First, make sure the reservoir is full with the right dot fluid. The '84 used dot 3. With side bag off, open the bleeder valve to make sure it is loose and then tighten it. You need two people for this. Have the other person pump the rear brake a few times and then have them hold the pedal down, then you open the bleeder to let all the fluid and air out, the pedal will now go lower and make sure the other person keeps the pedal all the way down till you close the bleeder. It would be good to attach a rubber hose to the bleeder and catch the fluid, as not to make a mess. Do this several times and then check the pedal. Make sure to top up the fluid each time.
My owners manual for my 1984 Honda GoldWing says to use SAE 10W-40 Oil.
The '84 and '86 are the same. If you have the carb. version, why not. It's a manual cruise.
No reverse was not available till 1988 GL1500
100x90x15
regular fuel will do. 89 octane
4 plus over drive Total of 5
1984 to 1987 same engine same bike.
Most likely a dead battery.
best to replace it then bleed the brakes
Look for it on the steering column.
It should hold 22 Liters, or 5 us gallons.
I use SAE 10-40 takes about 3.2 liters. You have a dip stick also.