Did my 1969 Coronet come with the wrong master cylinder installed?

[OneWheelPeel]

The MC is leaking a bit so I'm trying to order the replacement, whats on the car now has the wire spring thing to hold the top on, but the ones I find for my car at Oreilly's. Autozone, RockAuto and Classic Industries all have a bolt on top.

My car is manual drums all around, if what I have is incorrect can anyone ID from the pics? My main concern is the new one won't bolt up or has the correct threads to seal the lines. Here is a pic of whats in my car as well as a representative of what I'm finding online.
Ignore the rest of my beautiful engine compartment

Also if anyone has a best bet on where to order from since parts are a crap shoot nowadays, please share.

 

[WileE]

If you have manual drums, the correct master cylinder has equal chamber volumes, with a clamp that holds the cover on with a bolt in the middle.

 

[WileE]

This is the type. Those aftermarket ones have those fugazy type covers,

 

[Sam69sat]

No idea the quality of these parts or if they'd fit but you might be able to rebuild it if you don't want to get a different one.

More Information for DORMAN TM59051

 

[68BabyBlue]

Installed on my former GTX with manual drums.

 

[OneWheelPeel]

Ok thanks everyone, looks like I have a mystery MC in the car but it does appear to have equal sized chambers front and rear. It stops really well whatever it is. I did just look at it more and it really seems like it is leaking from the lid, the sealing surface is kind of cruddy etc and there are rust particle stuck to the rubber.

 

[MWbirdLOVER70]

Ok thanks everyone, looks like I have a mystery MC in the car but it does appear to have equal sized chambers front and rear. It stops really well whatever it is. I did just look at it more and it really seems like it is leaking from the lid, the sealing surface is kind of cruddy etc and there are rust particle stuck to the rubber.

Had same problem last year and tried another rubber gasket but still leaked. New master and it went away. Crappy rusty wall tops

 

[Don Frelier]

DOT3 is devil's urine.
Oops sorry that's a different thread.

 

[YY1]

Different designs.

Should be interchangeable.

 

[gtx6970]

The bail wire style is 1971 and later drum brakes

 

[OneWheelPeel]

The bail wire style is 1971 and later drum brakes

Guess that car really went thru the wringer at some point and just had whatever parts put on.

 

[1 Wild R/T]

Guess that car really went thru the wringer at some point and just had whatever parts put on.

Not uncommon.. Do you want it correct? Or just want it to work? When guys depend on a car to get them where they need to go they rarely give a crap what the part looks like if it works...

 

[YY1]

...and yes, if left sitting DOT3 may/will eventually get the reservoir top edge.

 

[MWbirdLOVER70]

This time I flushed and used Dot 5

 

[OneWheelPeel]

Not uncommon.. Do you want it correct? Or just want it to work? When guys depend on a car to get them where they need to go they rarely give a crap what the part looks like if it works...

I've been that guy! I just want it to work safely. I won't do anything to the car that makes it terrible for the next guy if he wants it correct but that's as far as I go there when it comes to "correct" or restoration/stock.

...and yes, if left sitting DOT3 may/will eventually get the reservoir top edge.

Yesterday I cleaned up the top with a file and cleaned the seal, blasted it all with cleaner and it was not as messy this morning, but still a little wet/dark, usually its a mysterious mess just from sitting a day after I clean it up. So maybe this is the issue. It would be nice if I could find the gasket for what I have to see if that helps.

This time I flushed and used Dot 5

Is Dot 5 better when it comes to issues like this?

 

[MWbirdLOVER70]

I've been that guy! I just want it to work safely. I won't do anything to the car that makes it terrible for the next guy if he wants it correct but that's as far as I go there when it comes to "correct" or restoration/stock.

Yesterday I cleaned up the top with a file and cleaned the seal, blasted it all with cleaner and it was not as messy this morning, but still a little wet/dark, usually its a mysterious mess just from sitting a day after I clean it up. So maybe this is the issue. It would be nice if I could find the gasket for what I have to see if that helps.

Is Dot 5 better when it comes to issues like this?

That I can’t tell but I can tell it won’t eat your paint if you spill it on your aprons on the side of the master cylinder is on but remember all the Dot 3 must be removed from the system. Do a search and see what others say please

 

[68BabyBlue]

My current GTX was switched to Dot 5 when it was restored over 20 years ago, and there is still no sign of corrosion around the original master cylinder. Replaced a front disc brake caliper this year because of a leak, but no corrosion problems of any kind.

 

[YY1]

8 years on Dot 5 for me without issue.