Brad Chapin

Time to redo a few things with the 72’s brake system. Ordered up a new master cylinder from Rock Auto that said it was dialed in for my vehicle but when I received it- this baby is significantly larger than that stock master cylinder. I have the room in the engine bay but I would love some experienced insurances from some people before I bench bleed this thing and install it. If I need to make a return I’d prefer to do so sooner or later.
So any thoughts on a larger master cylinder for a guy that knows nothing about the differences would be great!

Gpc1

It just has a different look and a bolted cap. Bleed it and install it should be perfectly fine.
Greg

joe_padavano

The aftermarket M/Cs with the bolt on cap always looked wrong to me. Functionally all that matters is that the bore is the same as original. The cap has no functional impact.

edzolz

Very important issue here. Bore must be the same for brakes to work properly.

Burd

Get the OG one rebuilt. Keep the numbers. I had mine done for $35

joe_padavano

Look again. The one he has does not have bleeder screws. It's already been replaced once.

rickw30

eagle eye

Schurkey

Visually wrong, and that would bother me. Functionally OK.

WHAT'S WRONG with the one already on the vehicle?

There are "rebuilt" master cylinders available at every parts store in America. You go there, you can see the item you'd be taking home.

For that matter, a rebuild kit, a brake cylinder hone, a can of brake cleaner, some brake fluid, and half-an-hour and the one you have now could be refreshed. This is from my beater truck, a couple days ago:

Of course, with an aluminum casting, there's no honing the bore. Leave it the hell alone. If there's a problem, you buy a rebuilt or new master cylinder.

Koda

Burd, I think not many people here know the term OG.