Is this brake master cylinder shot or is there some kind of seal that needs to be replaced?

Thanks

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1980 300TD(euro non turbo): Eng: 617.912 /Tran:722.118
1985 300SD: Eng: 617.951/Tran: 722.416

Looks like.
There is an obvious leak at the shaft. Probably some inside the booster too.

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83 SD

84 CD

They sell Master Cylinder Rebuild kits but they cost close to what a rebuilt Master Cylinder Costs. Also, If the Bore inside of the Master Cylinder is Pitted there is no point in rebuilding it yourself.
There is also a solid Pin or a Roll pin that you can see if you pull off the Reservoir and look into the Forward hole. That pin goes through the Master Cylinder Piston and needs to be removed before the Piston can come out.
Anyway, that is the type of Master Cylinder that is on mine.

The Chilton Manual shows 2 types of Master Cylinders. On has some Extra Valves on it and that one looks like it is easy to take apart.

I bought a Rebuilt from what was Kragen Auto Parts. I did not work entirely well but I left it on the car and it lasted about 1.5 years.
I bought an entirely new Master Cylinder From Auto Zone for $63 (the price went up a few months later) made by Fenco and it has worked good.
When I found my Paper Work I did go back and get another Rebuilt one under warranty but did not use

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84 300D, 82 Volvo 244Gl Diesel

Good info posted already..
replace the MC and be sure the booster is in good shape before installing the new one to it...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

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

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

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

I can you tell if a booster works?

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

I had a problem a few yrs ago, where I had to replace fluid every once in a while. didn`t have the fogyest idea where it was going. I finally pulled the MC, and the booster was about 1/2 full of fluid.

So not knowing what damage the brake fluid would cause to the booster, I just replaced booster and master cylinder. a little pricy, but it is MY safety Iam concerned about, and not interested to cut corners with the brakes.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

A very hard pedal that requires a lot of pressure to stop the car is the symptom of a bad booster. You can replicate the problem by removing (and plugging) the vacuum hose running to it. Do this in a driveway or parking lot.

To the OP, it sure looks like a failed M/C. As others have posted a new one is the way to go. You can try cleaning the booster ,inside and out, of brake fluid with denatured alcohol. Re-paint the exterior, otherwise nasty rust will result.

That master cylinder is leaking badly! They only cost about $70 to replace...however, your booster is probably done too.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Oops, I meant out of the car. I got it with a bunch of other parts. It's a bit rusty, so it at least needs to be repainted.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

I am going to order a MC from fastlane. I'll see how the booster looks like before spending $350.

I appreciate everybody's help.

Thanks.

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1980 300TD(euro non turbo): Eng: 617.912 /Tran:722.118
1985 300SD: Eng: 617.951/Tran: 722.416

I have had cars in the past where there were kits to fix the rubber in the Brake Booster..
all I remember is that it involved being sure there was plenty of talcum powder on it when it was installed...
I do not know if one is able these days to take it apart, examine, clean and reinstall...
But you do need to find out if the MC leaked INTO the brake booster...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

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

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

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

I know its been mentioned a couple times already, but I destroyed a brake booster (and to this day i have a sneaking suspicion that also messed up a auto tranny) by unknowingly allowing the BB to fill with brake fluid. I was 20 yrs old though and thought my calipers were leaking (one was leaking for a while).

My point, if your BB is very full of fluid, make sure the REST of the vacuum system doesn't have traces of brake fluid in it!

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'82 240D 224K miles manual transmission
mods: wooden 4by4 bumper, EGR delete and older EX manifold without EGR port, glass pack muffler (cheapest replacement muffler), rebuilt bosch injectors with Monark nozzles

working on: aux electric fuel pump, coolant/fuel heat exchanger/filter head, afterglow, low oil pressure buzzer/LED

This is pretty comprehensive 'Brake Booster' article PDF file (from Lexus technical training) and I have exactly same problem as page 10&11 described.

http://www.autoshop101.com/forms/brake05.pdf

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'86 560SL - 110K
'84 300D - 280K
'81 240D, 4speed - 320K
'74 240D, 4speed - 130K - just sold
------------------------
2000 DiscoveryII - 90K
1997 Saab 900S - 190K

The leak looks like the same leak that happened to me a while back.

The master cylinder actually was ok but there is a seal that was chewed up that goes between the cylinder and the booster.

Just get a new booster, they are cheap and have everything you need to get the job done. Make sure you do some searches on bench bleeding the new one with your new fluid before you take the old one out. This may be a good time to fully bleed your brakes as well.

As far as the booster, you probably have some brake fluid in your booster. Get a turkey baster and suck out the old fluid, unless you have to use excessive force to stop the car its probably not bad. If you do end up needing one, check around. I would never pay 350 for one. I went to my local checker auto parts store and they had a rebuilt one for my 1980 300sd for 50 bucks. If you cant find a rebuilt cheap, check junk yards. Boosters dont fail often.

You'll find it's easy to suck the brake fluid out of the booster by using a turkey baster from the .99 Cents Store , then poke a clean rag down in and allow it to sop up the last little bit of brake fluid at the bottom , take your time doing this .

Be aware that one droplet of brake fluid on any painted surface will instantly ruin it before you can wipe it off so work carefully ! .

Rather thn bench bleeding the master cylinder , I prefer to use a pressure bleeder , it's cheap simple and easy , you'll have the tool to use again and still be less $ than paying a shop to do this simple job .

There's an O-Ring in the face of the M/C where it meets the booster , be SURE to use a new one ! .

You're supposed to change the brake fluid every two years regardless of milage but few do ~ once you have a pressure bleeder , this should change .

I typically bleed the system dry before taking off the old M/C to ensure I'm starting over with only fresh fluid throughout .

DO NOT use more than 3 # when pressure bleeding ! .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better