Need some help with brake issue

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71DodgeDemon340

71DodgeDemon340

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Hey guys boy oh boy when it rains it pours lol. So i just got done installing new 11.75” rotors with 2.75” calipers and stainless brake hoses. I went to bleed the front brakes and before i did i suck out almost all of the old fluid from both chambers, left enough in the bottom to keep the ports covered. Filled with new dot 3 brake fluid and used a vacuum bleeder on the front and flushed about a quart of brake fluid through the front calipers. Was going to flush the rear after. But before i even started on the rear i went to go see how the pedal feels and there is some pedal feel but it doesnt get hard until maybe near the floor, i know it should be rock hard after about a inch or so depressing the pedal shouldnt it? I slid the wheels and tires on and had my dad hit the brakes and the fronts are definitely working but the pedal seems way too soft to me. Sitting in the seat i can about force it to the floor and pumping it doesnt seem to help. I then went to the back drums, i had to adjust them up slightly and then bled about a half a quart through the wheel cylinders and i now have clean fresh fluid throughout and no air that i can see coming out of the bleeders. But still the pedal doesnt get rock hard. You can feel some resistance but it doesnt change pumping it. Also not sure if it could be related but with the cap off the master when i push the brake pedal the front chamber (rear brake chamber) geysers, fluid squirts up maybe 2” above the reservoir and the rear chamber (front brake chamber) does not. Any thoughts?


Also on the last round of bleeding the drums the right rear bleeder broke off when i went to tighten it. Tried to get the remaining piece out with vise grips but no dice. So pulled the drums off and there was one droplet of brake fluid on the left rear wheel cylinder and maybe some light residue around the area but no major leak. Also the shoes have a few cracks in them so I guess im putting new wheel cylinders, shoes and hardware on now
 
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The front resovor and the rear are internally tied together by the pistons. Meaning fluid from one can effect the other. Maybe you got some air between the two pistons
 
If you switched the spindles left and right to move the caliper to rear, Double check caliper locations. Bleeder needs to be at top.
 
RedFish said:
If you switched the spindles left and right to move the caliper to rear, Double check caliper locations. Bleeder needs to be at top.
Click to expand...

they are, installed dr diffs 2.75 calipers which have bleeders at the top and bottom for either caliper orientation
 
after you swap the brake cylinders, (yes, do them both), bleed everything in the correct order. rears first, pass then driver side. then the fronts. pass then drivers side. vacuum bleeders are convenient, but having someone pump the peddle is much better. no reason the have the cap of the MC unless you want to remove paint from around it
 
kursplat said:
after you swap the brake cylinders, (yes, do them both), bleed everything in the correct order. rears first, pass then driver side. then the fronts. pass then drivers side. vacuum bleeders are convenient, but having someone pump the peddle is much better. no reason the have the cap of the MC unless you want to remove paint from around it
Click to expand...


I thought it was RR, LR, RF, LF?
 
If the pedal does NOT get hard with multiple pumpings;
in all likelihood the compensating port is not operating correctly;
or the master is bypassing fluid back into the reservoir,
or, as mentioned, you could have air stuck in the master somewhere.
There is also a slim chance that your new brakes have a mechanical issue.
As to diagnosis; I would
remove the calipers and C-clamp them into the bottom of the bores, then check the pedal. If still soft;
you will have to check that the C-ports are open and the pistons inside are returning to the park position,all the way towards the firewall.
After that, if still soft, I would "bench-bleed" the master, then pressure-test it.

My gut feeling is that the pistons in the M/C are not parking at the back, or the C-ports are restricted/closed. When this happens, the same brake fluid just shuttles back and forth in the lines with every foot pump, so the pedal cannot get hard unless it starts hard. The C-ports are there so that after every pump, as the pads wear out, more fluid can enter the line, to "compensate" for the wearing friction surfaces. In a properly working system, rapid multiple pumps will trap the fluid in the lines with a lil more each time, and after a few pumps, the pedal should rise and become hard. When you release the pedal, the relaxing calipers and shoe return springs will force the excess fluid back into the M/C thru the C-ports, and the pedal returns to normal.

Reasons for the C-ports to not return fluid are;
1) it never went out in the first place; like air in the master.
or piston seals leaking allowing the fluid to bypass during application
2) incorrect push-rod length
3) pedal not parking at the top
4) pistons sticking in the mud/rusty bores

You will know that the C-ports are open, by;
a) the fluid roils when you push the pedal down. And
b) the fluid roils again when you return the pedal to the top. and
c) you get a lil geyser after multiple pumps. But be careful; if there is air in the lines, the geyser can be two or three feet high! depending on how many pumps you did, how much air is/might be trapped in the system, and how far out-of-adjustment the rear shoes are; I ain't buying you a paintjob!
 
