Well, it starts out with pulling the harmonic balancer. On my 58, I got rid of(actually, removed) the radiator, grill and bumper. More on why a bit later.
Once the balancer was removed (using a commonly available puller from my local FLAPS), then remove the bolts on the timing cover. It helps if you remove the fan and pulley on the water pump, makes it a bit easier to get to all of the bolts for the cover.
Once the timing cover is removed, scrape both of the gasket surfaces for the cover, and remove the old front seal. This can be pulled out easily with a pair of side cuts. I repainted and cleaned the cover at this time.
If you have a complete gasket set, it will come with a new front seal and a cork spacer. The reason for this spacer depends on the condition of the harmonic balancer shaft. It will likely be deeply scored at the position where the old seal rode.
Good time to have the harmonic balancer rebuilt, by the way. I used Dale manufacturing out of Salem, Oregon, very pleased with the results, and quick turnaround. Check the links page. I polished the harmonic balancer shaft once it was returned. The re-builders will generally clean the shaft with emery paper, I wanted a smoother surface for the new front seal.
Place the cork spacer in the timing cover first (optional, remember it depends on the condition of the balancer shaft) and then the new seal and drive the new seal into place (I used a block of wood with the cover resting on the tool bench). Make sure that it is aligned to the cover and is level with the cover all around.
Now you are ready to replace the cover. I used the standard GM gasket sealer (GM Gasket Sealing Compound) for the cover gasket. Place all the bolts back in the cover and leave loose. DO NOT TIGHTEN. In the next step, you will need the cover to be able to move about.
Now for the harmonic balancer. Place two 5/16 X 1 inch bolts in the balancer where previously you had placed the puller bolts. Tighten these, this will prevent damage to the rubber components in the balancer. Take a small amount of assembly lube (there are a lot of folks who will tell you to use nothing), lubricate the front snout of the crankshaft and place and lightly drive the balancer onto the end of the crankshaft.
Now, depending on your truck, you need a direct line of contact to the harmonic balancer which is in the axis of the crank. Thus the removal of the sheet metal mentioned above. The reason for this is that you need a straight line of attack to make sure that you are driving the balancer back on straight. Place the water pump pulley back on and secure with its bolts. Leave the fan off for now.
I use a 2X4, the end of which I placed against the balancer while a friend with a BFH (a large hammer, for the uninitiated) hit the other end. Using the water pump pulley as a guide as to how far to drive on the balancer, just keep driving on until it is visibly aligned. (Others may have a more accurate method to suggest later). The balancer felt as if it bottomed out at the correct point anyway.
Now tighten the cover bolts. The cover will now be aligned with the seal and crankshaft once the balancer is in place. The repair manual calls for 6-8 foot pounds for the cover bolts, do not over-tighten. Remove the two 5/16 bolts from the balancer, and reassemble the rest of the truck.
Hope this helps, I just finished this project on my 58. It sealed up nicely.
