Bleeding master cylinder

1968 - 1976: 220, 220D, 230, 230.4, 230.6, 240D, 250, 250C, 250CE, 280, 280E, 280CE, 300D
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Raijin
C Class
Posts: 33
Joined: Wed 24 May, 2017 7:24 am
Model you own: w114
Location: Tweed heads NSW/ Gold coast QLD

Bleeding master cylinder

Post by Raijin »

Hi all
I got a new master cylinder for the 114 but having trouble bleeding it due to the 3 outlets. Unless i have a faulty master. When on the bench and pumping the cylinder i only get fluid out of the 2 front nothing from the single rear. The fluid in the resv only fills the front and middle i am assuming the rear chamber is for overflow.
When on the car and trying to bleed the peddle gows about half way the goes to floor with no preasure but when coming back up it gets stuck at the half way point for a bit then jumps up to the start point. :angryfire:

Any help advice would be awesome
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John Green
Mercedes Demigod
Posts: 7677
Joined: Mon 20 Jun, 2005 3:49 am
Model you own: w112
Region: Australian Capital Territory
Location: Canberra-center of the known universe
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Re: Bleeding master cylinder

Post by John Green »

It is a dual circuit master cylinder, front and rear are separate circuits. This is why the reservoir has two chambers. The idea being that if one section fails the other will still work.

The rear chamber should have fluid in it? Fill the reservoir to the brim and it should spill over into the rear chamber. I presume that you have cleaned out the reservoir, so that the old crap that would have been sitting in there, didn't go into your new master cylinder?
Kind regards, / Mit freundlichen Grüßen,

John Green, Member Institute Automotive Mechanical Engineers


http://mbspares.com.au - Supporting Australia's Mercedes-Benz Enthusiasts.
Raijin
C Class
Posts: 33
Joined: Wed 24 May, 2017 7:24 am
Model you own: w114
Location: Tweed heads NSW/ Gold coast QLD

Re: Bleeding master cylinder

Post by Raijin »

Brand new rez as well so all good there ok so thats where i have been going wrong have to get all chambers filled will do thanks for the tip.
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