it's the nature of rubber and the interaction with hydraulic fluid and its interation with moisture
since all of the rubber parts are old, they all swell and bleed off pressure equally - old seals don't hold as much pressure as new ones - replacing one will then allow more pressure to go to the others, revealing any weaknesses - sounds weird, i know, but it happens way too frequently to be a fluke
in about 30 years of playing with this clutch hydraulic stuff, it has been my observation that about 1/3 of the cars that have changed only one component in the clutch hydraulics, rather than all of them, have had a failure almost immediately - that number went up to about 1/2 within a matter of months, and almost 3/4 over the first year
those staggering figures are enough evidence to me to say clearly that it is a very bad idea to cheap out and not buy the remaining 2 components, when the labor to get back in there is more than the parts themselves, let alone the tow home, and the mess to clean up from hydraulic fluid getting all over the place - that does not even get into the bar tab from all the kicking yourself you will do for not doing it right the first time
it takes very little more time to change out the master and slave, than to do just the hose itself, and the cost is very minimal - save yourself the headache
94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating
www.968forums.com
"It isn't nearly as expensive to do it right as it is to do it wrong."
