Hornet
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| posted on 6/5/03 at 08:56 AM |
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Suspension movement
So..... a daft question to ease my mind. 
I have manufactured all my suspension components, arms bushes etc. and my question is....
Without the shocks fitted, how "slack" should the movement of the arms be? Easily by hand or some resistance?
Probably doesn't matter once weight of car is on them . But would like to know from others experiences.
Cheers 
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stephen_gusterson
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| posted on 6/5/03 at 09:41 AM |
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depends on what slack you have - a lot or none!
if its a lot, then the MOT / SVA wont want to feel any movement at all side to side, but obviosly some up and down with the suspension movement, but
not without corresponding movement of the shocks.
Im guessing that you mean the suspension is stiff - and that you have rubber suspension bushes....?
If so, search Rortys posts - you will find some on suspension bushes. The rubber types should be clamped by the bolt, and held firmly in the
'bones. This means that any movement must 'twist' the rubber, which is the way they are supposed to work. Dont tighten up the bolts
until the car is at normal road height.
atb
steve
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Hornet
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| posted on 6/5/03 at 10:03 AM |
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Hi Steve.. No my bushes are PU and a crush tube. Bush dimension overal is 40.6mm and crush tube 41mm Brackets are 41mm so with all tightened up..
only movement is bush around crush tube. tube od is 15.99mm and bush bore is 16mm.
TBH both are 16mm so i think this is where the "stiffness " is coming from.
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Alan B
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| posted on 6/5/03 at 01:32 PM |
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Hornet, it depends how stiff really.
If you were to lift up the hub and let go does it fall by itself or need assistance?
If it fell very freely I'd say it was a bit loose for poly (but perfect for rose joints for example), ITOH if it needed decent force to push it
down I'd say it was too stiff.
So for poly I think I'd look for somewhere between just falling under it's own weight to a light downward push needed.
Does that make sense?
Alan B
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Alan B
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| posted on 6/5/03 at 01:35 PM |
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To follow up:
If you determine it is too stiff, then I'd isolate each wishbone in turn to find the stiff one, then investigate why.
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dozracing
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| posted on 7/5/03 at 01:17 PM |
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The problem i have found on my car is that the crap wishbones i got from Stuart Taylor (most suppliers have the same problems mind) have the tubes
where the bushes pissed relative to one another.
So when you bolt them to the car and move the suspension it wants to pivot about two different axis' and therefore goes stiff. Its only the fact
that there is any sort of compliance in the PU that allows any sort of movement.
I'm trying to make a set of wishbones now using a different manufacturing method to correct this problem.
Kind regards,
Darren
www.gtstuning.co.uk
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Hornet
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| posted on 7/5/03 at 03:01 PM |
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Darren
I have made a jig that lines up the bush holders perfectly. I have machined solid round bar that is held in place inside the bush holders. I then
tacked all together in position.
On completion of welding, you just dismantle jig and hey presto...
The only problem is you still get a little heat distortion. But i know the bushes are on the same axis.
I can send you a photo if u wish.
PS update.. I reemed out the PU bushes with a 16mm reemer, and suspension is moving with a small resistance now.
So.... just awaiting my beautiful new shocks from Darren 
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dozracing
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| posted on 7/5/03 at 03:18 PM |
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This is the method i'm using only slightly different, in that i'm attempting to take out the distortion effect as well. Sounds like you
have cracked it though.
What shocks are you getting?
Kind regards,
Darren
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Hornet
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| posted on 7/5/03 at 03:29 PM |
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well doohhh Im getting them from u 
Its john Baxter 
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ned
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| posted on 7/5/03 at 03:46 PM |
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the alternative is weld a length of round tube for the bushes to the wishbones and cut out the excess afterwards.
Andrew.
beware, I've got yellow skin
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stephen_gusterson
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| posted on 7/5/03 at 03:54 PM |
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you guys are using your real names and blowing your cover!
atb
Tarquin.
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dozracing
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| posted on 8/5/03 at 06:19 AM |
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Hi John,
You confused me. Didn't recoginise the handle, and the way you worded your reply made me feel like you were talking about another Darren!
The only way i can think of improving the distortion is to tack each part, then fully weld one bit, break the tacks and reset them, fully weld the
next bit etc etc.. Its how we do F1 wishbones. You can keep distortion down to about +/- 0.5mm this way.
Kind regards,
Darren
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