no pedal

[72 440 modart]

 ???working on a 73 duster and can't get a brake pedal. All new brake compnents.The car has manual disc brakes(converted from power)
I used the brake push rod from one of my other cars that had manual drum brakes.Is this the right rod to use?It measures just over 6
inches from the tip that goes into the master to the center of the bolt hole at the brake pedal end.The brake pedal almost goes to the floor before you get resistance.I've bled the brakes multiple times and no air comes out of the system.Is it possible that the valve in the distribution
block has moved to the far end and can't return to it's proper posiition.

[blown71duster]

One way to check your brake problem would be to put plugs right at the master cylinder where the lines go in , with those plugged assuming the master cylinder has no air and is in good working order [not bypassing] you should have a very firm pedal . If you don't then there is a problem with too short of linkages. If you do have a good pedal now then you have air in the system somewhere  from the master out. Hope this helps

[Ryan (Strange246)]

Did you "Bench bleed" the master cylinder?
Ryan

[72 440 modart]

Yes I did the strange thing is each coner of the vehicle bleeds properly but the pedal won't come up

[72 440 modart]

Just had a thought does it make a differance which side you mount the calipers on. Mine are towards the
rear of the vehicle with the bleeder screws on the top

[Jim_Lusk]

Bleeder screws must be to the top (don't ask me how I know, it was a long time ago). Are the three hoses new?

[qkcuda]

The bleeders need to be on top Mike, since the air will rise to the highest point.  I don't have any suggestions except what you have already tried.

[TireFryer]

Are the rear brakes properly adjusted?

[attachment deleted by admin]

[72 440 modart]

new calipers pads flex hoses(f&r) all new steel lines new spring kit on rear shoes etc etc etc as far as the rear shoe adjustment the drums
have a fair bit of resistance to slide them over the shoes.When you apply the brake pedal all the way to the floor you can't turn the drums
but you can still rotate the rotors.Hope this helps

[Jim_Lusk]

Check your bleeders............

[72 440 modart]

Hey Jim I assume you mean check for obstructions.If somebody sits in the car and pushes the pedal if I open the bleeder thr fluid
streams through the hose I've attached to it as if everything is fine

[Jim_Lusk]

NO, I mean, is the bleeder at the top or bottom of the caliper?

[Capt Jack]

isnt there a return spring on the brake pedal?  is that broken or missing?
also, is the proportioning valve adjusted properly?

[Lars]

No, there isn't a return spring on the brake pedal. Sounds a lot like the master is bypassing. I know you said all the componets were new, but what type is the master? A new aluminum master, or a remanned cast iron? I had a couple of "rebuilt" cast iron master flake out on me soon after install (one didn't even make it off the bench). Get someone to pump the pedal and check out the rubber line on the front to see if they are expanding or not. Also (this is kinda a dumb question) you do have the correct ports on the master hooker to the correct points on the prop valve right? Is this a disc conversion, or did it come with discs?

[72 440 modart]

hey Lars the car was already disc brakes. The car was completly disassembled for a ground up resto.I reused the master and prop valve that
was on the car prior to the resto. It all worked fine before. The items I did change are power to manual disc brakes and 11 inch rear brakes
and like I had mentioned earlier that I used the push rod from a manual brake drum car. I don't know what the length this rod should be.
And to answer your question Jim the bleeders are on the top.I'll double check where I've placed the lines into the distribution block.I'm
sure I did it as per the shop manual.

[Lars]

Sometimes the rod that contacts the MC are adjustable on some boosters. Maybe you aren't getting full engagement?

[72 440 modart]

Just finished double checking the lines going to the prop valve. Everything is in the correct location. In the shop manual it mentions
if you have a front brake failure that a valve in the prop valve moves into a bypass mode giving you brake pressure to the rear of the
vehicle.I mentioned in an earlier post that the rear drums do stop turning when the pedal is almost on the floor but the rotors still turn

[Lars]

Could be, are the calipers leaking?

[qkcuda]

That sounds like the problem Mike.  Does it tell you how to reset it?

[sportfury70]

Are the rear brakes adjusted properly?  That is where you get your "pedal"  Lewis

[72 440 modart]

Finally had a chance to check out a few of your suggestions. No luck. I took the brake distribution block off (real fun with the engine in)
took the block apart everything seems fine with it. The strange thing is when I undid the lines from the master to the distribution
(at the block) the rear portion of the master cylinder, all of the brake fluid had drained out. But the front portion of the master,which
is for the rear brakes still had fluid in it. Is it normal for fluid to pass through the master cylinder if the brake pedal has not been pushed?

[blown71duster]

whenever you have a low pedal going almost to the floor, It has to be because of 4 things I can think of. air trapped in system you can usually pump the brake pedal up though in that case. misadjusted brakes on rear , excessive to get a low pedal almost to the floor like you discribed? A leak, causing the pedal to drop maybe leaking at rear of master cylinder? No complaint of fluid loss though in this case. I would say you have a problem in the master itself probably bypassing internal .In our shop  if we would suspect this,the first thing would be to plug the master, right at the ports , with plastic plugs that come with new master cylinders to bleed , with those tight you will have NO movement in your pedal { there is nothing to move rear shoes, caliper pistons} That is the best test you can do to check a master cylinder out .  good luck,   Kevin

[72 440 modart]

Hey Kevin what is the way that you adjust the rear brakes. I've got it so that the rear drums are snug
to slide past the shoes. No visable fluid leaks.I'm leaning towards the master also.

[qkcuda]

Mike the rears don't seem to be the problem, since they are holding when you press the pedal.  I agree that it looks like the master is bad.  I would get a new one and try it before I pulled out any more hair.  It's not like you won't have another car to use it on if that turns out not to be the problem.