault causing pulling to one side or the other..........
very much so, and is exactly why i'm being so cautious before putting my 245 40 18s on, this is hard enough(and expensive enough) without without cock ups mentioned above.
I suppose we should give wim the benefit of the doubt though. There may well be something wim did that Radar didnt see that corrects matters. But on the evidence so far its just not correct procedure...
...also suprised others havent commented, maybe its just me?
Thanks for replies :y It was just the front wishbones replaced (lemforder). Tony did explain to me that the torquing up was the same as if it were done on the ground but i'm afraid he lost me in his explanation.
I did get the front passenger tyre changed the night before and despite me telling them what psi to inflate to i checked yesterday and it was 2psi lower than all the other tyres. I think the tyre bias point is a point to be noted and all in all it is much better than before with handling feeling more solid.
I wish i had more technical know how to explain why wim said it was ok but i don't.
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We put a hydraulic ram under the wishbone and jack it up until it's horizontal so there's no preload in the bushings.
The camber positions are very safe and will not cause a pull, this is probably the tyres.
In addition we can adjust the castor angle if needed to stop a pull but in this case it wasn't necessary.
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We put a hydraulic ram under the wishbone and jack it up until it's horizontal so there's no preload in the bushings.
The camber positions are very safe and will not cause a pull, this is probably the tyres.
In addition we can adjust the castor angle if needed to stop a pull but in this case it wasn't necessary.
Thanks for clearing that up Tony, I guess the jack goes under the ball joint point (beware, jacking under the wishbone bends them! )
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
ok, but its already on a ramp surely? why introduce another process? just wack the wheels on drop it on the slide plates they have on that hawk eye ramp and do the bolts up? :-/
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
ok, but its already on a ramp surely? why introduce another process? just wack the wheels on drop it on the slide plates they have on that hawk eye ramp and do the bolts up? :-/
Indeed but, I guess it depends if they are doing the work on that ramp or not....as I guess that would be utilised for alignment work so you can sweat the expensive asset in the form of the alignment kit
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
With a digital level?..... Rule of thumb is the wishbones are horizontal so that the roll centers comply with the original build, we use a ram because we can, just because members haven't heard of this before doesn't make it wrong!
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
ok, but its already on a ramp surely? why introduce another process? just wack the wheels on drop it on the slide plates they have on that hawk eye ramp and do the bolts up? :-/
Indeed but, I guess it depends if they are doing the work on that ramp or not....as I guess that would be utilised for alignment work so you can sweat the expensive asset in the form of the alignment kit
had that thought, the other two ramps are chassis lifts not drive on jobs (whatever they're called) iirc
anyway, i'm sure they have thier reasons...
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
With a digital level?..... Rule of thumb is the wishbones are horizontal so that the roll centers comply with the original build, we use a ram because we can, just because members haven't heard of this before doesn't make it wrong!
forgive me, roll centers?
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We put a hydraulic ram under the wishbone and jack it up until it's horizontal so there's no preload in the bushings.
The camber positions are very safe and will not cause a pull, this is probably the tyres.
In addition we can adjust the castor angle if needed to stop a pull but in this case it wasn't necessary.
Thanks Tony for clarification.
I also wish to add for anyone reading that i was very happy with the service you provided and my query only came about due to my lack of knowledge on the subject (which through this discussion has increased for me and hopefully others too) :y
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
ok, but its already on a ramp surely? why introduce another process? just wack the wheels on drop it on the slide plates they have on that hawk eye ramp and do the bolts up? :-/
I suppose because the wheels are already off it would waste time putting them back on
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ok good news, so to my earlier "thought" then...
does it amount to the same thing if....
the new wishbone is placed in position bolts inserted loose, the strut is pulled clear and the wishbone allowed to find its own position as dictated by the rear bush, being vertical/fitted flat it will presumably ammount to the same end result, that being a level wishbone. Then simply do the bolts up as is...? same fing no?
Must say i think i would prefer the car off the jack then the bolts tightened at the true ride hight, but doing so on a drive way is such an almighty pita, would this method surfice?
seems easier to me?
