Banana
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| posted on 11/10/16 at 09:22 PM |
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MK Lower wishbone- Urgent
Im after a bottom front wishbone for an MK indy.
Seeing as MK don't seem to want customers, where am i supposed to get one?!
thanks
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CosKev3
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| posted on 11/10/16 at 09:34 PM |
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Could try the Scottish Kit Car centre,as they use MK chassis's for the Raptors they sell 
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Banana
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| posted on 11/10/16 at 10:07 PM |
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will do. ta.
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Banana
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| posted on 12/10/16 at 10:23 AM |
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Typical. They are just about to close down for 1 1/2 weeks..
Nobody have a 2nd hand one kicking about..?
Is it safe to get my original straightened do we think?
Images here..
http://www.locostbuilders.co.uk/viewthread.php?tid=205898&page=2
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nick205
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| posted on 12/10/16 at 11:46 AM |
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I'd not be comfortable with straightening it - it may well be weakened.
Can we ask how it got bent?
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Banana
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| posted on 12/10/16 at 12:21 PM |
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No idea. Ive only just got the car. Noticed it whilst i was pulling it to bits.
Spoke to Scottish Kit car - they dont have the outboard suspension wishbones.. Mk not answering the phone..
I would have thought the welds would give way before the tube, even if it had been pressed straight slightly..
Not ideal, but not sure what else i can do.
Unless someone has a spare?
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sdh2903
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| posted on 12/10/16 at 01:18 PM |
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Try contacting procomp or MNR to see if they will make you one. Or MAC1 as I recall their chassis being very similar to the MK
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AJC
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| posted on 12/10/16 at 02:25 PM |
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The bend doesn't look to bad. The tube should bend back quite easily if you can get it in a vice.
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rusty nuts
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| posted on 12/10/16 at 05:23 PM |
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quote:
Originally posted by AJC
The bend doesn't look to bad. The tube should bend back quite easily if you can get it in a vice.
Asking for trouble!
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Banana
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| posted on 12/10/16 at 10:27 PM |
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Has anyone made up some bracing/strengthening plates to go under their wishbones?
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CosKev3
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| posted on 13/10/16 at 07:21 AM |
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I do seem to remember early MK's having quite a few lower front wishbone issues,sure I've read about them on here.
I've got my original Mac1 wishbones in my garage loft,they are made from oval tube though not round.If you put up sizes of yours on here
I'll have a check if you want?
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Banana
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| posted on 13/10/16 at 09:05 AM |
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Yes ive read about MK wishbones being weak - so i was thinking of making some 3/4mm bracing plates to go underneath and reinforce the welded bosses.
Would have thought some others had done this..?
Thanks for the offer, will measure mine up when i get a chance. Mine are oval tube btw.
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sdh2903
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| posted on 13/10/16 at 11:14 AM |
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As you say There are quite a few reports of the early bones breaking. And in your thread shows they are rusty and now you've found a bend.
Rather than patching up and repairing would it not be a wise decision over the winter to just replace the set with the added strengthening?
The consequences of a bone breaking whilst out on a blat could be nasty, really nasty. I'd remove and replace do it properly. Just my 2
penneth for what it's worth.
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Banana
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| posted on 13/10/16 at 11:38 AM |
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Yes im making enquirers to get some made up. As it doesn't seem you can get these off the shelf anymore.
But even on my new set, im going to look at adding some bracing.
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40inches
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| posted on 13/10/16 at 12:47 PM |
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Would these fit? Rally Design
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Banana
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| posted on 13/10/16 at 02:36 PM |
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Good find!
Ive requested the drawing to compare..
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Banana
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| posted on 13/10/16 at 07:52 PM |
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Had a word with a local engineering/restoration company, in regards to strengthening the wishbones.
They proposed something along the lines of some 5 x 15mm bar welded sideways (on the 5mm face) along the underside of each wishbone arm and halfway
around the round bush tubes..
With some additional filleting in the center.
Id like to experiment with these wishbones, and implement the final design on my new ones.
Seems reasonable? Any thoughts or other ideas?
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Banana
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| posted on 13/10/16 at 10:52 PM |
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Checked the rally design ones, but they are a cm or so to small in all dimensions..
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CosKev3
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| posted on 14/10/16 at 06:55 AM |
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IIRC the issue is with the shock absorber mounting being too far inboard on the bone,so ideally this needs moving outwards so it's nearer the
ball joint.
I think what you suggest above will help,but there are thousands of kit cars on the road that have no issues with the wishbone strength,but with the
shock mounted too far inboard you put more pressure on the length of tube between shock mount and balljoint.
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Banana
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| posted on 14/10/16 at 08:07 AM |
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I thought the weak point was the welds holding the bush tubing on. As seen when the crush tubes seizes and can't turn.
Interesting what you say about the shock mounts, as protech seemed to think the angle was already a long way from upright, and possibly effecting the
effectiveness of the shock.
In my head, the shock mounted further out would increase the leverage and therefore the chance of bending the wishbone..
Would love to know if others have done any modifications in this area.
[Edited on 14/10/16 by Banana]
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CosKev3
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| posted on 14/10/16 at 08:14 AM |
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The bush tube only fails if the bushes are seized,no point strengthening the wishbone there,just keep the bushes healthy!
You want the shock to be mounted as close as possible to the ball joint, so the forces are not working against each other along that stretch of
wishbone between shock mount and balljoint.
The angle of the shock is probably far from ideal,but what other choice have we got?
Hence why a lot of newer chassis's are now push rod set up with the shock absorber in board.
[Edited on 14/10/16 by CosKev3]
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Banana
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| posted on 14/10/16 at 09:15 AM |
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Yep i see what you mean. Thanks for the input.
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sdh2903
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| posted on 14/10/16 at 09:26 AM |
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Just remember as well you don't want to make the wishbone mega strong, in the case of a bump with a kerb or armco you want the wishbone to
deform to protect the chassis. Just strengthen around the shock/balljoint mounting.
[Edited on 14/10/16 by sdh2903]
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ReMan
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| posted on 14/10/16 at 10:17 AM |
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quote:
Originally posted by Banana
I thought the weak point was the welds holding the bush tubing on. As seen when the crush tubes seizes and can't turn.
Interesting what you say about the shock mounts, as protech seemed to think the angle was already a long way from upright, and possibly effecting the
effectiveness of the shock.
In my head, the shock mounted further out would increase the leverage and therefore the chance of bending the wishbone..
Would love to know if others have done any modifications in this area.
[Edited on 14/10/16 by Banana]
The issue will also occur if the crush tubes are too short, and the bracket is clamping the bushes, which you
are obviously addressing
www.plusnine.co.uk
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procomp
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| posted on 14/10/16 at 01:53 PM |
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Hi.
As already suggested there is a design flaw with the basic design. Damper mounting being far to inboard from outer causing high loading on the
arms.
The other issue is even with the damper in that position it is at far to much of an angle also to be effective in control of the movements. IE
1" / 25mm of wheel movement = something like only 5/8" / 16mm of damper rod movement very very poor ratio.
I have in the past made new wishbones for a few MK owners with extension beams to move the damper out and give far better control similar to the wide
track conversions i make for Westfields.
Cheers Matt
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