kingr
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| posted on 10/6/03 at 08:49 AM |
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Front Suspension - What's the verdict
Put my front suspension on the car for the first time last night, and I'm pretty pleased with how it looks. The top and bottom wishbones are my
own design - the bottom is modified to accept an Astra mk2 ball joint, and the top is modified to give 6 degrees of castor with the brackets fairly
central on the tubes. I used the design that I have rather than as shown in the book to allow more room for the shock.
So, any comments or observations would be gratefully recieved (well, probably  ).
Kingr
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kingr
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| posted on 10/6/03 at 08:50 AM |
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pic 1
 
Rescued attachment front suspension 3_small.jpg
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kingr
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| posted on 10/6/03 at 08:50 AM |
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full compression
 
Rescued attachment full compression 1_small.jpg
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kingr
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| posted on 10/6/03 at 08:51 AM |
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full droop
 
Rescued attachment full droop 1_small.jpg
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timf
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| posted on 10/6/03 at 11:45 AM |
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Just one question
on the bottom wishbone have you got a link between either side to assist in torsional loading or are you just using the ball joint mounting plate to
hold them
apart from that question looks good m8
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kingr
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| posted on 10/6/03 at 12:38 PM |
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Yes, just using the mounting plates - although I haven't done any analysis on it, I've got no reason to think that it would be any weaker
than the book design, infact, it should be significantly stronger - the book tells you to crush the tubes, mine are left uncrushed and mount the ball
joint in between. You may not be able to see from the photo, but the ball joint mount is angled so it is positioned going from the bottom to the top
of the tubes (sorry, I know I'm not being very clear but it's quite hard to explain). Surfice to say it certainly wasn't the easiest
shape in the world to chop out of 3mm plate steel!
There are more photos in my album, so have a look there if like.
Kingr
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Viper
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| posted on 10/6/03 at 04:54 PM |
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nicely painted etc but where are you going to mount the shock???
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MikeRJ
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| posted on 10/6/03 at 09:07 PM |
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The only concern I would have is that the Astra used McPherson struts, so the balljoint was never designed to take the kind of loadings it will get in
this situation. There was a problem with these fracturing (or was it Cavs?) a few years ago when garages were jacking up the cars using the lower
suspension arm.
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Mark Allanson
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| posted on 10/6/03 at 09:22 PM |
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It was the track control arm itself that used to crack, they used to do it all by themselves without the help of a clumsy jack. The were made from two
pressings spot welded together back to back and used to chatter together and fatigue crack. We used to change them for the modified ones as a matter
of course if even the slightest risk that the arm was damaged in an accident, the insurance companies did not wantthe risk of a recently repaired car
having an accident due to failure and the subsequent litigation. I never came across a balljoint failing, even if the wheel had been torn off.
If you are the slightest bit worried, keep checking for play, I am sure they would wear before failing
Mark
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craig1410
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| posted on 10/6/03 at 10:56 PM |
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Just make sure that the bolts securing the bottom balljoint are of the highest grade you can get. 10.9's minimum with 12.9 strongly recommended
and torque them up according to the recommended torque for the the size and grade.
They look good though.
Cheers,
Craig.
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kingr
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| posted on 11/6/03 at 11:37 AM |
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Thanks for all your comments, I'll reply in order :
Viper - Yup, I noticed that too, just after I'd painted them (doh!), so I'll have to strip and area around where the brackets will be
mounted, mount the bracket and hope the heat doesn't knacker the rest of the paint too much.
Mark and Mike - Thanks for the warning and explaination - I would have checked them periodically anyway, but it's nice to know it wasn't
that part that failed!
Craig - The bolts currently holding them on are 8.8s but I've got some 10.somethings that came with them, so I'll use them once they being
put on permanently.
Kingr
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kingr
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| posted on 11/6/03 at 11:39 AM |
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One more question - what size hole do I need in the bracket for the shock?
Kingr
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stephen_gusterson
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| posted on 11/6/03 at 01:02 PM |
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depends on the shocks you are gonna buy.
mine are 10mm....
atb
steve
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craig1410
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| posted on 11/6/03 at 04:39 PM |
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I think the GTS shocks are 1/2 inch and these are the ones I'm planning to buy.
Cheers,
Craig.
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8smokingbarrels
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| posted on 1/7/03 at 06:26 PM |
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Strut your stuff!
Kingr- great photos of your suspension- is the upright from an Astra as well?
If so, did you have to do a lot of work to it to accept the balljoint of the upper wishbone. The reason Im asking is that i got a couple of Audi
struts but they are one piece and will require a bit of work to accept the top balljoint.
Thx for any help
chris
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Rorty
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| posted on 2/7/03 at 01:27 AM |
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Is it my imagination, or does your set-up change from neg camber in bump to a large amount of pos camber in droop?
If so, what happens to the outside wheel in roll, and what are the track variances involved?
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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kingr
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| posted on 2/7/03 at 08:37 AM |
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Hi Rorty + 8smokingbarrels,
Thanks for the comments,
8Smokingbarrels - The uprights are from a sierra, and the adaptors are from loloquality I don't know whether they would fit an audi though,
other people have made their own adapter though - cutting down the old mcpherson strut and welding a taper into that is one way.
Rorty - The suspension movement you can see is pretty big, a lot bigger than it's ever going to be on the car also I think the photos are a bit
deceptive, it looks like a lot more movement than there is. As I'm sure you're aware, going from one extreme to another is going to
produce massive camber changes compared to those in the comparatively small actual working area. The design of the suspension is barely different from
the book, the only difference being in the positioning of the top ball joint which is slightly further back due to design of the upright. I worked out
the difference in camber change before hand, and it was tiny IIRC, I'll work it out again, just to be sure though. A shorter top wishbone will
result in greater negative camber during compression, which is unlikely to result in disaster. Thanks for the interest though.
kingr
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kingr
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| posted on 2/7/03 at 08:42 AM |
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Sorry, just to clarify, the top ball joint on a sierra hub is slightly further away from the wheel. "back" isn't much of a
description at all. The lolo adaptors have an angled taper to put the ball joint slightly further towards the wheel than they might otherwise be.
Kingr
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