Anyone got a C-series master cylinder to hand to take a measurement?

[jonny]

Made a schoolboy error... I needed to measure the thread of the outlet port of my C3B's master cylinder while I had my brake system stripped down, for a future project of adding a remote servo.

 

I remembered this, somewhat inconveniently, just after filling the system with fluid and spending an hour thoroughly bleeding the brakes... ???

 

Does anyone happen to have a C-series master cylinder on the bench, and if so would you mind measuring the outlet port thread? (The thread cut into the steel of the master cylinder itself, where the arrow is pointing in the photo).

 

Hoping I can avoid draining the system down again to take that measurement! ?

 

[MartinsB3B]

If I remember correctly either a 5/16" or 3/8" brake line screws into it. Standard thread.

[jonny]

Oops, I probably wasn't clear enough about the thread I mean.

 

On my truck there's an adapter whose male thread (tapered as I recall) screws into the master cylinder, and the female thread accepts the brake line fitting - a 5/16" pipe and 1/2" 20tpi fitting.

 

It's the male thread of that adapter which I need to know; my eventual aim is to convert the outlet to the 3/16" line which is what the remote servo units will accept.

 

 

Edited October 10, 2018 by jonny

[DJ194950]

Every Mopar old type master cylinder I have seen used a pipe threaded adapter fitting into the cast body. It should be either 1/8" npt or 3/8" npt male end by Inverted flare female to fit the brake line.

I do not have a C series truck but these old vehicles within the same manufacturers of the same era tend to be very similar on the mechanical  design.

 

If you can use some calipers and get  the outside dimensions of the fittings you have now and post I believe I or another can measure fittings they have and get the right info for you.

I have a box of pipe to inverted flare fitting to measure and maybe that way I could lead you to an answer.  ?

 

DJ

[59bisquik]

Johnny,

   Sorry for the late reply... but with the master cylinder off, why not do a Corvette dual master cylinder unit? The plate is simple to make and those masters are fairly cheap.