Top rear Arms modifications

[ian24ian]

The Rear Suspension Top Arms on my HB are going to foul the chassis rails when I get the car as low as I want, has anybody got any pics of modified rear arms they wish to post or suggestions on how they would do the mod??

[droopsnoot]

I can't visualise the problem, is the HB very different to the HC at this point? I'm picturing my project HC which has the top arm mounts inboard of the chassis rails and heading off at 45°to the rail, I can't see what would make them foul the rails though I can't recall exactly what the route is immediately behind the mounts.

Can you post a photo of the affected area?

[ian24ian]

Oh dear,The joys of not sleeping for 40 hours, Mr Droopsnoot, you of course are correct, The problem should read, Top arms hitting the floor, the bottom arms may be fouling the chassis at the front, I apologise for the misinformation,

[1972nail]

You need to be really low for the lower arms to touch. Here's an HB racer which is as low as you could ever want to go and the arms don't foul.





He's even modded the arms to make it lower!

[ian24ian]

Mmm, thanks for the pics, when we mocked the axle up in position on my mates HB, things were pretty close on full deflection without bumpstops, Perhaps I need to look again, Might just be covered in 5mm of underseal
Changing the subject slightly, For a racer, I cant see any lateral location for the axle, (FIA permitting) I know the top arms are triangulated, but is that enough??, I have every intention of fitting a Panhard bar on my car, if I can find enough space.

[1972nail]

Both Gerry Marshall's Viva GT and Old Nail Firenza did not have a panhard rod. The triangulated top arma are enough if they are polybushed. How ever the rally guys find that parallel 4 linking with panhard rod makes for more traction on loose surfaces.

Many people box in the full length of the open sise of both the bottom and top arms. I'm not a fan of that and neither was Bill Blydenstien. Reason? As the car corners it rolls to one side. Too accommodate this the arms have to twist slightly, the top arms more than the bottom. If they are fully boxed then they cannot twist. This means that the twisting action is transferred to the bushes and chassis mounts which they were not designed to handle.

Bill Blydenstien boxed the couple of inches at both ends of the bottom arms and the chassis end of the top arm. This stiffened the arm where it is most likely to fail but still allowed the twist on roll as originally designed.

[ian24ian]

I suppose rose joint at one end would help with if you stiffened the bars, i see where you are coming from with the bushes and boxing the bars, you will probably get a ARB action/reaction by having the bars open, not very tuneable tho, I have intentions of fitting a big front ARB, then, hopefully, dial out the understeer with a rear arb

[Magnum2300chris]

You need to be really low for the lower arms to touch. Here's an HB racer which is as low as you could ever want to go and the arms don't foul.





He's even modded the arms to make it lower!

Hi what is the rear dics and calipers off what is the kit can you buy or do you have to make

[ian24ian]

I dont know for sure, But the calipers look like Ford Cosworth style, if thats the case, they are available from other cars too, Mk3 Granadas had them, in vented and non vented versions, Escort Mk4? RS2000, a Lot of seriaras had them as standard, Shortest handbrake cable is from the escort RS,
Discs, I would be looking at FWD vauxhall discs, probably base model Cavs, and fitting kits for the Ford English and Atlas axles are available from Rally Design, which I would think would not be insurmountable to convert.
I have never done this conversion on a Vauxhall axle, but have done several Fords from scratch and a couple of Toyota axles

[Magnum2300chris]

I dont know for sure, But the calipers look like Ford Cosworth style, if thats the case, they are available from other cars too, Mk3 Granadas had them, in vented and non vented versions, Escort Mk4? RS2000, a Lot of seriaras had them as standard, Shortest handbrake cable is from the escort RS,
Discs, I would be looking at FWD vauxhall discs, probably base model Cavs, and fitting kits for the Ford English and Atlas axles are available from Rally Design, which I would think would not be insurmountable to convert.
I have never done this conversion on a Vauxhall axle, but have done several Fords from scratch and a couple of Toyota axles

Hi thanks i will look it to it i oney did on conversion years ago on a mk2 escort i had i used ford searra ones