Volvo Repair: B234F seals, shaft seals, balance shaft

Question
I'm doing a cam and balance belt on my 90 740 with B234F 16 valve.  Can cam seals be changed without special tools or is there cautionary info I should know before starting?  Same question for oil pump and balance shaft seals.  Do you recommend changing all seals even if not leaking?
Thanks
Mike

Answer
there is a tool to check belt tension if the belt is too tight it will be noisey.if the timing belt is installed wrong the valves will get bent when starting the car.I would replcae all the seals while you are in there.there are special tools to install the seals but they can be put in without them if you are careful.