Adapting 405 Wishbones To The 205 Subframe?

[B1ack_Mi16 67]

Anyone thought about adapting 405 arms to the 205 subframe before?

 

I was comparing one to a 205 arm today and it seem that the front bush housing is pretty much the same as on the 205, so will probably be a straight fit.

 

The rear bush on the 405 is located too far backwards, so at the position where the 205 bush should sit there is more or less a square section of the forging. See pic.

 

Was thinking of maybe drilling a hole in that square section and fastening some kind of bearing to attach it to the rear of the 205 subframe. Only problem is that the rear subframe bush-mounting-point would need to be moved a bit inwards which I have not looked into if will be possible or not.

 

Secondly, on the 205, is it the front bush that takes almost all the shear force from accelerating and braking, while the rear takes most of the bending moment forces? Or is it more a 50/50 split on the shear force distribution?

The 405's rear bush will take more or less no shear force, just forces due to moment.

 

Asking because I'm wondering how sturdy the rear mounting will need to be.

 

Reason for why I'm concidering it is that I really like the replaceable bottom balljoints on the 405 hub carriers whoich would be bolt on with these arms.

[petert 588]

Wow, that's a great idea and the brightest spark I've seen in the world of 205's for a long time. In the end, it's all just metalwork, so if there's enough room, modify the 205 subframe to take the 405 mounts/arm. I'm going to have a look myself on the weekend. I'd much rather have a 405 balljoint on the race car. I've seen what happens when the 205 joint lets go in race conditions and it's all very ugly. The driver was lucky to tell the tale. Car a total write off.

[Rich_p 23]

I think Sandy's 309 runs either 306 or 405 wishbones, Sarty's 205 didd too I believe. it's been discussed on here before.

 

IIRC it required the subframe being altered along with part of the chassis being cut away to allow more room.

[welshpug 1,658]

it was 306 wishbones, they looked much easier to make fit than 405 ones, though still no small task.

 

Means either a replaceable 306 balljoint can be used, or a 405/6 hub carrier+balljoint and a custom plate with a tapered pin hole bolted in place of the 306 BJ.

[B1ack_Mi16 67]

Indeed, I have bought a set of 306 arms too, but they are far too wide and chassi leg needs to be modified. And these can't be rebuilt as safely as you would have to weld in a new tap etc.. don't count so much on my welding skills

Not sure the ARB will fit either using the 306 ones, with the 405 ones the ARB seem to have enough space at least.

 

I have been thinking even more now..

 

I think lynx engineering sells bearings instead of the bush on the 306 arms.

 

The rear bush/bearing from the 306 can then be used on the 405 arm. If I just chop off the part (cylindrical tap) where the 405 rear bush used to be, and then machine a new tap out from the square forging section of the 405 arms. Should not be hard for a machine shop I guess..

Then the arm would be more or less in its standard form and should have factory strength without any uncertainties like dodgy welding etc.

 

This way the front mounting point will be straight fit (which it isn't with the 306 arms).

 

And the rear point will sit further forward so one would not need to chop and weld the chassi-leg.

 

The length of the arm from front bush center to balljoint-hole seem to be 10-20mm longer than on the 205 arm, so it will more or less be like a 309 length-wise.

[omega 82]

cant help but watching with intrest.

[engine killer 6]

With the exchangeable balljoint, will you also consider the possibility of the roll-centre kit built in?

[B1ack_Mi16 67]

Didn't really think of that Enginekiller... If you mean spacing the balljoint down by an extension piece the threads in the hub-carrier will have to carry a much larger bending-moment than they were designed for due to the extra leverage, it sounds dangerous. It would be a more secure solution then to weld in new mounting points on the subframe slightly further up.

 

It seem the square section of the arm is 31mm high and approx 30mm deep.

So the far easiest way to be able to fit it to a standard subframe would be to drill a hole and fit a rose-joint.

I guess 31mm thickness is enough to put a large enough rose-joint into place?

 

What size rose-joints are usually used for the 205 wishbone configurations?

 

The other solution by machining a new tap and fitting a 306 rear bush will require a slight extension of the subframe, as the rear mount on the subframe sits a slightly bit too far inwards if the caster angle shall be kept more or less normal.

 

Maybe first try is to use a rose-joint and just drill and tap a hole.

[engine killer 6]

I was a complete failure on just spacing the balljoint down. So I am thinking of welding an extension to the hub carrier to space it down.

 

I have also been thinking about the 405 hub carrier with arm. It seems too difficult for me especially we can rarely find any 405 here.

 

I guess theoractically by having longer arm and tie-rod (both extend the same amount), the length difference between arm and tie-rod remains (absolute value), but the ratio gets smaller. This will result in LESS bumpsteer especially for lowered car, correctly me if I am wrong.

[B1ack_Mi16 67]

Not done much more on this, except found out that Citroen C5 wishbones also might be an option.

