Your master cylinder should be replaced. Get a new one. If you have a booster, replace it as well.
Also check the vacuum pump, as worn seals will cause oil to migrate to the booster and ruin
the internals. Thought this would be easy?? Check your brake hoses while your at it. I had
a problem with the liner inside the hose (right front) that acted like a check valve. Someone on this
forum suggested that, and was correct.
Bench bleed the master cylinder prior to installation. Be sure you get a bench bleeding kit with the
MC. They are plastic and may not work well. I bought a couple of pieces of metric brake tubing and
made my own, which made the bench bleeding much easier.
Parts are available from the usual suspects that advise on this forum. NAPA had the brake hoses in stock,
and they were Semperit brand. Also had the front brake calipers. Otherwise I used a local MB parts house
in Oakland, Ca.
Rebuilding the vac pump is easy. Keep track of how things come apart, take photos as you go along. There
is a vid on YouTube.
From: diesel_mercedes@yahoogroups.com [mailto:diesel_mercedes@yahoogroups.com]
Sent: Friday, August 14, 2015 8:18 PM
To: diesel_mercedes@yahoogroups.com
Subject: [diesel_mercedes] Brakes
I have a 1980 240 D with a manual transmission. The car sits most of the winter, and the Pennsylvania winter was very cold. After driving the car in the country for a while, say longer than thirty minutes the Brake petal just goes away, No petal. I changed the rear Caliphers and lines with a used set of caliphers. It worked fine for a few days and then it came back. After stopping, with out hitting anything. :-) The petal slowly comes back and the brakes are nice and hard. I do not think it is a vacuum problem, because the petal goes to the floor. I have not been able to find any rebuild kits. thanks for any help bob k.
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