Not keen on that idea as the wishbone does not sit at 90 degress to the rear bush and differs dependent on engine fitted (and hence weight at the front) and suspension setup
agreed, so how is done to the appropriate level of accuracy with a ram?
With a digital level?..... Rule of thumb is the wishbones are horizontal so that the roll centers comply with the original build, we use a ram because we can, just because members haven't heard of this before doesn't make it wrong!
forgive me, roll centers?
Taken from the wim forum (without pictures)... enjoy.
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The roll centre is an imaginary point about which the vehicle rolls. The calculation process that’s followed to find the roll centre varies a little according to the suspension design; this diagram shows the approach for double wishbones where one wishbone is angled to the horizontal. The lines of the wishbones are extended until they reach a common point – ‘A’. A line is then drawn that connects ‘A’ to the centre of the tyre’s contact patch – ‘C’. The roll centre is where this line crosses the centreline of the car – ‘R’.
The amount of body roll that occurs with a given cornering force largely depends on the relationship between the height of the centre of gravity and the roll centre. Raising the suspension roll centre, or lowering the centre of gravity, will decrease roll.
However, while having a high roll centre therefore sounds attractive, it has significant negatives associated with it. In fact, most well set up vehicles run a roll centre at, slightly above, or slightly below ground level.
So what does this mean to you?
Effectively, the only thing you are interested in is the centre of gravity of the sprung mass. Imagine attaching a string to this point and pulling - sideways to simulate a cornering load, fore or aft to simulate acceleration or braking, diagonally to simulate a combination. The attitude a car adopts when subject to these forces is dependent upon how stiff the springs and anti roll bars are, and of course these will be different front and rear. Due to differing roll resistances front and rear, and the fact that weight is transferred diagonally, the car will almost always be operating in what Allan Staniforth refers to as 'skewed roll' - ie. a combination of roll and dive/squat.
The main implication of the roll centre locations are that they are used to calculate diagonal weight transfer, which in turn can be used to derive suspension deflection and individual tyre loads (which in turn influence understeer/oversteer balance).
The traditional rule of thumb was that that the roll centre is lower at lighter end of the car, but many other factors have to be taken into account - spring/roll bar stiffness, tyre sizes, front and rear track, CG location etc., so this rule is by no means hard-and-fast.
Probably more important to make sure that your roll centres don't move about much in relation to the sprung mass, as movement changes the diagonal weight transfer and can lead to very uncertain handling characteristics.
Steady state under constant lateral acceleration:
The total amount of lateral weight transfer is determined by the CoG position and track width.
Some of the lateral weight transfer occurs through the suspension links. This is what I term unsprung weight transfer. The amount for each axle can be determined from the weight on the axle and the position of the roll center for that axle. Obviously the answer can and usually will be different for each axle. It's independent of spring rates etc.
The remaining lateral weight transfer i.e. total minus unsprung is what I call the sprung weight transfer. This occurs because the body rolls and deflects the springs, dampers and anti-roll bars etc. The body is usually stiff enough that the front and rear roll can be considered identical. In a steady state the sprung lateral weight transfer is divided between the front and rear axles in proportion to the roll stiffness i.e. front twice as stiff in roll as the rear means the front sprung lateral weight transfer will be twice as much as the rear. There's a slight subtlety - it is actually the roll moment which is divided in this ratio. If the front and rear tracks are different then the weight transfer will be proportional to roll stiffness divided by track, not just proportional to roll stiffness. But to avoid getting a headache let's pretend the front and rear tracks are always the same, in that case the weight transfer is proportional to roll stiffness.
If you change the springs and/or anti roll bar stiffness to change the ratio of front versus rear roll stiffness then this will have effect of increasing the sprung lateral weight transfer at the end you are making (relatively) harder, and reducing it at the end you are making (relatively) softer. The total is fixed, so if you take 50 lbs of weight transfer away from one end, you will end up adding 50 lb
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If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y[/quote]
I think this is the best explanation as to why it is ok to torque up by the wim method (especially for a techno retard like me!) :y
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If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
I think this is the best explanation as to why it is ok to torque up by the wim method (especially for a techno retard like me!) :y [/quote]
In addition when this is done the damper is not connected to the hub.
