Stumped on this brake issue

67coupestang

Founding Member
May 31, 2002
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Heres the setup. 67 coupe, Front discs from a 73, Master cylinder from a late 90's Explorer, Willwood 4 piston rear disc

Just did the rear discs and afterwards it felt like maybe I hadn't bleed it thoroughly enough (was using a vacuum bleeder), But then I noticed it looked like one of the rubber lines in the front had a small leak, so I decided to replace them with braided stainless to match the rear. Now no matter how much I bleed it the pedal almost hits the floor, Brakes are there and if i pump it real fast its better. Once I can get some pressure it seems to hold, so i dont think theres a leak, obviously haven't driven it enough to notice any fluid loss. Did my MC just decide to crap out on me? And if that's the case any recommedations for a new one?
 
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67coupestang

Founding Member
May 31, 2002
508
2
19
well i went ahead and replaced the master, with a larger one no less 1.25 bore vs 1.0625. Bled and bled and bled, (made a pressure bleeder)

and while its much better still seems to be a fair amount of travel in the pedal.... I dont understand what braided lines would have this affect....
 

7991LXnSHO

wanna catch the space herp
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Sep 1, 2010
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Kearney, NE
well i went ahead and replaced the master, with a larger one no less 1.25 bore vs 1.0625. Bled and bled and bled, (made a pressure bleeder)

and while its much better still seems to be a fair amount of travel in the pedal.... I dont understand what braided lines would have this affect....
Braided lines should have less expansion than the rubber lines, and make for firmer brakes.
How much free play or travel before the rod presses the piston in the MC is there? Is the pedal for a manual or power set up, and are you using manual or power brakes? The pedal ratio is not the same.
 

67coupestang

Founding Member
May 31, 2002
508
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the pedal does sit a bit low at rest, I mean i can pull up on it about an inch. but as soon as the pedal is pressed it engages and moves the piston. I do have an adjustable pushrod coming...

The brakes are and have always been manual

Another piece to the puzzle, and Im not %100 sure I didnt imagine it but I happen to park it up hill the other night and in the morning the first couple times I hit the pedal it felt firmer. The mc I'm using has a port at the front on top for a switch, I thought maybe the plug I used didnt seal and maybe let some air escape? But when the pedal was released pulled air back in? but since then I jacked the front of the car up let it set for a few days, pulled that plug and wrapped it with some teflon and it didnt make any difference.