are the explorer, f-150, and crown vic parking brakes internal to the rotor ?

Ah, my misunderstanding. No sure why you decided to throw that tangent into the conversation though.

On a related note, the Dr Diff 10.75" rear disc setup ... which allows the factory and most preferred tapered axle bearings (and using whatever Mustang calipers)... does NOT allow clearance of the factory sway bar end links... therefore... you have to change the sway bar to an under-axle-design. That was a big surprise... I discovered it the hard way.. Cass confirmed (I wish it was indicated in his description of the setup). I had to remove my custom 1" factory-shaped upper sway bar... purchased a Helwig 7/8" (three point adjustable) under axle sway bar... a bit of a hassle to install ... but satisfying when all done (plus the purchase price.. fortunately, Summit had it in-stock and I recvd it in a cpl days).

Using the Cordoba 11.75" front rotors and factory calipers, along with the Dr Diff 10.75" rear discs, I cannot lockup the rears... only the fronts under severe braking... so far, relatively satisfied. I installed an adjustable proportioning valve... I leave it completely open... no bias needed towards front or rear... I could've probably not even bothered with that install.

Forgot to mention I have a proportioning valve to the rear brakes but I have never adjusted it, it’s wide open also. Pad material has had the greatest effect for me

what size master cylinder bore does the stock mustang use ? [what year application ?]

I dunno offhand, got rid of all my Mustang stuff years ago, but I do know the Cobra's, which is the source of the calipers, uses hydroboost.

97 SVT Cobra Mustang shows a 1” master cylinder with hydroboost

Well, crap.......That system would produce a LOT more fluid pressure at the calipers.

This is interesting. I somehow missed this when you first posted it.
A former Moparts member that is on FABO and FBBO mentioned that these Ford calipers have some weird quirks. Like what Sniper wrote, the parking brake ties into the caliper performance. I've read that the parking brake needs to be pressed and released several times to take up slack that forms as the pads wear. Failing to do so results in greater pedal travel before the brakes engage.

In addition to all of this, since 2001 I've used this '75 Dart single diaphragm brake booster:

Some people have said that the single diaphragm booster is likely inadequate for a 4 wheel disc system in such a heavy car. I'm just shy of 4000 lbs.
The factory dual diaphragm booster has been suggested.

I had this same concern when I swapped my front brakes to a configuration I made with viper calipers and a 14" rotor. I run the mustang cobra rear discs. After some initial driving, the pedal felt great, but I thought I would have been able to lock them up on demand. After many continuous hard stops, I could feel them grabbing harder once I got some heat in the pads. I run a standard parts store pad, but I'm sure a more performance oriented compound would change braking performance greatly. Try doing repeated hard stops from around 50MPH. I bet they start grabbing more. Just like Mitch, I installed an adjustable prop valve for the rears and its wide open. There's no need for one. FWIW, locking brakes doesn't decrease your stopping distance.

I know that. MY point was that if I'm not able to lock the brakes, I don't know if they are working to their full potential. If I could lock them, I'd know where that point of lock up is and brake up to just below that point.
Think of it like a throttle cable that isn't adjusted to allow full carburetor throttle blade opening. You could be driving around with a maximum of 3/4 throttle and not making the most power available.

I’m working with Mustang Cobra brakes on a Factory Five Cobra. I replaced the front pads (Hawk) because they would dust the rims with very little use. I went to Akebono ceramic low dust, and the pedal effort is much harder. I have tried to lock them up but so far unable…I need to try again. But iam running very sticky track tires. I might buy a new set of pads and hope they improve.

Pad material seems to have a big effect. My Just Suspensions front brake kit shipped with some dusty pads that were borderline scary when cold, and I don’t recall being able to lock em up. Carbon metallic pads installed last summer, less dust, ok when cold, and they do lock up

I dunno, my 96 Mustang had no issues locking up it's 4 wheel disc setup and it uses very similar calipers and such as the Cobra variety.

So it's not caliper or pad issues, it's lack of hydraulic pressure, imo.

A guy that was a respected member of this board, who is now posting at FBBO instead, said that the Mustang rear calipers need to be adjusted periodically. He said that sometimes the caliper pistons don't move out as the pads wear and that slack creates longer pedal travel.
Because of this, I pressed the parking brake pedal almost 20 times yesterday before going for a drive. The pedal travel was the best that it had ever been and I thought that I had stumbled upon the FIX for it all.
No, I did not.
Within a few miles, the pedal travel increased.....then the travel was long enough to trigger the warning light. The front reservoir was almost dry. The rearmost reservoir had about 1/2" of fluid in it.
I haven't checked the level in a few months but I found no leaks anywhere.
I went ahead and set up the Motive self bleeding tank and set to bleed the right rear corner first. I always slip some clear surgical tubing over the bleeder nipple with the other end into a bottle, all to contain the fluid and to minimize the mess. Clear fluid started coming through which was unexpected. I'm using DOT 5 fluid now. I guess when I bled the system last time, I didn't notice and didn't bleed it long enough to get all the DOT 3 out. Mixed fluids can result in a mushy pedal. I was getting inconsistent pedal feel for awhile. One time the pedal would have good feel, other times it might feel mushy. It was not confidence inspiring.
Out on the road, pedal feel is even and consistent now. The pads bite better once they warm up. I still can't get them to skid but they do slow the car down nicely. It is in no way dangerous, just not awesome. I may need to do some stops next to a modern car to see if they are comparable. If I'm on par with the Wife's car, I'll be impressed.

curious, cause your running a similar setup to me, but I couldnt see anywhere if your running a inline brake bias of some sort for the rear tires - do you have one in place?

By "brake bias" do you mean a proportioning valve?

If so, I do not.
In theory, 4 wheel disc systems should have all 4 calipers and rotors sized in a 2 to 1 ratio with the front having twice the braking force as the rear.
My front calipers have 2 pistons, the rear calipers have 1. The front rotors are 13", the rears are 11.7".


Some well intentioned people have suggested the use of a proportioning valve but I don't think that they fully grasp the issue here. A prop valve does not increase pressure, it only reduces it within the line in which it is installed. If I can't skid now, I won't be able to skid with even less pressure to the brakes.
My situation comes down to insufficient force at the calipers. The booster is either too small for the job or it has a leak, not allowing it to reach it's potential.

You keep mentioning booster or some other forms of assistance.

Can you lock them up manually? Maybe get your 6'8" neighbor to drive the car and stomp the pedal.

Assistance or not, if you press the pedal hard enough, it should lock up.

It isn't as if I am a 98 lb weakling. I'm over 200 lbs and in decent shape.
When I state that I can't lock up the brakes, I'm not bullshittin. They will not lock. They wouldn't lock with a manual master cylinder and don't with this A body booster.