190E abs pump blister, internal failure?

[mikeohart]

During a recent arcing plug wire replacement I noticed the pictured blister on the bottom pipe (but looking from top) of the ABS pump. Can't tell from the picture as I brushed it a little with my finger but the exterior was shard (sp?), like a superhero puncturing metal with a screwdriver from the inside.

As I think about it, symptoms:
-brakes a little soft (but the car is 20 yrs old).
-when light application to a stop, slight hiccup of pressure can be felt in pedal a second or two before stopping, consistently at this point before stopping

But otherwise stops normally.

Anyone ever seen this before? Am I looking at total ABS pump failure and replacement?

TIA
Mike
'93 190E 2.3