A model 3508-34, How to deal with the brakes, any manuals and or good pics specs, etc. I'm guessing they are not wet brakes because the cap specifies DOT 3, it has leaky wheel cylinders I suppose. I just don't want surprises removing the wheels they are solid tires, never worked on these before.
You can post in the forklift section. @TD24 I think is a forklift guy. @CM1995 / @willie59 / @digger242j maybe one of those guys can move this to the forklift section.
I think @tractormech is a forklift guy too, hopefully one of those guys can shed some light on your problem.
A pic of the truck would be helpful to know/see what we are talking about. The complete model and serial number line off the data plate is necessary. Because... 3508-34 does not tell me anything about a Hyster? The DOT 3 ref indicates a master cylinder? The comment of solid tires leads to be a cushion tired truck... Tho Pneumatic design trucks can have solid tires. So. A WAG is; you have a 3 to 8K cushion tired Hyster forklift, like 18 x 8 x 121/8 solid tires, with about 6 or 8 bolt heads showing in the center. If so, jack up, remove the bolts, remove the wheel, tire, brake drum, as assembly and look at the shoes, wheel cylinder, etc. If an older truck, NAPA prolly can match the shoes and the wheel cylinder will have a number, probably Wagner. Any details will be helpful.