Next is working on the Air over Hydraulic Brakes. Any insight on where to start, what steps to take? Currently there is no pressure to the brakes when I push down on them, but the hand brake works wonderfully. Should I check the master cylinder first for fluid or any other steps?
Before I put any of my big old trucks on the road I've replaced/rebuilt the entire brake system from top to bottom. This would include all new brake lines both steel and rubber. Rebuilt MC (new are no longer available) and new wheel cylinders (Rock Auto or NAPA). Send the booster out and have it rebuilt. Having the shoes relined and the drums turned. When done you'll sleep better knowing everything is in good working order and not 60+ years old waiting to fail.
Get the shop manuals...you need the 1955 manual and then the '56, '57, '58 and '59 Supplement's. They made changes each year and they show up in the supplement's...AOHB is in the '56 manual, by '59 the supplement manual is mostly service info.
Also trying to better understand the 2 gear rear. I have a red knob on the dash with a metal line that runs down to the bottom of the transmission. Is this to switch the low vs high transmission? If so there is a lot of slack in the line, is there a way to tighten the line up to ensure that the shift happens?
The red knob on the dash is more than likely for the PTO (fire pump). If you have a true 2-speed there should be a knob on the gear shift lever, if it's a black knob attached to a cable you have a vacuum shift with a GM Corporate rear, if it's a red knob you have an electric shift with an Eaton rear. Shifting the rear when you don't have a true load will cause the rear gears to grind. The way I drive my 2-speeds is to treat 4th gear HI range like overdrive...start off in 2-lo, 3-lo, 4-lo and then shift to 4-hi (If you have a 5-speed then go up to 5-lo then 5-hi).
Always park the truck in Lo range.
Looking forward to seeing what you come up with on the bed design!
Mike B
