Preparing the new double wishbone, coil over front suspension.

By Craig Ranson
By Craig Ranson

Managing Director – Bridge Classic Cars

This system was designed and is manufactured by hawk Cars and Hoyle Suspension Ltd.

MGB Coil Over Front Suspension

This new double wishbone, coil over front suspension system has been specially designed to overcome some of the criticism of the original or other alternative options.

The kit replaces some of the components normally fitted, there are:

  • The four front wishbone arms.
  • The two spring pans.
  • The lever arm shock absorber.
  • The bolts and nuts from shock absorber mount, top and bottom kingpin assembly.
  • The front coil springs.
  • The bump stop and spacers.
  • The anti-roll bar link arms.

The coil over shocks are specially made ‘click’ adjustable, rebuildable units with adjustable spring seats to enable to change the ride height of your car. The springs supplied are a standard 2 1/4″ ID which are used on a variety of special and race cars. These can be obtained in a wide variety of poundages and lengths. In order to be able to fit a full size spring shocker of this type it is necessary to modify the front crossmember in order to give clearance. We can do this for you by supplying a ready modified unit on exchange. If you wish to carry out the modification yourself it its necessary to cut a curved section from each end of your crossmember and weld in a gusset, this is supplied in the kit. The advantage of using your original crossmember is that it can be modified in situ.

Stage 1

MGBGT Front Crossmember

MGBGT Front Crossmember

MGBGT Front Crossmember

Stage 2

MGBGT Front Crossmember

MGBGT Front Crossmember

Stage 3

MGBGT Front Crossmember

MGBGT Front Crossmember

Off to the blasters…

MGBGT parts to be blasted

MGBGT parts to be blasted

Assembly Sequence

The special mounting brackets supplied have to be fitted to the crossmember in place of the original lever arm shock absorber.

It is essential to make sure that the threads in your crossmember are in sound condition. The brackets are secured using special high tensile allen bolts torqued to the correct setting as in the owners manual. We recommend you use ‘loctite’ for these.

The original lower wishbone pivots are retained, make sure that these are straight and in good condition.

The lower wishbones (straight ones) attach to the wishbone pivots using either MGB V8 rubber bushes or if you prefer we can supply special polyurethane bushes (which are of a special high grade material). Notice that two of the wishbone arms have threaded bosses to accept the anti-roll bar link arms, these go to the front of the car.

Note: the bushes on the inner ends of the wishbones will last longer if their retaining buts are tightened when the vehicle is at ride height.

Assemble the springs onto the shock absorber after first unscreing the adjustable seat (to its lowest positon). We always recommend the use of a coil spring compressor when handling these components. It is a good idea to put ‘copperslip’ on the threads and collars.

The spring shockers are assembled to the suspension with the adjuster facing the engine and using the special 12mm bolts and spacers supplied.

We suggest that you start with the springs wound fairly high to start with and if you wish to lower the car then make sure you don’t go too low and have problems with ‘sleeping policemen’ etc. the upper wishbones are curved and these are attached to the special mounting brackets in the same way as the lower wishbones and use the wishbone bushes. You will therefore need a total of eight new wishbone bushes altogether.

A new bolt is supplied for the top wishbone to stub axle the standard tapered bushes (or polyurethane) are used here. Please note that two special shim washers rebuked each side these bushes at the top, these are to enable the castor angle to be adjusted should you wish. There is also a special spacer that is fitted slightly inboard of this which increases the rigidity of the top wishbone assembly.

The bottom stub axle retains the original seals, thrust washers and spacer tubes etc, but a special bolt replaces the original item. The special high tensile bolt has a small flat machined on it which carries two snail cams, one under the bolt head and one under the nut. This enables the camber angle to be adjusted simply by slackening the nut and then rotating the bolt with an allen key. When you have set the desired chamber you must tighten the nut securely without letting the bolt rotate. Make sure that your bottom link parts are in good condition and kept well greased. If in doubt replace them – refer to owners manual if you need guidance on these parts.

The anti-roll bar link arms are replaced with our type, which are threaded to accept a special spherical joint. The spherical joints can be screwed up or down in order to set the anti-roll bar evenly and without bias. It is important to make sure that the joints are locked in place with a lock nut and that they are positioned carefully not to interfere or foul during operation. This can be checked with the shock absorber in place, with the spring removed, by checking clearance through the full suspension and steering lock travels.

Adjustments

To set up your suspension the car needs to have the full weight on the wheels. First adjust the ride height (easier to do if the car is jacked up and the wheel removed – yes I know we said have it on its wheels!!!) so that the bottom wishbones are horizontal (parallel to the ground), this will give you the standard height. This can be lowered if you wish, but the amount by which it is lowered will reduce the bump (upward) travel by the same amount. Secondly the chamber should be adjusted, for road use 1/2 – 1 degree negative is suggested. Finally the tracking can be set up to standard MGB spec – 1/16@ toe in. A good starting point with the shocker adjustment is ‘two clicks’ in and see how the car feels on the road. Increasing (turning knob clockwise) the number of clocks will make the shocker harder and vice versa. Keep increasing the damper setting until you feel the ride is too firm then drop it back a couple of clicks.

This system was designed and is manufactured by hawk Cars and Hoyle Suspension Ltd.

 

 

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