30 August 2010 – Rear Suspension – Phase IV

Work was slow on the car the last couple of weeks due to work scheduled over weekends, luckily I’m fortunate enough to take the hours off that I work extra in a month, this enabled me to take a full weeks leave from the amount of hours I accumulated. I arrived on the farm on Monday 30 August of a very busy race weekend. The Saturday we had a Gymkhana in the rain, what a fun day, and to add very informative, the Sunday we attended a track day with the Escort to provide my friend Ruan, which is now working in Zambia, with enough fuel in his blood to last him awhile.

Work started with the mounting the lower sub frame to the chassis. First we started with the tubing that would vorm the main mounting point between the chassis and rear suspension. It was shaped in such a way that we could use it to mount the upper wishbones, but also kept the design in such a way that I will still be able fix a rear anti roll bar and a box big enough to fit the fuel cell, surge tank, pumps and filters. Once these where done, we positioned the lower sub frame in place, after a lot of measuring and moving it around to get it in place we struggled with keeping it there, we decided to temporary fix it to the chassis, we tacked a pièce of angle iron in place and used a few C clamps to keep it from moving. This kept us busy for a the first day.

A piece of angle steel was added to the rear of the main tubing frame to keep the outer edges in place and to act as a mounting place for the rear differential mount. Work then moved on to get the lower sub frame mounted to the main tubing. The rear tubing was measured, cut to the correct angle and the ends which formed a whole due to the angle was fixed with welding a pièce of metal over it. After the rears was tacked in place we moved to the two in front which would vorm the mounting between the upper tubing and the front of the lower sub frame. Once these were in place, we were in a position to remove the temporary fitment of the rear sub frame to the chassis and remove the unit which is now one. We removed to complete unit and placed a temporary pipe to limit the amount of pull on the metal due to welding between the front mounting as we were going to do allot of welding as everything was just tacked welded in place. Another two supports was added between the main differential supports and the main upper tubing, we then proceeded to add some supports in the front made from pipe to keep the front mountings in place and limit any sideways movement. We proceeded to make the another two pièces if tubing which we added to the top of the main tubing, just above were we will be mounting the upper wishbone to allow us to create a cut out for the driveshaft’s to move in on upwards travel of the wheels.

In my free time, which was not allot, I managed to get some free time to make some inserts, the same as we used on the lower sub frame, which will be added inside the tubing to keep the metal from deforming when the wishbone adjusters is tightened. The rest of my time was used to make the pièces for the adjuster brackets. That night I was able to trial fit the upper sump plate that was lazercut. Day two concluded.

Unfortunately on the Wednesday and Thursday we had to do some work at the holiday home. At the end of the day it worked out very nice as we had some time to think and do some planning while we were focusing on other work. On arrival the Thursday evening back on the farm we started to weld the whole frame and installed the rear inserts in the tubing. This kept us busy for some time.

Day three started with a planning session around the possible solutions of mounting a rear anti roll bar, this kept us busy for a while, a solution was found and we set of to make the brackets, after these were done we finished the wishbone adjuster brackets and made another set of brackets to fix the center of the suspension to the chassis to aid with the weight distribution between the mounting points and the brackets was welded in place. The cutouts for the driveshaft’s was the next order of business, these were measured and marked. After the cutouts was made we closed the holes in the tubing with sheet metal plates made to fit and welded in place. The wishbone adjusters was fastened in place and the rest of the evening was used to design the upper wishbone. Again a endless amount of measuring equipment was used by my father to get to a design that the both of us agreed on. I’m pretty sure he has a secret fetish for measuring equipment.

Day four was set aside for building the upper wishbones. I started the morning with measuring out the design of the previous night, cutting the angles which would be used to keep all the pipes and outer tubes in their place. We started the building with the camber adjusters as this was the easiest. We used a 20mm metric fine bolt and had bushes made with the same thread. We welded them together and then proceeded to make gussets for the top and bottom to add some strength to the units. A vast amount of time was used to cut and grind all the pipes for the wishbones to the desired profile to enable them to fit snug around the outer tubes. When the welding was done we moved onto the inserts for the front wishbone adjusters. We assembled the top wishbones and first stood back to admire what we have just done. We assembled the rest of the suspension and checked verified that there is no strain on any parts during up and down travel of the uprights. With 50mm of upwards travel from ride height, the suspension design offers us 3.4 degrees of dynamic camber. It seems that we can use a very similar design to this for a off road rally vehicle due to the amount of travel that it provides us with. The downside to this is that I will need to install straps to limit the amount of downwards travel in order to keep the shocks from not getting damaged. We installed the suspension back into the car and fitted a 14” wheel which is just slightly higher than the racing tires the car will use primarily. It became very apparent that flares will be in order and that I will need to cut the rear arches to get some môre travel if I want to benefit from the advantages of Independent Rear Suspension. I was in such good spirit that I fitted the 14” Cyclone rims to see how it would look, I like the old school feel to it. The rest of the evening was used to find a solution to get the shocks mounted. We came up with a plan that I think would look and work the best. at the end of the day.

Day five was used to admire and celebrate our achievement and get the final shock mount plan on paper to enable us to order the metal needed. On my next visit the shock mounts will be finished, this will enable me to get the necessary measurements for the shocks, then I can order them and wait while they enjoy their trip over the water. Hopefully I will also have time to measure the prop shaft in order to get that made.

More Pictures – 30 August 2010 – Rear Suspension – Phase IV

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