timing chain covers

[Guest Anonymous]

in replacing my water pump two years ago, i broke off a bolt. some mechanics suggested that i leave out the broken bolt and putty it up with red silicon sealant; and it worked -- til now. during the time i acquired a replacement lower timing chain cover with a -- supposedly, new crank shaft seal. so i'm faced with removing and replacing the lower cover (and probably the removing the upper , too).

questions: are there any hazzards when i remove both timing chain covers (is the pan gasket likely to get damaged?) should the timing covers, and the water pump be siliconed? how many new gaskets are involved? should i play it safe and install a new crank seal (how hard is this to do?).

any help on this would be appreciated. i do most of my own work, but i could take this to a mechanic (i have a good local independent bmw mechanic); any idea how many labor hours would be involved?