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Old 10-30-2000, 05:07 PM
Ron D. Harriman
Posts: n/a

Not asking a question here; relaying a
personal experience instead.

Bled the brakes for the first time myself
on the 380SL. I typically do one circuit
at a time and check after each caliper.
(I use a Mityvac vacuum tool.)

Drained master cylinder res, refilled, went
to first wheel (psgr rear) bled it, closed
up, went to check pedal feel -- overtravel.
Spongy as hell. Arrrrgh! How did I get all
that air in there?

I blamed the Mityvac and futzed with it
until it was too late to futz. Today, I
checked the shop forum for leads. Instantly
found a note to the effect that there are
two sections inside of the master cylinder
reservoir, that interconnect at the top with
a tiny pinhole.

Filling section 1 doesn't get fluid into
section 2 unless 1 is all the way to the top,
according to those posts.

Checked this car. Yep. Empty section 2.

Filled to the top. Section 2 filled up
once I did that. Rebled. Firm brakes.

Two observations: (a) boy, you guys rock.
I would have probably had to have the SL
towed to a shop if I hadn't found that note.

(b) What are MBZ engineers smoking in their
off hours? Dumbest M/C reservoir design I
have ever seen. And potentially dangerous.
Safety critical systems should not include
stupid pet tricks. Obviousness, please!

I hope I haven't torn up the M/C seals
with the pedal overtravel. No way to tell
until it fails on me. At least this way
I can hopefully have someone else learn
from my experience.

Ron H

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