66 master cylinder upgrade
 

I've been hearing rumor that the master cylinder off of a '67 with drums all around will change over to a 65 or 66 single resevoir model, is there any truth to this? I'm not ready to change the front brakes over to disks. Do I need to install a proportioning valve also?

I recently did this swap on my '65. Everyone told me I would need a proportioning valve but I did not put one in and it works fine. Take a look at my web site and download the article from the link right below the picture of the master cylinders. And remember to use the larger (rear) reservoir for the front brakes.

-JON

My understanding is that a proportioning valve is necessary only whe you have front disks and rear drums. This allpws you to adjust line pressure biased towards the the front disks. That keeps the rears from locking up on a hard stop. With all drums or all disks, I don't think you should need one.

Rev

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'66 Coupe, 306, 300 HP, C-4, 13.97 e.t., 100.1 mph
1/4 mi.

I'll agree with Rev on this one. The reason for needing a proportioning valve is the large difference in fluid needed to move the pistons. Disc brakes require a lot more fluid movement to move the caliper piston(s). The smaller brake cylinders on drums actuate with a lot less fluid. So when you have a disc/drum setup, you need the proportioning valve. http://www.mustangworks.com/interact...oard/smile.gif

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66 GT Fastback 5.0, 5-speed, cable clutch, JBA's, 3.40 gears, EFI coming soon?