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If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
I think this is the best explanation as to why it is ok to torque up by the wim method (especially for a techno retard like me!) :y
In addition when this is done the damper is not connected to the hub.[/quote]
i think what we're interested in is weather the the wish bone bush is clamped in the subframe at the same position as when assembled and on the road.
i cant see how thats achieved with the shock removed from the hub ?
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If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
I think this is the best explanation as to why it is ok to torque up by the wim method (especially for a techno retard like me!) :y
In addition when this is done the damper is not connected to the hub.
i think what we're interested in is weather the the wish bone bush is clamped in the subframe at the same position as when assembled and on the road.
i cant see how thats achieved with the shock removed from the hub ?[/quote]
I will draw some pics and do some WIM reading tomorrow so I can get the theory straight in my mind.
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Under normal load the wishbone sits horizontal. As long as the bolts are tightened in that position i carnt see what difference it makes if the strut is attached or not.?
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If you apply a jack or lift under the ball joints so the vehicle weight at the front is resting on this then the suspension will be compressed by the cars weight in the same way as if the wheels were fitted and sat on the ramp. :y
I think this is the best explanation as to why it is ok to torque up by the wim method (especially for a techno retard like me!) :y
In addition when this is done the damper is not connected to the hub.
i think what we're interested in is weather the the wish bone bush is clamped in the subframe at the same position as when assembled and on the road.
i cant see how thats achieved with the shock removed from the hub ?
I will draw some pics and do some WIM reading tomorrow so I can get the theory straight in my mind.[/quote]
indeed, i've read the roll centre piece a couple of times and dont yet see the link between matching the ride hight of the wishbone to the clamped position of the bush.
...i.probably need the pictures. ::) ;D
and whats up with these quotes?
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Under normal load the wishbone sits horizontal. As long as the bolts are tightened in that position i carnt see what difference it makes if the strut is attached or not.?
Thats the thing, it doesn't, it differs from model to model dependent on engine fitted and suspension setup.
Mv6 is close to level....others are angled downwards (as you would expect with a ride 30mm higher)
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Under normal load the wishbone sits horizontal. As long as the bolts are tightened in that position i carnt see what difference it makes if the strut is attached or not.?
does it sit level though? exactly level? bit splitting hairs to be fair, but say the cars been lowered(i know wim always ask that but as an e.g.) or has brand new shocks and springs or old tired worn out suspension. Will the chassis, and hence the wishbone angle, ride at the same hight in all three senarios? I dont think so.
It will be far closer than wheels hanging of course. But we want zero stress in the bush or as close as possible. They'll last longer.
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Under normal load the wishbone sits horizontal. As long as the bolts are tightened in that position i carnt see what difference it makes if the strut is attached or not.?
Thats the thing, it doesn't, it differs from model to model dependent on engine fitted and suspension setup.
Mv6 is close to level....others are angled downwards (as you would expect with a ride 30mm higher)
I agree with you on that one .Before strip down its would be a good idea to note angle of wishbone on the car being worked on and then set it to the same when bolts are tightened. But i still dont think its a problem cranking bolts up with strut not attatched. personally i would do it with wheels on car on the ground but thats a no go due to ground clearance. Bets on a ramp if you can. When i done mine i used trolley jack under strut and lifted it up to the load angle then tightened bolts.
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Under normal load the wishbone sits horizontal. As long as the bolts are tightened in that position i carnt see what difference it makes if the strut is attached or not.?
Thats the thing, it doesn't, it differs from model to model dependent on engine fitted and suspension setup.
Mv6 is close to level....others are angled downwards (as you would expect with a ride 30mm higher)
I agree with you on that one .Before strip down its would be a good idea to note angle of wishbone on the car being worked on and then set it to the same when bolts are tightened. But i still dont think its a problem cranking bolts up with strut not attatched. personally i would do it with wheels on car on the ground but thats a no go due to ground clearance. Bets on a ramp if you can. When i done mine i used trolley jack under strut and lifted it up to the load angle then tightened bolts.
or, put it another way, when i fit new mv6 lowered sport chassis shocks and springs next week i'll need to undo the wishbone bolts to let the bush sit unstressed at the new wishbone angle, because those components let the chassis sit 15 mill lower.