Gbs Wishbone Kit

[Guest clive5550]

Hi all I've finally grown a pair and my sliding pillar set up is in a heap on the garage floor thanks to my grinder !, I've got my wishbones and hubs trail fitted and I've got coded welder coming to do the work. My question is has anyone got any measurements or hints on how to get the top and bottom wishbone brackets in the correct positioning for my castor angles, the camber and tracking can be adjusted after.I've read previous posts saying that I need between 3 + 7 degrees of castor but I need to get my positioning correct thanks Clive

[Guest mower man]

Biggest thing is to get things aligned to the vehicle centre line and that wheel base is eaqual also that pick up points are eaqual giving a mirror image to each other . Basic angles should be in the region of castor 3to 7 degs pos camber 1 to 1.5 degs neg toe in as little as possible ,definitly no toe out .Ride height should be set first !!! [ v imp] with possibly a little rake i.e.slightly higher at the back as this affect all angles .Try to give a little clearance on top w/bone to allow caster to be adjusted by moving the bone backwards or forwards by shimming .Are you using the sierra bottom arm or a wish bone? if you are using the sierra arm you will need to make up tie bars and throw the a/roll bar in the skip[ I can send you details of tie bar set up ]measure twice or mor and cut once HTH mower man thanks for the like

[knights_templar]

Unfortunately the 2B chassis is not a mirror image side to side so you can't use it as reference.

 

some take the ref from the rear axle centre lines, but as these move, The best reference is the each end of the subframe, you need the front track to end up parallel to the rear.

 

 

you can calculate the position of the top bar in relation to the lower but the easiest is to use the replacement side panels as templates

[Guest SteH]

Clive, some pictures of the steps involved in this conversion would be brilliant. This is something I want to do soon.

[Guest clive5550]

Biggest thing is to get things aligned to the vehicle centre line and that wheel base is eaqual also that pick up points are eaqual giving a mirror image to each other . Basic angles should be in the region of castor 3to 7 degs pos camber 1 to 1.5 degs neg toe in as little as possible ,definitly no toe out .Ride height should be set first !!! [ v imp] with possibly a little rake i.e.slightly higher at the back as this affect all angles .Try to give a little clearance on top w/bone to allow caster to be adjusted by moving the bone backwards or forwards by shimming .Are you using the sierra bottom arm or a wish bone? if you are using the sierra arm you will need to make up tie bars and throw the a/roll bar in the skip[ I can send you details of tie bar set up ]measure twice or mor and cut once HTH mower man thanks for the like

thanks Mick I'm using wishbones on the bottom as well, when you say to leave clearance on the wishbone I've got some movement in the the front mounting bracket but the back one is tight so there would be no movement back and forward there its difficult to find a starting point for measurements.

[Guest clive5550]

Unfortunately the 2B chassis is not a mirror image side to side so you can't use it as reference.

 

some take the ref from the rear axle centre lines, but as these move, The best reference is the each end of the subframe, you need the front track to end up parallel to the rear.

 

 

you can calculate the position of the top bar in relation to the lower but the easiest is to use the replacement side panels as templates

I thought that about using the panel as a template but when I tried to set up the bottom wishbone I lined up the front bracket and when I fitted the wishbone it fouled actually touching the rear of the wishbone on the chassis

[Guest Ian & Carole]

One tip when you start welding get a long length of 8mm treaded bar and push through both the brackets and wish bone. to ensure the is no twist when the wish bone move up and down, if that makes sense.

[Guest mower man]

thanks Mick I'm using wishbones on the bottom as well, when you say to leave clearance on the wishbone I've got some movement in the the front mounting bracket but the back one is tight so there would be no movement back and forward there its difficult to find a starting point for measurements.

You need that movement suppose after thinking [dangrous ground ] you could move the bottom bone instead if it helps . If your want to veiw the definitive on this obtain Alan Staniforths book Competition car suspension from Haynes and spend aweek or two on read,mark and inwardly digest mick

[Guest Ian Maycock]

I changed mine over last year. On removing the sliding pillars I found that the off side was 15mm further back than the near side. I used the centre of the rear wheels and measure forward equally to get the same wheel base on both sides.

On setting the castor don’t forget that the sierra hubs have a certain amount of castor already built in. I forget what this is but it can be calculated by using an engineer’s protractor. I built in the ability to adjust between 3-7 deg by using wider top mounting brackets and then using washers as shims this way if the position on both sides is not exactly the same you can adjust it after welding. The upper bones will be slightly further back than the lower one. As mentioned the best thing to do is get four lengths of screwed rod long enough to go between the two mounting points so that they are level and there is no twisting in the bones it is important that they are aligned correctly. I used a length of dowel the same size as the mounting tubes on the bones, a little interference fit is a good thing. I made 8 centre plugs. I then and drilled 10mm holes through the centres so that each single length of screwed rod would pass through the centre line. I then held it all together with nuts to stop It sliding around. This will also help to set up on a trial fit. I would advise tack welding all the brackets and do a trial fit of the complete set up measure the castor which should be at around 5deg at the midpoint so you can adjust +/- 2 deg if needed. Once you are happy then weld up. I must have tacked and moved my brackets 3 or 4 times before I was completely happy with their position. I fabricated my own mounting brackets as I didn’t like or want the large cross members that are supplied by GBS.

Don’t rush it. It will take longer than you think.

[Guest mower man]

Iggy thay post is brill !!! concise and to the point mower man

[Guest clive5550]

Iggy you are absolute star it starts to make some sense now finally thanks very much cheers Clive.