 

Need to try to get my hand on some to take some measurements. They are utulizing the slightly larger balljoint than the 405 (same as the 406 I believe).

[Kev-G 1]

Sub-frame is steel, so easiest option would be to move front mount forward (gaining some caster) and make a new mount up for the rear.

 

406 hubs would give you the same off-set as the 205 (405 would require 10mm spacers) and allow you to use 205 struts I'm pretty sure (never actually placed a 205 + 406 together).

 

Another option I had in my head was to use 307 hubs + struts....You're gaining caster with the wishbones while the 307 hubs could be modded slightly to take camber bolts + give you ajustability there.

[B1ack_Mi16 67]

Found out the 406 wishbones actually seem to add some caster due to the fact that the front mount sits slightly backwards relative to the balljoint hole.

Then it's possible to gain caster without rewelding front mount..

 

[B1ack_Mi16 67]

I started looking more into the wishbones today.

Have 306, 405 and 406 one.

 

 

I don't like the 306 one as that means I will need to modify the main steel brackets on the subframe that will take a lot of the loads.

Front mount is so wide.

 

Se how the 406 arm will give extra caster compared the the 405 one.

 

 

Have started to modify the subframe to see if things will fit.

 

The rear mount I have chopped off completely.

The front one I have cut away some parts of and found out that the 406 bush is slightly too wide to fit, but I trimmed the inner steel pin of the bush slightly with the angle grinder and managed to get it into place.

This can be sorted out by mounting some custom poly-bushes I'm sure.

 

 

I need some help with ideas on how to fasten the rear of the arm properly.

The cylindrical tap need to be chopped off as it is too far to the rear.

 

 

 

I'm not sure how to connect the rear, I guess somehow by using a rose joint.

 

What size rose-joints are used at the rear of 205 arms normally?

[B1ack_Mi16 67]

I moved the bolt hole on the front mounting point approx 10mm up and 10mm out btw.

[omega 82]

i ve been thinking about this and im sure that one of our overseas members did this to a fast 205 [was it someone in austrailia?] done a search but cant find anything.

[allanallen 528 2 Cars]

Have you looked at the 406 uprights yet? I think you'll need to considerably lengthen your wishbones to get the wheel in the correct position. 

'If' you could mount a 406 hub straight onto a 205 you would have a massive amount of positive camber.

 

The balljoint is a fair bit closer to outside of the hub on a 406.

[welshpug 1,658]

yes 405/6 hubs go straight on, that's what Colin Satchell has used with 306 wishbones.

 

would be interesting to compare the lengths of the wishbones form pivot to BJ, and as above take into account the different axis from damper to BJ and the distance the the hub flange.

[calvinhorse 870]

yes 405/6 hubs go straight on, that's what Colin Satchell has used with 306 wishbones.

 

would be interesting to compare the lengths of the wishbones form pivot to BJ, and as above take into account the different axis from damper to BJ and the distance the the hub flange.

 

406 hubs on 306 bones with a spherical bearing?

[welshpug 1,658]

no, standard BJ and a special plate with the tapered hole for the BJ

[calvinhorse 870]

ahh always wondered that! i bet its very special

[welshpug 1,658]

that was Sarty's 205, revised steering rack height too, don't know any other details though or any of the reasoning behind it other than it all worked very well.

 

no ARB's all round.

[rallyeash 155]

seen colins front setups when i was down there before. afaik steering rack is lowered then the hub end has a billet spacer that a rose joint TRE bolts too, 406 hubs and 306 arms i think too

 

might invest one day but not this year

[B1ack_Mi16 67]

Ok, so there is a spacer between the balljoint and the hub to get the rollcenter higher?

 

I have measured some roughly values on a 406 and a 205 carrier now, it seem that there might be 0.5-1cm difference in offset of the balljoint location, meaning the 406 carrier would sit slightly more inwards than the 205 one with the same length arms.

 

Any ideas to how to modify the rear of the arm in a safe way?

I have been thinking of just chopping it off around where the tap starts and weld on a threaded square piece of steel and just mount a rose joint there.

 

I need to compare the 205 wishbone length to the 406 one to see if it will be any good, but I think it is a fair amount longer.

 

Maybe it after all would have been easier just to get the compbrake ones...

[B1ack_Mi16 67]

I have starting to think I'm doing this a little bit hard for myself.

 

After looking at lots of other 205 arms people seem to be welding threaded bars and just bolting there uniballs at the front of the arm.

 

So why not just do some angle grinder action on a standard 205/309 arm and weld the outer part of the 406 arm in place?

I guess that must be just as secure as the different types of wishbones that looks like this:

 

 

You think that would be an adequate solution?

Edited June 6, 2011 by B1ack_Mi16

[ifcho 0]

I don't understand why would you prefer the 405 setup over the 205 one? Could you please explain a little more?

 

I personally like the 307 hub setup, as it allows for an quick an easy camber adjustment with the bolts holding the strut.