Projects 60 belair mc upgrade ?

I am wanting to upgrade my single bowl to a dual mc. What master cylinders ( 4 wheel drum, manual, 1 I ch bore) will fit ?

 

I cannot remember if there is any 4-bolt one that will fir. Later GM ones have 2-bolts, which line up with the bottom two bolts of your current master cylinder.

I think a 1969 Chevelle had a 1" bore, for 4-wheel drum.

 

Thanks

 

I used a 1967 Nova master in my 63 Bel Air.

 

So the 4 bolt pattern does matter?

 

If the big hole for the rod to p*** thru is in the middle of either top are bottom a two bolt mount is fine. I don't remember a four bolt mounted mc on Chevy.

 

1960 Bel Air, original:


Luckily, the back is the same, less the top two holes, as later GM stuff:

Just about any non-power GM ought to work.

 

I hope not. I don't suppose they would have done that rashly, and I think we would have noticed by now, since they made the switch over in 1962.

 

Ok cool, thanks. This is my weekend project.

 

Maybe.

One thing you will need to verify is the residual valve situation.

Your stock master cylinder has a residual pressure valve built into it. It keeps some fluid pressure in the lines, to keep the wheel cylinders preloaded, so they do not develop leaks.

You will need to verify that the master cylinder of choice has them in it.

A quick way to check is to undo the lines and look where they go. The is a cone in in each port where the flare seats. If those cones are made of the same Iron (or whatever the master cylinder body is made of), it does not have residual valves.

If those cones are br***, sometimes with a hex head, it might have residual valves.

Shown with one removed, in hand:

The reason I say might is that some master cylinders have br*** cones where the flares seat, and no residual valves, some have the residual valves removed, and others are repaired using br*** cones during the rebuild process with them.

You can verify, if you have br*** cones, with a paperclip. Straighten it out, and gently press it in the hole in the center. If you feel a little rubbery resistance just past the br***, it has a residual valve. If not, it does not.

This little duck billed dealy is the residual valve:



It, if it is there, is inside the br*** cone.

If there is no evidence of residual valves, you will need to add them. 10psi is the norm for drum brakes, and numerous companies make them.

 

Oh, and DO NOT remove the br*** cones to find out. Use the paperclip method!

Check, don't guess. Your life might depend on it.

 

Thanks