[68c10airstream]

Obviously the rear shoes need to be adjusted very close to the drums, otherwise all of the fluid motion is being used up just moving the shoes in/out.

A trick that never fails to improve the pedal feel is to jack up the rear of the truck as high as you are comfortable, then do the same up front. If you can get someone to do the jack work while you look at the fluid inside the master cylinder and watch for bubbles to rise up to the top. If you see the bubbles, you are on the right track. Another way to do this is to just unbolt the master cylinder from the booster and tilt it up/down as needed.

The other thing that happens a lot is pumping the brake pedal frantically. This will typically introduce air into the back end of the master cylinder. And if by chance the master is mounted uphill in the front you will frantically be putting air into the master that just gets trapped in the front uphill chamber.

Just move the brake pedal slowly as you bleed the lines. Remember this; as you release the pedal the only thing that keeps the lip of the plunger seal tight to the bore is how much tension is left in the rubber cup. Now throw in a rust pitted bore and you got the idea!

Another tip is never bottom out the brake pedal when bleeding because if the master cylinder has some mileage on it crud will migrate and get pushed forward, and when bottomed out this crud will move through the system. Not ideal!

If you think you have air in the rear another trick is to pinch the flex hose at the rear axle area and if the pedal improves your trouble is in the rear brake area. Pinching the flex hose isn't ideal but if desperate oh well.