For this car I am lucky enough to have a complete set of front and rear suspension by Proflex. proflex are one of the leading manufacturers in Europe If not the world of competition suspension systems.
The standard Corsa brakes are headed for the bin and will be replaced at the front by larger discs and calipers. The rear drum brakes have also been scrapped in favour of a disc brake conversion.
But first lets look at the rear beam. I have removed this from the car and added strengthening plates at each side to reduce the risk of bending should I have a brush with a kerb or similar solid object. I have also welded heavy steel strip around the bush mount tubes, as these will be fitted with heavy duty nylon bushes and will take a fair bit of punishment. The steel strip is a bit over the top but its all I had!!!!
Converting the standard drum brakes to VW Golf discs is quite a straightforward job. The first step is to remove the hub castle nut and take off the drum brake cover. Next remove the entire hub assembly by undoing the four 10mm bolts (antiTorx head) from the back of the mounting flange. Now take the stub axle and place to one side, then chuck the rest in the bin!!! After cleaning up the stub axle the new VW disc brake can be assembled. You can see from the picture above that my car will have a 50mm wide steel spacer which is convenient for welding a caliper mount bracket to. The only tricky part of the assembly is the need to manufacture a small washer (see pic) which is used to space out the inner bearing(and therefore the whole thing) by 5mm. The only reason for this is to prevent the castle nut from running out of thread when it is refitted and nipped up (Take care not to overtighten!). Its very handy that the Golf Disc and bearings fit exactly on to the Corsa Stub and the road wheel bolts directly on to the brake disc.
The caliper Im using is supplied by Compbrake and is basically an Audi TT single pot sliding caliper with the all important built in handbrake mechanism. Its a requirement to have a cable handbrake even if you also have a hydraulic one. This photo shows the hub and brake assembly, you can also see the cardboard template for a caliper mounting plate. The whole thing will be attached to the beam using 4x 80mm M10 x 1.25(fine pitch) high tensile cap screws which are very strong.
In this next pic you can see the assembled parts (minus caliper). The caliper bracket has been welded in place along with two steel spacers to correctly align the caliper with the disc. I had manually clamped the caliper to the disc using the handbrake mecahnism to ensure it was sitting square before welding the brackets in place. The caliper will be held on with 10.mm x 1.mm x 40.mm high tensile cap screws
The front suspension Is a little more complicated than the rear as I am fabricating my own bottom arms and tie bars. The standard rubber bush type mounts are binned as is the standard bottom ball joint which is a known weak spot on Nova's and Corsa's. A failure of the bottom ball joint can be pretty catastrophic and can result in a very big accident, so its really essential to upgrade or replace the standard items for rally use. For the bottom arms Ive used high quality 30mm diameter x 3mm thick cold drawn seamless tube (CDS). A steel threaded insert is welded into either end to accept the 5/8 heavy duty rod ends. The overall length is 35mm longer than a standard arm. This is the same amount that the top mounts have been moved outward as part of the wide track mods. At the outer end two steel 'cheeks' are fitted to attach the forward tension strut and a cut and welded bend has been made to allow sufficient clearance of the rod end when the suspension is on full droop (The point when the shock absorber is fully extended, such as over a jump)
The forward end of the tension strut is attached using a standard mounting bracket which I have modified by cutting out the center tubular bush mount and welding in square section steel tube, this is drilled vertically (10mm) and a high tensile cap screw holds the Rod end in place, a pair of top hat spacers keep the rod end centrally mounted and allow free movement in any direction. I chose to use the standard bracket as this effectively guaranteed that the front mounting of the bar was exactly right in relation to the rear pick up point. It also means that the three standard bracket fixing points are retained in the front crossmember.
