Front Anti Roll Bar Bracket

[Martin V]

I’ve discovered that the mounting bracket on the passenger side of my GT6 MK3 for the ARB has a crack in it. 
 

I’m guessing that although it is a welded on bracket, the only way to resolve the issue will be removal and replace with a new one?

Any idea where to get the bracket? Or other solutions?

Edited Monday at 18:41 by Martin V

[Colin Lindsay]

Definitely not available, unless one turns up from old salted-away stock. Plenty of them about on rusty chassis, as long as you get a better one than the one you have. It could be welded in situ, if you're happy that any weld will hold in this area, especially as it has already cracked there once. A restorer-breaker like Chic Doig will be able to remove one with no damage, possibly even make a new one, so that you don't need to worry about removing your damaged one in one piece. Just grind the old one off and have the replacement welded back on. 

[JohnD]

?? http://spitfiregraveyard.com/

[Pete Lewis]

we dont seem to have seen this before  I wonder if this is just agism  or less compliant poly bush making  

some extra stress  ...........  

Pete

[Martin V]

Thanks. Spoken to talented friend and we are looking to press up plates to sit over the existing ones which avoids the need for removal from chassis and should be stronger when two plates fixed together.

[Mjit]

Are you sure the metal's actually cracked and it's not just the paint that's flaked?

I don't think these brackets take any real load do they?  When one wheel loads one end of the ARB the two chassis bushes are meant to let the bar 'rotate' and pass the load over to the other end of the ARB/the other wheel.  It's not like the P/S chassis bracket's meant to solidly clamp the ARB and be the point the ARB 'bends' against.

[Martin V]

19 hours ago, Mjit said:

Are you sure the metal's actually cracked and it's not just the paint that's flaked?

I don't think these brackets take any real load do they?  When one wheel loads one end of the ARB the two chassis bushes are meant to let the bar 'rotate' and pass the load over to the other end of the ARB/the other wheel.  It's not like the P/S chassis bracket's meant to solidly clamp the ARB and be the point the ARB 'bends' against.

I’ve checked again. Looks like a split crack with corrosion showing. The bush bolts are just the tightness in the WSM so it should be working correctly in and corners. If this torque still stands?

Definitely on its way out in that passenger side. The crack edge can be felt as a sharp edge when running finger nail over surface. The top front edge of plate can be seen as not straight (as it is on DS). Rear  plate edge is even more obviously distorted showing how it is twisted.

I’ve just slackened off the clamp to look closer but now wonder if the clamps are too tight for the latest tech bushes? 
 

I also seem to remember that the ARB comes with a twist in it. Can anyone verify this? I’m sure I’ve read this before so even on flat ground there is tension across the ARB length. This is odd from my racing car history as usually they are flat. Anyone know the merits of this?

[Martin V]

22 hours ago, Pete Lewis said:

we dont seem to have seen this before  I wonder if this is just agism  or less compliant poly bush making  

some extra stress  ...........  

Pete

Pete, extra stress for myself when I thought all was good. Purely chance spotting as I looked at my anti corrosion prep.

I’m wondering what could be causing this. I think when I refit the bar I’ll check if can rotate in the bushes but I’m sure I checked that previously.

[johny]

6 minutes ago, Martin V said:

I also seem to remember that the ARB comes with a twist in it. Can anyone verify this? I’m sure I’ve read this before so even on flat ground there is tension across the ARB length. This is odd from my racing car history as usually they are flat. Anyone know the merits of this?

Noooo Martin dont open that one!

[Mjit]

Yea, sounds like it really is cracked - but then it was only meant to last what, 5 years? and has been on there for 50.

If you are/know a good welder I'd be tempted to just drop the ARB, clean things up adding a "V" to the crack and just weld it up.  Done properly the weld should be stronger than the surrounding steel.

[Martin V]

Ah ha…believe I’ve spotted the cause of the issue. When these have been welded in, guessing at restoration the welding job has been very poor on PS plate. From the photos you will clearly see 1cm or more longer weld across full width of chassis rail. 
1cm less weld means more flexible plate length (more leverage by the ARB) and hence bending until cracked!

So no I think we bend it back, weld properly and I think we will plate both plates equally to give strength and secure PS fully from cracking further.

Not keen on cutting the weld line, I’d rather add metal not risk chassis joint.

new pics from rear of plates….guess which is Passenger side!

Edited Wednesday at 13:03 by Martin V

[JohnD]

TBQH, that weld quality could easily be OE!

And, does your second pic above show the bracket to be bent?   Any other evidence of impact in the past?

The idea of cutting a Vee into the crack is to ensure a full penetration weld for the repair.   Otherwise the weld metal will only be on the surface.   Also good practice to drill a hole at the extremity of the crack and weld into that, but difficult to do that in this situation.

John

[Martin V]

2 hours ago, JohnD said:

TBQH, that weld quality could easily be OE!

And, does your second pic above show the bracket to be bent?   Any other evidence of impact in the past?

The idea of cutting a Vee into the crack is to ensure a full penetration weld for the repair.   Otherwise the weld metal will only be on the surface.   Also good practice to drill a hole at the extremity of the crack and weld into that, but difficult to do that in this situation.

John

Thanks John. Yes second picture is bracket rear edge also showing how the twist of the ARB has bent the plate with the extra length of flexible plate. I doubt OE as it wouldn’t have lasted the mileages. 

Thanks for the drill hole tip, we did just that to halt a cracked OD mount plate earlier this year whilst sorting a replacement and fitting.

My friend is a highly skilled constructor so I’ll watch and learn when it comes to making the strongest solution. I think he’ll have ideas on improving both plates.

Below is the stripped down plate after a little cleaning up. It shows a large gap has opened up between chassis and plate. In other side of car the centre part of plate touches the chassis! Perhaps some light hammering might be required legitimately this time!! 

 

[Martin V]

9 hours ago, johny said:

Noooo Martin dont open that one!

It’s actually almost flat!

[Josef]

3 hours ago, JohnD said:

TBQH, that weld quality could easily be OE!

I agree, they look more like gas weld than MIG and there’s no sign of old weld / old plates in the area. Gas makes it more likely to be factory, and lack of any remains of older bits of chassis makes it less likely to be a bodge over (unlikely someone cleans up perfectly then does a half arsed welding job)

[wimpus]

I've seen this a lot on Spitfire 1500's , as the anti roll bar is thicker.

Mine have been welded a few times.

I do need to find a way to re-make those plates, as i need to fix a Spit 1500 where its fully broken off..

[johny]

16 hours ago, Martin V said:

Looks like a couple of flat mild steel strips of the appropriate thickness, each with a hole for one of the U bolt fixings and then poked in between plate and chassis would reinforce it with no welding required?

[Martin V]

1 hour ago, wimpus said:

I've seen this a lot on Spitfire 1500's , as the anti roll bar is thicker.

Mine have been welded a few times.

I do need to find a way to re-make those plates, as i need to fix a Spit 1500 where its fully broken off..

Will let you know if we press some up. Original plan was to press couple of “piggy back” plates to fit over the top. Will decide later if that’s still needed.

[Josef]

18 minutes ago, wimpus said:

I do need to find a way to re-make those plates, as i need to fix a Spit 1500 where its fully broken off..

I think they’d be able to be DIY formed on a press or hammer form. They’re thick metal, but for making one or two making a buck out of something like oak should work. For something longer lived I might try and make a metal press tool. In both cases the alignment of the work piece and the tooling is made easier but the four holes needed in the final pieces!