Master Cylinder

[colinevans]

Hi
I have a 1971 280SL Coupe. The front calipers have been sticking for a while now, I think it is probably collapsed hoses but I want to give the brakes an overhaul. The master cylinder looks like its original and its very corroded on the outside, so I think it makes sense to change it at the same time. The problem is that Poole Mercedes have advised me that there were originally two types, Bendix & Teves, and they need to know which I have fitted. I can't see any markings on the cylinder or anything in the manuals. Can anyone please advise?
Many thanks
Colin

[Naj ✝︎]

Hi, Colin,

The calipers on your late car will most likely be ATE (Teves). Even if they are Bendix, they are interchangeable with ATE.

Replacement Delco ones are available on Ebay.

https://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItemVersion&item=332472805956&view=all&tid=1629742461014

This is the left one.

And the right:

https://www.ebay.co.uk/itm/MERCEDES-280SL-W113-2-7-Brake-Caliper-Front-Right-70-to-71-M130-983-Remy-Quality/332475969007?fits=Car+Make%3AMercedes-Benz%7CModel%3APagode%7CCars+Type%3A280+SL%7CPlat_Gen%3AW113%7CCars+Year%3A1970%7CVariant%3AW113+%5B1963-1971%5D+Convertible&hash=item4d691cadef:g:2ycAAOSw1NFaJ3h9


Note: They are handed left and right.

naj

[MikeSimon]

The cause for the sticking brakes is most likely the master cylinder. If the bleed holes are plugged, there is no pressure relief. Then again, old, corroded calipers may have stuck pistons.
I doubt it is a collapsed hose.

[colinevans]

Thanks Guys
Naj, it was the master cylinder make that I was talking about (that Poole Mercedes asked me to clarify), not the calipers.
Regards
Colin

[Cees Klumper]

My money is on the hoses.

[Jowe]

To second Cees, have a look at https://youtu.be/MHghO7DTses

[colinevans]

Thanks, hoses were my bet too. Do you think it would make sense to change the master cylinder at the same time, just because it’s probably on borrowed time? If so, any idea which of the two types it would be?
Regards
Colin

[Ulf]

Here's one - I've just ordered (a different) one for my 230 SL:

https://www.mbclassics.de/ATE-brake-master-cylinder-0024302801

Br

Ulf

[colinevans]

Thanks, think I might have to just take a chance on getting the right one!

[Ulf]

Otherwise try the SL Shop in the UK, this one should fit but ask them first :-)
https://www.theslshop.com/parts-shop/mercedes-benz-w113-sl-pagoda-parts/braking/mercedes-benz-sl-113-brake-master-cylinder-0034302201.html

Br

Ulf

[colinevans]

Many thanks Ulf, will do.

[Rick]

Hoses should be changed in the 12 year old and no more than 15 year old age range.  --   The insides collapse even with the outside looking perfect.

[Mike Hughes]

… and when they collapse internally they may allow fluid to move under pressure in one direction when pressing the brake pedal and then prevent fluid moving in the other direction when lifting off the pedal, effecxtively keeping pressure on the brake cylinder.