Bill,
The parking brake on my GMC 5500 is a handle about 16 inches (I am guessing) long that is mounted on the left side of the cab and pulls straight up. I have not seen any screw adjustment for the brake cable in the cab. I just got the cable unstuck (with lots of WD40 to be followed with a real lubricant) a few days ago, so am now trying to figure out how to tighten it.
Underneath, the brake is a shoe that goes around a hub behind the transmission. It is divided into upper and lower halves at a solid bar on the left side that is bolted to the transmission. There is a lower adjustment nut below a large spring on the lower, right side. This seems to mostly adjust the lower shoe. The upper shoe needs to be tightened, but I have not been able to find the adjuster for it. An experienced mechanic told me a couple of days ago that there should be an adjustment bolt or nut on the upper, left side of the tightening mechanism, but this is pretty much out of sight from below, and I have not had a chance to try to find it yet. I hope to take a look tomorrow, but not until after an appointment to have the VIN checked - so I will be turning the engine off to use it as a brake when opening and closing gates. I would be grateful for any advice about this.
