Ok, I have this master cylinder -= cast # 3461187

On the brass bail wire tag is
1176
and below that is 3659B
the there is PWR stamped on the outer edge

Is the 1176 a date of 176th day of 1971 ?
and the 3659B a vender code maybe

It's off a 1971 charger that was power brakes if it matters

1176 is the last 4 numbers of the Chrysler part number; 3461176
The other number is some sort of vendor number.
Those tags didn't appear until appearing on some new design master cylinders in 1971.
The only one I have here currently has the date code stamped in the nose of the casting.
To confuse matters, on disc brake master cylinders from '67-'69, they used a similar tag but it showed only the date code.
I don't believe any 1970's came with any sort of tags, their datecodes were stamped in the fender side of the casting.
This concludes disc brake Mopar master cylinder date coding 101, your diploma is in the mail.

Odd - I have three 187 master cylinders and all three of them are slightly different from a casting stand point.

I'll check date codes tonight now that I know where they are ... THANKS

I've seen 3461187 master cylinders with different casting numbers. The main difference I have noticed is the outlet bosses protrude different lengths.

I've got the part number casted into the part and casted out of the part (raised numbers) there are also some other features

Brad, I've got a 3461187 m/c with a brass tag on the bail wire with 0111 as first #, thought this was a date code too, following your info that it was the last set of #'s of a part #, I looked in my parts book and don't see these as the last #'s on any listed - any idea - guess it could have migrated there over the years too from another master using the same bail wire on a rebuild...thanks, Joe

That's interesting, I never have seen a tag like that.
The latest date code tag I have seen is from spring of 1969. I have an NOS disc brake master cylinder with a July '69 datecode stamped in the side.
Take a close look at your casting, see if you can find any datecode stamped in it, either on the fender side or the nose of the casting would be the place to look.

Nothing on the side Brad, on the nose is a 4 then space, then 51 - in the space I thought there was a faint 2 - but I think it's a space and just the casting of the metal/shadowing - what would the 4 51 spell out as - thanks - Joe

I don't see anything on the nose or the side of the casting of the one I have

casting #

tag in question

What was the correct finish for the bail wire and the top cover for this master?? Im thinking the cyl itself was natural (it was on my orig 26k mile Charger R/T) but the B-Body usually used the midland ross booster that was plated, not painted like the bendix booster on a 71 Challenger. If you have a 71 Challenger with a painted (bendix)booster was the master cyl painted together as an assembely like a 70 e-body ??? Yes I already know a 70 car had a different master.

Here is a picture of an NOS one I have, you can see it is all gray phosphate.
The bale wire looks like it has the same coating.

Date code

Of course on the '71 Challenger I bought last year, someone had painted the master cylinder black.
They probably used the same can of paint to paint the heater blower motor.
A couple more of the many details I need to attend to on this car. Anyone have any recommendations for a rattle can product that is close to the gray phospate coating?
And how about one that is close to the proper silver cad plating for my blower motor?

I used Seymour brand stainless steel paint for blower motor, master cylinder cap & bail