The rear brakes get exposure to a mucky enviroment because the adjusting slots are elongated and the rubber bungs are missing or part of the backplate has rotten away I know people think im strange for trying to put everything back to standard but vw wouldent waste money on parts that were not needed for a reason
I find a spray of wd on the bolts of my van then a breaker bar and off they come not saying that is the case with every bus .
been unlucky enough to shear lots of bolts and had to drill them out, the worst were some m20 head bolts on an old rolls royce engine after snapping about ten of them we scrapped the thing. had to get the cab bolts out on a caterpillar d5, all sheared, couldnt scrap the cat so spent a couple of days drilling them out( yaaawn, best tan i ever got in that quarry ) copper greased up the new ones and fitted so they would be easier to remove next time. used a lot on big machinery if an m8 bolt snaps in no big deal try getting out m24 m30 etc, bit more of an issue. all the parts vw fitted would have been oiled when fitted which will help with stripping at a later date, but corrosion gets in eventually.but greasing hubs is generally a no no as the grease can push out and cause wheels to fall offf.
Coppaslip has a high solids content (the copper bit), so works well under high load conditions like on threads. The problem is, anything that needs to be torqued up will be dramatically over tightened if you put coppaslip on (reduced thread friction means that for a given torque the tensile load will be higher), risking the thread stripping. Also, anything you really want to stay tight is at more risk of working loose. Threadlock is always a better option - stops things from coming loose and also keeps any water out of the thread.
I like a bit of coppers slip on threads as well. The problem with normal grease is that it's just oil held in suspension, eventually it dries out or washes off in certain applications. Hopefully the copper should remain and act as an antisieze compound.
