Question on master cylinder

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DavidLee

DavidLee

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i am doing the conversion from the older cast steel mc to the newer aluminum mc. I am going to use braided line from the mc to a 4 port willwood valve. What is the size of the ports on the newer mc.
 
Depends on the MC you use. You might be referring to the 80's Dodge truck one, which I think is the basis for Dr Diff's. I used a 97 Breeze ABS MC. Both ports are the same size - 3/16" tubing w/ inverted flare and I recall the smallest tube nuts for that size tube. 1970's Dodge cars used different size tube nuts for F & R ports so you couldn't mix them up, but they might have dropped that by 1980's. Be careful of MC's later than ~2000 since many changed to "bubble flare" ports, w/ metric tubing (6 mm, I recall, though is actually close enough to 3/16" to interchange).
 
this is the MC, I am going to use

_CCM2078.jpg
 
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I must ask, why not a new one? Unless you know the history of it or plan on rebuilding (kits are usually more than a reman unit) i wouldnt trust it.
 
I don't know what the silver fitting in the fwd port (for rear brakes) is. Some MC's had a "residual valve" in a port for the drum brakes, but I don't think it sticks out and is visible, and wasn't used by the 1980's. Your ports look like the smallest tube nut size for 3/16" tubing. The threads are standard SAE, so try screwing different bolts until you find the thread size, then compare to tube nuts, or take it into Ace Hardware and use their "thread finder" tool. I recall many sellers on ebay list the thread sizes. You will need a "double-flare" tool to make the tubing, and don't skimp on a cheap one or you will get frustrated. Many here like special tubing (Ni-Cu I recall) which is much easier to bend and flare.
 
BillGrissom said:
I don't know what the silver fitting in the fwd port (for rear brakes) is. Some MC's had a "residual valve" in a port for the drum brakes, but I don't think it sticks out and is visible, and wasn't used by the 1980's. Your ports look like the smallest tube nut size for 3/16" tubing. The threads are standard SAE, so try screwing different bolts until you find the thread size, then compare to tube nuts, or take it into Ace Hardware and use their "thread finder" tool. I recall many sellers on ebay list the thread sizes. You will need a "double-flare" tool to make the tubing, and don't skimp on a cheap one or you will get frustrated. Many here like special tubing (Ni-Cu I recall) which is much easier to bend and flare.
Click to expand...
i found out what sizes they were, and I am going to use braided line to the willwood prop valve
 
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