The Mk2 clutch is cable operated, no hydraulics. Which gears are you having problems with?
If its first, reverse & fifth then the problem you have may be that the heat from the exhaust is making the relay shaft bush 'soft' which makes side to side movements of the stick less effective, it probably means the bushes are pretty knackered. Have a look in the 'mk2 maintenance and info' section at the gear linkage repair guide, there's loads of info in there.