Brake bleeding woes

1976-1985: 230T, 230E, 230TE, 230CE, 280E, 280TE, 280CE, 240D, 300D, 300CD, 300TD,
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mathuisella
Adenauer
Posts: 362
Joined: Sun 08 Jun, 2014 7:03 am
Model you own: w123
Location: Brisbane, North side.

Brake bleeding woes

Post by mathuisella » Fri 10 Nov, 2017 6:20 pm

I've tried bleeding the brakes, but they still feel so spongy, not sure what i've done wrong. I've followed this video
https://www.youtube.com/watch?v=n1NvtUwfRJc

I done each corner seperately, jacked it up, took the wheel off for better access.

Cleaned the threads with a brass wire wheel, put teflon tape so it would stop leaking through the threads and sucking air back in.

some pictures
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tsharkey
C 111
Posts: 881
Joined: Sat 25 Apr, 2009 10:32 am
Model you own: w123
Location: Melbourne, Vic

Re: Brake bleeding woes

Post by tsharkey » Sat 11 Nov, 2017 11:35 am

I skimmed through the video and it looks like the old pump the pedal method.

I would make up a pressure bleeder to get all the air out of the system as that appears to be what is causing the spongy action.

Others on this forum have made one using a bike pump connected to a valve drilled into a spare cap. Pump in some air to create pressure and then bleed a wheel. Just what your reservoir levels !
W123 1981 300TD - Family Kid mover
W202 1998 C250D Factory OM605A Turbo - Partner's daily driver
W123 1982 300CD Retro fitted OM617A Turbo - Mine
W123 1984 300TD 5 Speed Manual, to teach the kids how to drive
W123 1982 300TD Factory OM617A Turbo (Hans) - Project
W123 1985 230TE - Brother's
W123 1985 300D - Sister in Law's
1962 S-Series Valiant (Tho Daimler & Chrysler divorced, still part of the extended family)

Past benzes
W114 1969 250CE - PO put in an M110 transplant and nearly sent me around the bend
W123 1981 300TD - "Matilda" - RIP hit front side & rear but left my brother + niece A-OK

Current Projects
Coupe restoration, Turbo Wagon freshen up

nea100
C Class
Posts: 48
Joined: Wed 09 Dec, 2009 5:16 pm
Model you own: w123
Location: Mackay Qld

Re: Brake bleeding woes

Post by nea100 » Sat 11 Nov, 2017 12:02 pm

Hey Mathuisella,

Have you bled the master cylinder? Make sure no air has found its way in there first.

Could try undoing each bleeder and leave and let gravity drain new fluid (with air) through. Then maybe some gentle pedal pumping into a bottle of fluid to finish off. Hopefully the calipers are in OK condition?

Had a lot of trouble with the old Valiant following full brake replacement, and after much bleeding, much bleeding that is, ended up using a pressure bleeder to pump the air out, that got it! Best way if you are working on your own.

Good luck.
1984 300D - Gold, Gold, Gold
1984 280CE - Silver Blue - Undergoing minor restoration
1970 Valiant VG VIP - White - Distant relative

tsharkey
C 111
Posts: 881
Joined: Sat 25 Apr, 2009 10:32 am
Model you own: w123
Location: Melbourne, Vic

Re: Brake bleeding woes

Post by tsharkey » Sat 11 Nov, 2017 3:44 pm

Forgot to ask ... Why did you need to bleed in the 1st place (because you had to change the Master Cylinder reservoir for the clutch ?). If some other reason presume that cause was cured.
W123 1981 300TD - Family Kid mover
W202 1998 C250D Factory OM605A Turbo - Partner's daily driver
W123 1982 300CD Retro fitted OM617A Turbo - Mine
W123 1984 300TD 5 Speed Manual, to teach the kids how to drive
W123 1982 300TD Factory OM617A Turbo (Hans) - Project
W123 1985 230TE - Brother's
W123 1985 300D - Sister in Law's
1962 S-Series Valiant (Tho Daimler & Chrysler divorced, still part of the extended family)

Past benzes
W114 1969 250CE - PO put in an M110 transplant and nearly sent me around the bend
W123 1981 300TD - "Matilda" - RIP hit front side & rear but left my brother + niece A-OK

Current Projects
Coupe restoration, Turbo Wagon freshen up

mathuisella
Adenauer
Posts: 362
Joined: Sun 08 Jun, 2014 7:03 am
Model you own: w123
Location: Brisbane, North side.

Re: Brake bleeding woes

Post by mathuisella » Sat 11 Nov, 2017 4:36 pm

Okay so a friend helped me do the 2 person method. Build pressure, hold pedal and release valve, close valve then rebuild pressure. Repeat until all air bubbles come out and pressure is good.


The reason i needed to do this was 2 fold.

1. I had no idea how old the fluid in the system was and whether it was the more common dot3 instead of the required dot4 liquid.
2. When i done the clutch, the factory manual said to connect the slave cylinder up to the front right brake caliper, which i did, however, i believe this introduced air into the brakeline system, whether it was carelessness from my end or not it happened and the whole thing was a failure.

I ended up doing the 2 person method for both the clutch as well as the braking system. Brakes seem quite adequate now :)

thank you for the questions, tips, replies :) much appreciated.


Both my clutch and brake system are completely flushed of old liquid and using blue coloured DOT4 liquid now :)

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