AJ/FormS said:
If the pedal does NOT get hard with multiple pumpings;
in all likelihood the compensating port is not operating correctly;
or the master is bypassing fluid back into the reservoir,
or, as mentioned, you could have air stuck in the master somewhere.
There is also a slim chance that your new brakes have a mechanical issue.
As to diagnosis; I would
remove the calipers and C-clamp them into the bottom of the bores, then check the pedal. If still soft;
you will have to check that the C-ports are open and the pistons inside are returning to the park position,all the way towards the firewall.
After that, if still soft, I would "bench-bleed" the master, then pressure-test it.

My gut feeling is that the pistons in the M/C are not parking at the back, or the C-ports are restricted/closed. When this happens, the same brake fluid just shuttles back and forth in the lines with every foot pump, so the pedal cannot get hard unless it starts hard. The C-ports are there so that after every pump, as the pads wear out, more fluid can enter the line, to "compensate" for the wearing friction surfaces. In a properly working system, rapid multiple pumps will trap the fluid in the lines with a lil more each time, and after a few pumps, the pedal should rise and become hard. When you release the pedal, the relaxing calipers and shoe return springs will force the excess fluid back into the M/C thru the C-ports, and the pedal returns to normal.

Reasons for the C-ports to not return fluid are;
1) it never went out in the first place; like air in the master.
or piston seals leaking allowing the fluid to bypass during application
2) incorrect push-rod length
3) pedal not parking at the top
4) pistons sticking in the mud/rusty bores

You will know that the C-ports are open, by;
a) the fluid roils when you push the pedal down. And
b) the fluid roils again when you return the pedal to the top. and
c) you get a lil geyser after multiple pumps. But be careful; if there is air in the lines, the geyser can be two or three feet high! depending on how many pumps you did, how much air is/might be trapped in the system, and how far out-of-adjustment the rear shoes are; I ain't buying you a paintjob!
Click to expand...

i know the new front calipers are working properly, even though the pedal isnt rock hard when i had my dad push on the brake pedal the front wheels cannot be turned, when the pedal is released the free spin. Looking under the dash the piston in the master is returning fully to the parked position. When i had the tiny geyser come up in the rear brake chamber i could see the fluid rolling in the front brake chamber.
 
The left rear wheel cylinder has a drop of brake fluid hanging on the bottom of one of the seals and looks like theres some residue in that area. I think im going to replace the wheel cylinders, shoes, hardware and then rebleed the rears and see what happens.
 
Well there you go; bench bleed the master and yur done.

However, just because you cannot turn the front wheels with the brakes applied as you described, does not mean that they are working as designed; it only means, you can't turn them manually.
The calipers do not require much fluid pressure to accomplish that. the pads could be applying on a corner and still do that. And the pads could be bent, warped or installed wrong, hanging up, etc, and so, if you trust your ;
i know the new front calipers are working properly, even though the pedal isn't rock hard when i had my dad push on the brake pedal the front wheels cannot be turned, when the pedal is released they free spin.
Click to expand...
you could be fooled.
C-clamping the pistons eliminates all that.
If you trust your diagnoses on that then OK, move on. But if you're wrong and you buy a new MC, with no change, well...............
 
71DodgeDemon340 said:
The left rear wheel cylinder has a drop of brake fluid hanging on the bottom of one of the seals and looks like theres some residue in that area. I think im going to replace the wheel cylinders, shoes, hardware and then rebleed the rears and see what happens.
Click to expand...
I would
for diagnoses,
just remove the junk and C-clamp the pistons into the bores; you can fix all that after you get the hydraulics back.
In that way you only make one trip to the parts store.
 
AJ/FormS said:
I would
for diagnoses,
just remove the junk and C-clamp the pistons into the bores; you can fix all that after you get the hydraulics back.
In that way you only make one trip to the parts store.
Click to expand...


When the pedal is pushed i can see the calipers move, can definitely tell they are working, everything was installed and lubricated correctly. Im going to start with the wheel cylinders since its obvious one is leaking and go from there. If i have to go through taking the master off i will most likely just upgrade to an aluminum one from dr diff anyway. Ive been feeling like the car hasnt been stopping quite as good as it used to which is why i was upgrading to the 11.75” brakes but it may have been a issue with the rear. Im going to fix the obvious leak first, the rear shoes are starting to crack anyway so might as well do it all. How could there be a mechanical problem with the calipers? As long as they arent leaking and there is no air there shouldnt be a issue right. I only have one c clamp at home so i will have to pick up another to try it but i dont think the issue is in the front brakes
 
How hard is the pedal supposed to be? Will it get rock hard where you cant press it down any further? It gets pretty firm at about the same height as the gas pedal but i can push it further if i try. Also to be clear i havent felt the brakes with the car moving just sitting still
 
71DodgeDemon340 said:
How hard is the pedal supposed to be?
Click to expand...
Kindof depends on what M/C you have but if the big one, yes rock hard.
the tiny one gets too soft for me with power brakes. I like the feel of the 15/16 with a booster. It does not get rock hard, even with braided lines, but has a nice, easily modulated feel.
 
