On a sunny day last April, Mel B and I decided to sort out his saggy front suspension problem on wife Sandra’s yellow Manx buggy. Its always best to have everything you need to hand before you start, and to the uninitiated that’s the time to READ the manual, and get some insight into what’s involved. Mel’s problem was that the (linkpin type) front suspension leaves had given up, caused by metal fatigue or whatever after 38 years of bouncing up and down its hardly surprising. A replacement secondhand set (you need 2 sets, upper & lower) were purchased.
Firstly loosen the wheel nuts on both sides and then jack the buggy up making sure that it is well supported and cannot fall. Remove both front wheels to expose the discs or drums. Remove the nuts holding the steering track rod ball joints to the axle assembly, then using a decent ball joint separator, split the tapered ball joint from the arm. Never do this without a proper separating tool, as all you will do is compress the threads when bashing it out with a hammer and or damage the assembly. Once separated swing the steering tie rod out of harms way and secure it.
The torsion leaves are held in place inside the beam by 4 large grub screws and locking nuts. Loosen the lock nuts on both sides of the suspension arms and remove the grub screws with an allen key (piccie top right). Next, it may be necessary to use a soft mallet or lump of aluminium and hammer to persuade the torsion arms out. However do not use excessive force, they can be wiggled up and down and slowly creep out. Be aware that the flexible brake lines are delicate and must NOT be stretched when the arms are nearly fully out of the beam. It may also be necessary to split the brake pipe joint from the chassis to enable the brake pipe to be removed from the drum back plate or disc caliper.
Take care when at this stage, once the brake assembly has been removed from the beam, put to oneside. Unlock the 2 centre grub screws that retain the torsion leaves in the centre of the beam on top and bottom and remove them. The leaves are fed through a square hole that is the same shape as the pile of leaves, this centre boss inside the beam is the fixed point that the leaves work on. With the torsion arms removed from both sides, the leaves can be removed by pulling them out by hand.
Note the way round they are in relation to the beam, there will be wear marks on them from the years of use. You will see that the front edge of the leaf has a shiny wear mark caused by years of rubbing on the central fixed boss. These wear marks are useful for comparing to the wear marks of the replacement leaves if they are secondhand. The replacement leaves do not want to be installed upside down as over the years the steel will have a ‘set’ in it as a result of twisting in one direction. I would not recommend fitting the pile upside down as they may break after a while!
One point to note is that the leaves are dimpled with a drill when manufactured, and MUST be fitted in the same position they were drilled otherwise the grub screw will not seat correctly.
Once the new leaves have been examined and are oriented correctly gently separate them and cover all over with a liberal amount of grease. First insert the two smaller bottom leaves and slide them into the beam and through the centre fixed boss. I find it a lot easier to do it this way, as the remaining leaves, one at a time, can be used as a guide into and through the centre boss. When both sets of leaves are installed, line up the 2 centre drilled dimples with the grub screw holes and refit the grub screws and lock nuts. If necessary fit new rubber beam seals onto each torsion arm, then grease and slide the brake unit/torsion arms back into the beam, wiggling up and down to orient the square hole inside the arms with the stack of torsion leaves. It may be necessary to use a soft mallet to help things along, do not persuade the arms to slide all the way into the beam, as they stop short of fully home, and the grub screw dimple lines up with the holes. To ensure the dimples are in the centre of their fixing holes in the arms, use an electrical screwdriver. Insert it into the grub screw hole and if the dimple is somewhere in place you will feel the taper of the dimple as the screwdriver end slides down and finds the centre. All that is required is to hold the screwdriver square with the grub screw hole. If the dimple is to one side or other, the screwdriver will not be sticking straight down the centre of the grub screw hole. Just move arm gently until it is, then refit grub screws and lock nuts and tighten.
The leaves of the torsion bars are arranged differently dependant upon suspension type. In the (pre-65) linkpin models there are four large leaves and four small ones arranged in a “square” stack. The ball-joint models have the leaves stacked in a pyramidal shape.
