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Discussion Starter #1
i just cannot get rear brakes, this is a 66 it came with power drum brakes but did not have the factory booster and master when i bought it. the po had someone install a booster with a geo metro master cyl, i removed that fubared mess.
so here is what i have done, switched it over to front disc brakes from Dan at chockostang < he and his wife are just wonderful people!
installed a 74 maverick manual disc master, a ford disc brake porp valve and a 10 psi residual valve, installed the dual exhaust rear line and hose, axle lines, raybestos pg shoes, new combi kit, wheel cylinders,parking brake cables. bled a qt of brake fluid through it both with a vacuum bleeder and had the wife help with the good ole manual pump and bleed.
so when manual bleeding i get plenty of fluid, i jacked it up and ran the car in drive and i have to push the pedal to what is the point that while driving it around the fronts lock up and it will stop the wheels but not an instant stop just gradual. the pig should have fantastic brakes...but she don't!
i have to be over looking something i mean this aint my first rodeo.
help me out fellers
Jeff
 

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If the MC or distribution block had a limiter fitting of sorts, or if you're using an adjustable proportioning valve somewhere, you may not also need the residual valve. Check with Chock directly.
 

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I have pretty much the same m/c with adjustable proportioning valve, Kelsey hayes front discs with 10" drums. I was told specifically to not use a residual valve. Works like a champ.
 

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I would try without the the residual valve also. My ‘66 GT has no residual valve and it stops fine with the OEM MC and the dual bowl MC.

you also need to adjust the rear shoes per the shop manual. There should be a decent amount of drag.
 

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Have you adjusted the rear brakes yet? I had this same issue when I did the 4 piston disc front brake swap. Talked to chock about it and he suggested adjusting the rear brakes so the drums have a good bit of resistance when turning. I tried this and it actually made a huge difference.

My rear drums were not as tight when I was running the 4 wheel drums and both front and rear worked fine. After the swap I found I needed the rears to be quite a bit tighter before I could get them to lock up at all. From there, fine tune the prop valve to get the proper bias between front and rear. You want the fronts to lock a split second before the rears.
 

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Discussion Starter #7
there is no adjustable porp valve on the car, i have adjusted the brakes to where there is a good drag.
 

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cheapie brake pads will have crappy stopping power. You can upgrade to better pads. Or at least check for glazing and maybe hit the rotors and pads w/ some sand paper and then re-adjust and re-do the bedding of the brakes?
 
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Yup. Where did you get the front pads?

ex-Global West GM
1991-1995
 

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It looks like his distribution block is the 70 style. It had the proportioning valve built in. It used to be the choice for brake swaps, but as it was used on heavier cars than the earlier models, people started using the adjustable valve instead.
 

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I can't really tell from your photos but may want to double check the routing. Looks like you are coming out of the master to the residal valve then looping back from the exit of the residual valve into the top of the por[ortioning valve but I cannot see everything, it looks like a pretty tight loop back if so. Are you sure you have the residal valve in correctly? If it was in backwards, that could explain things. Could be a bad master...
 

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If I am not mistaken the residual check valve is built into the master cylinder you are using. Just plumb the master straight to the proportional valve, just as was done on the Maverick.
 

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I can't really tell from your photos but may want to double check the routing. Looks like you are coming out of the master to the residal valve then looping back from the exit of the residual valve into the top of the por[ortioning valve but I cannot see everything, it looks like a pretty tight loop back if so. Are you sure you have the residal valve in correctly? If it was in backwards, that could explain things. Could be a bad master...
I think you are right about the residual valve, it doesn't appear to be going to the rear brakes.
 

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Discussion Starter #15
front pads are raybestos and i just machined the rotors, problem is with the rear brakes the fronts work great and are seated properly. it can be hard to make out but the lines are plumed correctly. i talked to Chocko Dan and he gave me some great advise to work with so out in the shop i go tomorrow.
Thanks fellers for the replies its what makes this a great site.
Jeff
 

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A couple comments...

1. Re-adjust the rear brakes. Crank that "star wheel" until you can't turn the rear wheel and tire by hand, then back it off until you get desired drag. Sometimes the shoes don't "set" correctly at the anchor or wheel cylinders.

2. If your Raybestos front pads are "ceramic", send them back and get some semi-metallics.

3. Check your pedal pushrod for length. One that is too short, as well as one that is too LONG, will affect brake performance. A pushrod that is too long won't allow the M/C piston to return to its "resting" position, uncovering the equalization ports.

4. If brake performance STILL sucks, see if your parts stores "loan-a-tool" program has a brake pressure test kit so you can check pressure at various points in the system. Start with the farthest-away point.
 

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A couple comments...

1. Re-adjust the rear brakes. Crank that "star wheel" until you can't turn the rear wheel and tire by hand, then back it off until you get desired drag. Sometimes the shoes don't "set" correctly at the anchor or wheel cylinders.

2. If your Raybestos front pads are "ceramic", send them back and get some semi-metallics.

3. Check your pedal pushrod for length. One that is too short, as well as one that is too LONG, will affect brake performance. A pushrod that is too long won't allow the M/C piston to return to its "resting" position, uncovering the equalization ports.

4. If brake performance STILL sucks, see if your parts stores "loan-a-tool" program has a brake pressure test kit so you can check pressure at various points in the system. Start with the farthest-away point.
Great info here as always.
If the piston in the master does not fully return, it will cause issues. In this case I think it is fully returning because the fronts work fine, and do not continue to brake when pedal has returned. If the return port was covered (to long a push rod) the fluid could not return keeping pressure in front brakes, thus drag.
I believe Whitey is going to try the rear brakes without the residual, and the new proportioning valve. Plumb it up direct. If he has adequate braking then, the fault has to be in one of those valve. If no difference, as woodchuck eluded to, there nearly has to be something wrong in the rear drums, the cylinders, wrong shoes, etc.
Yes, not ruling out the master, but it produces a big squirt out each bleeder when bleeding by the 2 man system. So ???, stay tuned in for the next episode of the braking mystery.
Whitey is a ole boy who still enjoys his Mustang.
 

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front pads are raybestos and i just machined the rotors, problem is with the rear brakes the fronts work .......”.
once you get the rear brake issue solved, and there’s some great pointers in this topic, think about changing those front pads.

Yes, the Raybestos pads will give you adequate braking. But upgrading to either the ebc redstuff or the Porterfield R-4s pads will move the braking quality from “OK” to superb.
I prefer the ebc, but the Porterfield’s have a good reputation as well.

Z
 
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