Earlier you said
71DodgeDemon340 said:
i went to go see how the pedal feels and there is some pedal feel but it doesnt get hard until maybe near the floor
Click to expand...
and
71DodgeDemon340 said:
Sitting in the seat i can about force it to the floor and pumping it doesnt seem to help
Click to expand...
and
71DodgeDemon340 said:
But still the pedal doesnt get rock hard. You can feel some resistance but it doesnt change pumping it.
Click to expand...
but now;
71DodgeDemon340 said:
It gets pretty firm at about the same height as the gas pedal but i can push it further if i try
Click to expand...

so what has changed?
 
71DodgeDemon340 said:
when i push the brake pedal the front chamber (rear brake chamber) geysers, fluid squirts up maybe 2” above the reservoir and the rear chamber (front brake chamber) does not. Any thoughts?
Click to expand...
The tall geyser indicates one of two things
a) too much slack in the rear adjusters or
b) air in the rear system.

as to a) if the rear pistons go out a long ways, then when the return springs haul them back it pushes all the fluid back up the line ending in a geyser. For diagnostic purposes I often crank the rear adjusters up hard.
as to b) Air is compressible so if you pump the system up with air in it, it will behave like a big spring when you lift off the pedal, and blow the fluid back into the master.

So now you have a diagnostic tool. If the geyser persists with the rear adjusters cranked hard, I would look for air.
But if it's less or gone, then adjust the rear to normal.

If you clamp all the pistons into the bores front and rear, then the only flex in the system will be the hoses ; so,with braided lines, the pedal will be high and hard, and almost NO geyser is possible unless there is air in the system. So there is another diagnostic tool.
If the pedal becomes high and hard initially, but falls over time, with NO visible leaks, then the MC is bypassing fluid and is no good.

If you have a booster; Do not go two-footed crazy in pressing the pedal; it is possible to break the control valve inside the booster and render it useless.
 
did you bench bleed the master cylinder before hooking up lines and bleeding calipers and wheel cylinders? if not you got air in master cylinder needs to be bench bleed out!
 
In order to do a proper diagnosis we need to know what we are dealing with to begin with. Did your car originally come with disc brakes or is this a recent conversion ?
If so what was there originally and exactly what parts did you change ? Without knowing this, everyone is just throwing darts and hoping something sticks.
 
AJ/FormS said:
Kindof depends on what M/C you have but if the big one, yes rock hard.
the tiny one gets too soft for me with power brakes. I like the feel of the 15/16 with a booster. It does not get rock hard, even with braided lines, but has a nice, easily modulated feel.
Click to expand...


I have a 1-1/32” master
 
MoparLeo said:
In order to do a proper diagnosis we need to know what we are dealing with to begin with. Did your car originally come with disc brakes or is this a recent conversion ?
If so what was there originally and exactly what parts did you change ? Without knowing this, everyone is just throwing darts and hoping something sticks.
Click to expand...


Originally a drum car all the way around, build is 8 years old, did the lbp disk brake conversion with the later spindles and installed 11” ssbc brakes with 2-5/8 slide calipers up front, sbp 8-3/4 rear with 10x1.75 drums.

Just this week upgraded the front to 11.75” slotted rotors and new 2.75 calipers and braided front hoses from dr diff. Rears are still the 10x1.75 drums
 
AJ/FormS said:
Earlier you said

and

and

but now;


so what has changed?
Click to expand...

nothing thats how it was before, i was thinking it needed to feel hard as a rock, its firm after the first few inches about even with the gas pedal but i can push it further, only experience ive had is like pumping the brakes on a car with a vacuum booster, with the engine off once the vacuum is out of the booster the pedal gets hard as a rock, is the manual setup supposed to feel the same?
 
AJ/FormS said:
The tall geyser indicates one of two things
a) too much slack in the rear adjusters or
b) air in the rear system.

as to a) if the rear pistons go out a long ways, then when the return springs haul them back it pushes all the fluid back up the line ending in a geyser. For diagnostic purposes I often crank the rear adjusters up hard.
as to b) Air is compressible so if you pump the system up with air in it, it will behave like a big spring when you lift off the pedal, and blow the fluid back into the master.

So now you have a diagnostic tool. If the geyser persists with the rear adjusters cranked hard, I would look for air.
But if it's less or gone, then adjust the rear to normal.

If you clamp all the pistons into the bores front and rear, then the only flex in the system will be the hoses ; so,with braided lines, the pedal will be high and hard, and almost NO geyser is possible unless there is air in the system. So there is another diagnostic tool.
If the pedal becomes high and hard initially, but falls over time, with NO visible leaks, then the MC is bypassing fluid and is no good.

If you have a booster; Do not go two-footed crazy in pressing the pedal; it is possible to break the control valve inside the booster and render it useless.
Click to expand...


It seems like the rear drum chamber geysers as soon as i first hit the brakes, i can hear a sound when i hit the brake pedal fast, almost like a booster does but it sounds like fluid im assuming its from the geyser hitting the cap
 
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