Author Topic: Early 1967 250SL - Master Cylinder Replacement Questions  (Read 676 times)

NoEcm

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Master Cylinder appears to be frozen and leaking:






Early chassis (below #02980) so it appears that I'll need the more expensive Master Cylinder p/n  001-430-89-01


Questions:

1. Does a new master cylinder include the grommets for the fluid reservoir?

2. Does a new master cylinder include the O-Ring that fits between the master cylinder and brake booster?

3. How difficult is it to move the brake fluid reservoir between the old master cylinder and the new one?

4. When I just barely touched the little rubber plug on the brake fluid reservoir nipple it fell apart, any suggestions on how to make or secure a replacement?

5. Any other tips or suggestions?

Thanks!
1967 250SL
Automatic
VIN: 11304312001340

Jonny B

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #1 on: July 04, 2019, 15:03:33 »
Authentic classics has the reservoir and their part includes the little black rubber piece - reuse the clamp you have on yours.
Buds Benz has the picture (and it includes the black rubber piece) but their's is listed as NLA
Jonny B
1967 250 SL Auto, DB 568
1970 280 SL Auto, DB 904

Pawel66

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #2 on: July 04, 2019, 16:09:40 »
I am not 100% sure, but this plug, I think A 000 987 03 45 (?), may be available at MB (it is here in Europe, if it is this part - you do not see it in the picture in the EPC, but it is there together with the clamp on the parts list, it may be this one you ask about). It is $ 3-4 here.

Keep the original small clamp, I think it is quite rare.

I am not sure if the fluid reservoir you have is available in its exact original shape. I would keep it (I think this is what you are planning to do). It has been discussed in another post that a good wash with soap water or washing powder may significantly improve its look (yours does not look that bad, actually).

The sealing ring between the master and booster is available in MB, ca $5 (A 004 997 32 45).

I do not know if master cylinder kits include the reservoir grommets.

What I see is that the grommet appears as a separate spare part "As of ident. no.: 043 002980" and it has a part number A 000 431 09 35. This chassis number marks also the change of master cylinder types or PN. Could be the earlier one had grommets built in the later one - separate - but I am not sure, you would need to confirm.

There are also some repair kits in MB, but do not know if applicable in your case.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

NoEcm

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #3 on: July 24, 2019, 06:28:15 »
I found a temporary solution to that little black plug on the master cylinder reservoir:

"Dorman Help! 47396 Vacuum Cap". I paid less than $4.00 for the assortment of 8. Perfect fit and I was able to use the original clamp.




Keep in mind that this is only a temporary solution as I do not know how compatible this rubber is with brake fluid.
1967 250SL
Automatic
VIN: 11304312001340

mauro12

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #4 on: October 17, 2020, 17:55:52 »
I have a 250sl early chassis too and I’m starting to think that would be a great idea to buy the new master cylinder and save it. I read somewhere that this pieces will be not longer available shortly or maybe the price will be near 400/500 dollars. What do you think could be the best way to prevent brake fluid failure? Try to use more often the car and so the brakes?
Mauro Pisani
250sl 1967 5speed zf manual

NoEcm

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #5 on: October 17, 2020, 20:01:20 »
I have no opinion of buying a master cylinder and saving it for future use. $500 is a lot of money and there are other places I can spend that now. By not buying one and setting it aside for future use I hope I don't kick myself down the road.

But as an FYI the leak that I had was from between the reservoir and the master cylinder. Simple and cheap fix (under $25). Google "ATE 390001" and you'll find the repair/reseal kit.
1967 250SL
Automatic
VIN: 11304312001340

thelews

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #6 on: October 17, 2020, 20:16:13 »
If you drive your car and bleed your brakes regularly to remove moisture, your MC should last just fine.  Worn seals can be replaced.  I would also think there are generic solutions that would not look original.
Enjoy some pictures at this link:
http://www.flickr.com/photos/8292359@N06/sets/72157603240571101/show/

John - Wisconsin
1967 Early 250 SL Red/Caviar, Manual #1543
1961 190 SL 23K miles
1964 Porsche 356
1970 Porsche 911E
1991 BMW 318is
1966 Jaguar XKE

inci

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Re: Early 1967 250SL - Master Cylinder Replacement Questions
« Reply #7 on: October 18, 2020, 03:02:31 »
take a look at rockauto.  remanufactured/tested. $45
CARDONE 111919
John Inci
Development Engineer
Mercedes-Benz US Int.

W113 '67 250SL Blue - Restored!
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