[W126 Coupe] Brakes and air

[Michael Ramay]

The check valve in the middle of the 1/2" vacuum line from the engine to the
brake booster is the normal failure point. Once that cracks/breaks and
vacuum is gone, the pedal goes from the normal "kinda firm" to "Rock F'g
Solid". A guy (LARGE guy) with both feet on the brake pedal *might* be able
to get the car to stop. My 5'2" wife has no chance.

FYI, this check valve is a part that should be looked at at least once a
year to see if the plastic is starting to look chalky. Doesn't hurt to
wiggle it a little bit too. IIRC, it's about $30 for the black tubing with
the check valve in there.

On Sun, Dec 19, 2010 at 11:46 AM, Jay Hirsch <J.Hirsch at mac.com> wrote:


> On "normal" cars,  to me which is  most American cars if the power booster

>  has  a "leak" the brake is very hard or firm,  and stays that way the more

> you apply pressure, something we all wish at various times

> Will not comment on the 560  power booster but  assume all brake systems

> are the same....spongy pedal either air  in the line or fluid  leak some

> where.

> Do not know why you  do not try the simple and fool proof way of bleeding

> lines

>

> Jay H

> On Dec 19, 2010, at 1:05 PM, Ronny 560sec wrote:

>

>  Jason,

>> I thought that when there is a vacuum leak the brake pedal will stiffen!

>> Or am I wrong.

>> Meanwhile I will ask my mechanic to check that line too.

>>

>> Ronny

>>

>

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