Guys,

I did a Google search on brake hose failures and found a write up that says using different brake fluid types and brands can cause the rubber to swell so much it seals the pressure inside the caliper. First time I heard of that, but, if it is true it would explain why I have never expererienced it. I use Castrol GTX LMA fluid, exclusively and have never had a brake hose problem. I have had seal aging issues though. The write ups also suggest there should be visible signs of distress, including some weeping of fluid at the metal end connections (edit).

I still find the concept that the hose can swell so much that it forms a perfect seal in one direction but not the other (edit) hard to understand. In any case, it is probably not a bad idea to change the hoses at the same time if you use a variety of brake fluids. Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)