Anyone proficent with 1967 Mustang power disc brakes?

[67428GT500]

I am running the factory disc/drums on my Shelby. It's a factory cylinder dimensionally. 1"

[Falcon67]

You'll pick up line pressure going to 15/16 or 7/8 bore if available.  IIRC Ford MCs use the same bolt-to-firewall mounts from 60s through the 80s or 90s.  Why some people run Ranger pickup aluminum units. 

[falcongeorge]

When I converted my '67 Cougar from manual four wheel drums to manual front discs, I consciously went with a 68 setup.  I wanted the simpler and cheaper single piston setup.  I got a factory front disc setup off of a '68 Cougar and put it on. 

I used a Ford Maverick manual front disc master cylinder.  For me, it works perfectly.

paulie

I have a '65 falcon in my backlog of someday projects, it has the KH 4 piston calipers. Everything I have read says the fixed four piston calipers are superior in performance to the later single piston calipers, I haven't actually driven that car yet (god willing, I will get it finished before I shuffle off this mortal coil ) so I don't have any first hand empirical evidence, but that's what I have heard, from multiple sources.
FWIW, I am putting 2005-up 12.5/11.75 Mustang discs and bullit wheels on my '67 falcon driver.

[67xr7cat]

You'll pick up line pressure going to 15/16 or 7/8 bore if available.  IIRC Ford MCs use the same bolt-to-firewall mounts from 60s through the 80s or 90s.  Why some people run Ranger pickup aluminum units.

Whole point of the 1" bore mc and revised pedal leverage point on the power assisted brakes is to reduce the pedal travel. If the power booster is working correctly should generate plenty of pressure.

[Falcon67]

Sorry, I should have clarified that those bores are good for manual brake.  Power assist is way different - different bore and different pedal leverage as you stated.  My bad - I don't use power brakes on anything except the daily driver types. 

[67xr7cat]

Don't blame you, properly set up manual disc work well. Less stuff in the way and no cam low vacuum issues. Only reason for post was to keep discussion in context of what op has so as not to confuse the issue.

[67428GT500]

Well, yes. They will bolt to the firewall. However, there are differences with power brakes. The Midland-Ross Booster isn't so forgiving. I don't mind brake size changes. As for the 4 piston calipers: All race oriented brakes are fixed multiple piston calipers that I have seen in use for vintage Fords.
                                                                                                                      -Keith

[e philpott]

Smaller bore will make more pressure. The 57 Chevy Junkyard Dawg on the Jegs cover we had to reduce MC bore to make it easier to stop with a handicapped driver and 3900 pound package , I agree with the  scrap the power brakes too , the few people that drove my Fairlane didn’t realize it didn’t have power brakes until I reminded them

[67428GT500]

I'm not scrapping power brakes on a real Shelby. It's out of the question.  I do have larger than factory rear drums. 11X2.5. I don't think it factors into the problem being the cylinder is the same size as the original 10X2.5 that came on it. I thought perhaps someone had ran into an oddball situation.

                                                                                              -Keith

[Falcon67]

Agree with the not modify on a Shelby.  Your parts should work as installed.  Especially with the larger rear drums, those should self-engage and work well with the front disks.  It's not uncommon these days to have a new MC be faulty in some way - passing fluid internally and such.  Or for some reason there is insufficient vacuum assist - may be plenty in the intake but not making it to the booster diaphragm.

[C8OZ]

... Or for some reason there is insufficient vacuum assist - may be plenty in the intake but not making it to the booster diaphragm.

I had a leak between the vacuum fitting/check valve at the booster that would only show up when you flexed the hose slightly. It would build plenty of vacuum stationary at idle but lose enough driving to be a problem. Hose twist and reroute to a friendlier angle was the whole fix.

[gdaddy01]

make sure you bleed both sides of the front calibers , I had the same problem , it is easy to over look the inside bleeder , may have all ready been mentioned

[67428GT500]

I am not sure what you mean by both sides of the calipers. The KH four piston calipers only have one bleeder and the cross over line to the other side of the caliper. As with any complete bleed I start with the furthest away wheel. Right rear and the left front side is last. I use the distribution valve centering tool as well. There was no air showing up in the tubing post bleeding. I have the engine out currently and have purchased a new Master cylinder.  I am also going to change the two front brake hoses as I don't like they way they are crimped. Perhaps there is some restriction because of the crimps.  I have never had a system issue post any rebuild. Once in a while we can't see the trees for the forest so I thought I'd throw the question out to see if something popped up I negated to consider.
                                                                                                                 -Keith

[gdaddy01]

it has been awhile sense I have bled the brakes , I thought there was a bleeder on both side , I guess not , but I had air trapped in the caliber , maybe I just broke the line crossing over ,  but I had what sounds like the same problem you are having . after I got the air out I had good brakes . sorry if I made it worse . 

[Falcon67]

Brakes are designed to give us fits.     The dragster has two calipers, bleeders on both sides of the calipers, one steel line with a T, one small manual 7/8 bore and a pedal.  It's "musical caliber bleeders" just to get a good stiff pedal on that car.  The MC holds about half a coffee cup but when it's time to start running fresh fluid I buy a quart jug.