Yes... rust/corrosion is usually the problem. The cylinder bores can become very pitted, making it hard to keep them from leaking, even with new seals, etc. The last time I was faced with this was on my 1800ES, which had sat for many years in storage. I simply bought a set of remanufactured calipers... from Pep Boys, no less!

Obviously, there is nothing wrong with taking the calipers apart and making a decision (rebuild or buy reman's) after you've had a look. Just don't toss the old calipers in the trash bin... you will probably be charged (maybe $3, maybe $30, depends on the company) per caliper if you don't have cores to turn in. I'm guessing a little, but you're probably talking less than $300 for all 4 remanufactured calipers. If so, that's relatively little cash for that much peace of mind.

Gary L.
--
1971 142E ITB racer, 1973 1800ES, 2002 S60 T5