Well the trusty 300d is acting up again. 2-3 times in the past week I went to use tha brakes and the pedal went much lower than usual the the brakes were very weak, almost causing a wreck. 99% of the time, the brakes work as they should.

I checked all the caliper and lines, all is good, no leaks and the brake fluid level is good.

This leads me to think there is something wrong with the master cylinder. The thing is, it was replaced it just 2 years ago.

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1985 300D : the clean one 180k miles - Now passed onto my parents.
2000 E39 M5
2002 e46 330xit
1991 mustang notch (project)
1970 chevelle (project)

Yep, bad master cylinder.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Is it common for w123's to have MC's fail on them this often?

__________________
1985 300D : the clean one 180k miles - Now passed onto my parents.
2000 E39 M5
2002 e46 330xit
1991 mustang notch (project)
1970 chevelle (project)

No. Probably a poor rebuild.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Stop driving the car until you figure out what is wrong and fix it.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

The car is on stands as we speak.

__________________
1985 300D : the clean one 180k miles - Now passed onto my parents.
2000 E39 M5
2002 e46 330xit
1991 mustang notch (project)
1970 chevelle (project)

Just be glad your gas pedal isn't getting "stuck" like them 90% plastic Japanese cars

X3 with the master cylinder. Had the same thing happen to me within months of replacement, now im on my 3rd and it's working fine, so far.

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http://i106.photobucket.com/albums/m...73378_30-1.jpg