Have you tried isolating it to the front or rear lines with a plug in the M/C? See if you get a good high pedal on one end.
Did you bleed the master after replacing the line if it ran dry?

Last edited by 50vert (10/16/2018 9:38 PM)

Just realized I didn’t answer your question. I have manual four wheel discs on the 65 green coupe and have a high, hard pedal. It took forever to get a firm pedal. I had to build a pressure bleeding rig to purge all the air out of the system. I tried gravity bleeding, nope. Then putting the Mity-Vac on each wheel, nope. Then having the wife push the brake pedal while I opened and closed the bleed valve at each wheel, nope. Hooked up the pressure bleeder, purged the lines to all four wheels, got bubbles on all four. Then it had a firm pedal.

6sally6 wrote:

Never had a "nice-full" pedal on my Mustang....even after I switched to front discs and dual bowl.(in fact...I THINK the old jelly jar MC had a better pedal!...Can't remember, I've slept since then)
I have manual front discs and drum rears. I have tried to tighten down on the drums(as per MS suggestion) still...not much joy.
Recently I replaced the line from MC to rear brakes. New drums/shoes were installed this summer. (No leaky wheel cylinders)
MC is prolly 4 years old( it was a NEW/not rebuilt MC for a Maverick--front disc/rear drum) as are the front brakes.
NOW......after bleeding & bleeding &  bleeding the pedal goes 3/4's of the way to the floor. It stops.....butt looooow pedal.
I noticed today.......when holding pressure on pedal....I can feel it sloooowly go down almost to the floor!  IF I pump it a couple times I get a little more pedal butt I still get the slooooow travel toward the floor!
I think I know the answer butt.......sounds like the MC has crapped-the-bed......right?!
Anybody else with MANUAL front discez have the loooooow pedal like me  OR has the MC been 1/2 bad from the beginning ?
6sally6
PS........I love brake postz

I have the Maverick MC with 4 wheel disks.  The pedal goes down a ways, but not too far.  I can lock up all four. 

The pedal seems a little soft, but I cannot be sure as I drive my '15 GT most of the time and its brakes come on right now fairly hard.  There is a big change in feel and I am not sure whether there is air in the system or just too big of a difference.  I'm not pushing hard enough.

If there are no leaks, I think the problem lies with the MC.


 

Last edited by lowercasesteve (10/16/2018 10:47 PM)

Some of it's going to depend on the size of the piston in the master cylinder. I think the maverick is a 15/16" piston. I'm using a master of a early 70's Mustang with a 1" piston. I also have braided stainless steel hoses in front.I have a real firm pedal that doesn't travel too far. I wouldn't worry on the stroke length as long as the brakes work well. The 15/16 piston will require a longer stroke but less pedal effort.. I do think you have a leak somewhere, probably internal to the master.

I do want to note the early 70's Mustang disc/drum master I used, I did not realize it at the time but it does not have a residual check valve internally nor did I add a external one. I'm not recommending this just commenting on my set up

Steve, it is a valve I got from you years ago. I recall you saying that's why you stopped selling them.
I'm replacing it to go with a more correct part.