Fitting a HR balljoint front end crossmember 

All HR Holdens had a far superior front crossmember than the EJ-EH in a number of areas. It is stronger, it has ball joints instead of kingpins, and it has the option of disc brakes to aid stopping performance. Add to this that it is dimensionally similar to the EJ-EH crossmember and it becomes apparent why it has always been popular as a good update for this model.

It is important to understand that the HR uses a different size rear wheel cylinder to the EJ-EH regardless of whether you will be installing drum or disc brakes with the HR front crossmember unit. As such, thought must be given to either installing a proportioning valve to adjust brake balance, installing HR rear wheel cylinders or a complete HR rear end assembly to ensure brake performance is as it should be. Note that the rear wheel cylinder size for the HR drum brake front is different to the rear wheel cylinder size for the HR disc brake front, and the two should not be interchanged. 

Before fitting any second hand component to your vehicle, ensure that any worn parts are replaced. In this case look at ball joints, springs, inner wishbone bushes, brake linings and wheel cylinders. Also carefully inspect the crossmember for cracks or other defects which may make the installation unsafe.It is assumed in this article that the EJ will be running an engine other than the original “grey” motor, and as such, it will be assumed that the engine has been removed from the vehicle prior to the following work being undertaken. Note that extreme care must be exercised if the crossmember is removed from a vehicle with the engine still in place. This practice is not recommended.

Remove the motor from the vehicle, or raise the motor and support using a recognised engine support frame. Raise the front of the vehicle and support the body on stands under the chassis. Make sure that the car is level and the stands are firmly in place.

Remove the front road wheels and disconnect the brake lines where they are connected to the flexible hoses. Remove the clips that hold the flexible hoses to the subframe. Remove the splash trays and anti-sway bar from the vehicle. Remove the drag links from the steering arms using a suitable puller.

Place a pair of trolley jacks underneath the crossmember, raise the jacks until they just take a slight amount of load on the front crossmember, and then remove the front outrigger retaining bracket and the four bolts holding the crossmember to the subframe. Slowly lower the jacks and draw the crossmember out from below the vehicle.

At this stage either a changeover crossmember must be procured from any of the various retailers (Rare Spares, Rod Hadfield), or a competent welder may prepare his own. First the outrigger must be carefully removed and replaced with an original one from the EJ-EH. The engine mounts must also be moved if you are doing a “red” motor. To make sure that the mounts are in exactly the right position, run a string around the four posts where the bolts go into the chassis on your original front end, and measure the distances to the original engine mounts from there. Then cut off the engine mounts from the HR front end and run a string around the posts. You will be able to work out from the positioning of the string where to weld the engine mounts. Accuracy is of the utmost importance. The outrigger and engine mounts must be securely attached to the crossmember by TIG or MIG welding in a professional and competant manner.

Place the modifiedcrossmember on the two trolley jacks, slide it under the vehicle and raise until it just touches the subframe and lines up with the rubber insulators. It is best to use new rubber insulators for the job. Fit the bolts, washers and nuts being careful to use the front metal spacers and rear spacers in their correct positions, as they are slightly different lengths. Refit the outrigger retaining bracket with new rubber insulators, and tighten all bolts as specified in the workshop manual.

EJ-EH steering drag links are made up of ball and cup fittings which are very prone to wear. Whilst the crossmember conversion is being done, it is recommended that the HR ball joint type steering linkages are fitted. The pitman arm and idler arm from the HR can be bolted directly onto the EJ-EH.

Refit the brake lines and bleed the system. At this stage you may need to work out where your lines will be if you are going to run disc brakes and a remote booster. Make sure you fit only the EH sway bar, as no other will fit. Otherwise fit a new heavy duty sway bar, made to suit EH application. Once the road wheels have been fitted, lower the vehicle to the ground. If you need info on front brake applications to suit the HR balljoint front end, read on.