Yeah, we didn't have to remove the mast. We got the housing off and it was the brake shoe. We just removed it since we just needed to unload it to free up the trailer. Aside from needing to replace a hydraulic valve it seems in pretty good shape for $400. It is electric by the way. Thanks for the help.

Just looked at thread again after looking at some info i have....is this an electric EC500 or a gas/lpg C500 series? You haventhe full model number....the electric and the gas/lp use some what diffrent brake setups based on truck and truck size....the electric and larger trucks use an internal brake sytem as well and come apart similar to what i described..but instead of being a conventional looking brake shoe it is a disc type brake with a friction disc that is riveted to a disc and a brake actuator assembly that has three"hockey puck" style brake pads in it..lis a real PITA brake system...

Just looked at thread again after looking at some info i have....is this an electric EC500 or a gas/lpg C500 series? You haventhe full model number....the electric and the gas/lp use some what diffrent brake setups based on truck and truck size....the electric and larger trucks use an internal brake sytem as well and come apart similar to what i described..but instead of being a conventional looking brake shoe it is a disc type brake with a friction disc that is riveted to a disc and a brake actuator assembly that has three"hockey puck" style brake pads in it..lis a real PITA brake system...

No the mast dosent need to be removed to get to the brakes on these trucks....sounds to me like you just removed the outer plantary hub and not the whole axle end....the brakes are internal to the drive housing and actually face backwards from what they are on most other teucks and vehicles....to remove the axle end there will be a seies of bolts and studs around the perimiter ofmthe axle end...bolts on the forward portion and if you raise the mast and look at the back side you will see the studs and nuts that come thru to the back....these axle ends weight upwards of 100 plus pounds and are eccentric so will be a bear for one person to man handle.
First remove the bolts that are on the fwd front/outboard section the heads of the bolts will be in the neighborhood of 1 inch plus...then remove the nuts on the backside with the mast raised AND BLOCKED to keep it from falling....
In my opinion if youve never done a brake job or work on the front end of one of these it would be best to have a technician do it....

Also if you do try and go it by yourself...onlynremove one side at a time...removing both sides can cause issues with the center section dropping out of place.....

We first thought it was the brakes, we took the planetaries off to see, but couldn't get to them from there. The way it looks now, we will need to take the mast off to be able to get to the brakes. We don't have the service manual, but does the mast need to be removed to access the brakes?

Everything is made more difficult since it's still on a trailer. Our plan was to charge it (and it took a charge fine) then drive it off, but it won't drive forward.

How about the lining came off one of the brake shoes and it it sliding and jamming going forward? I've seen that before. Jack it up and figure out which side it is.