Brake Proportioning

Rifleshooter

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Hello all. With the recent snow I've come to notice that the brakes on my 80 volare are all out of wack. I have a manual brake system and the rear brakes are clearly catching before the front brakes and above all else the right rear brake catches first out of all of them. Isn't there a way to play with my brake proportioning valves both at the master cylinder and at my rear to get them to where they're supposed to be? If there is how can I tell if I got it right? Please help!
 

78VOLAREWAG

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Hello all. With the recent snow I've come to notice that the brakes on my 80 volare are all out of wack. I have a manual brake system and the rear brakes are clearly catching before the front brakes and above all else the right rear brake catches first out of all of them. Isn't there a way to play with my brake proportioning valves both at the master cylinder and at my rear to get them to where they're supposed to be? If there is how can I tell if I got it right? Please help!
A bad Hose will cause problems like that.
 

AJ/FormS

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Q1) Are your front brakes working?..... They are discs right?
Q2) What tires front and rear?
Q3) Is the car wanting to spin out of control?
Q4) Do you get a hard pedal when pressing down hard?
Q5) What size rear W/Cs did you install?, they are part of the proportioning system.
Q6) Did you install the disc brake M/C?
Q8) Did you plumb it correctly?
The large reservoir goes to the front brakes.
Q9) Did you change anything at the combination valve?
The top of it should go to the front brakes. The rear brakes should be plumbed to the bottom side-port. The very top end-port should go to the larger front brake reservoir.
Q10) There should be no brake warning lite lit up on the dash until the park brake lever is pulled, for testing purposes. Is this how your system works?
Q11) Does the park-brake fully release on its own? You may need to remove the wheels and drums to witness the lever returning all the way to it's parked position.

If the park brake system is working properly;
The adjuster at the right rear will have to be backed off about 10 clicks, and the left adjuster tightened about 3 to 5, I'm guessing.

If you can't skid the front tires at 20mph on dry pavement, you have a problem there, and we need to fix that first.
 
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Rifleshooter

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I cannot get the fronts to lock at all but I can clearly feel when they catch so they are working. It's front disc and rear drum, I didn't switch the lines into or out of the master cylinder or the combo valve. THe brakes are blead properly as I do get a hard pedal when braking. And the parking brake is probably a little too loose if anything. It only ever really holds when it's all but at the floor.
 

AJ/FormS

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Ok I can see 7 or 8 or 9 problems,
Please go to the bottom of this post, and click on quote,then transfer the quote into the new reply box, and answer as many questions inside the quote as you can, and then we'll review it together. You can use a non-black color to make the answers easy to see.
Then outside the quote, you can call me an azzhole if you want to, or any other favorite adjective..

Q1) Are your front brakes working?..... but I can clearly feel when they catch so they are working
They are discs right? It's front disc and rear drum
Q2) What tires front and rear?
Q3) Is the car wanting to spin out of control?
Q4) Do you get a hard pedal when pressing down hard?I do get a hard pedal when braking
Q5) What size rear W/Cs did you install?, they are part of the proportioning system.
Q6) Did you install the disc brake M/C?
Q8) Did you plumb it correctly?
The large reservoir goes to the front brakes.
Q9) Did you change anything at the combination valve?
The top of it should go to the front brakes. The rear brakes should be plumbed to the bottom side-port. The very top end-port should go to the larger front brake reservoir.I didn't switch the lines into or out of the master cylinder or the combo valve.
Q10) There should be no brake warning lite lit up on the dash until the park brake lever is pulled, for testing purposes. Is this how your system works?the parking brake is probably a little too loose if anything. It only ever really holds when it's all but at the floor.
Q11) Does the park-brake fully release on its own? You may need to remove the wheels and drums to witness the lever returning all the way to it's parked position.

If the park brake system is working properly;
The adjuster at the right rear will have to be backed off about 10 clicks, and the left adjuster tightened about 3 to 5, I'm guessing.

If you can't skid the front tires at 20mph on dry pavement, you have a problem there, and we need to fix that first.I cannot get the fronts to lock at all
 
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Rifleshooter

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Q2: Front 195/75R14 Rear 215/70R14
Q3: it's hard to say since the braking is so shitty from the get go.
Q5: the rear Wheel Cylinders I put on were stock replacements.
Q6: please translate M/C
Q7 MIA haha
Q8: yes I did
Q11: yes it releases entirely on its own.
 

AJ/FormS

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Your front brakes are not working correctly, so they are the number one thing. The reason the back is skidding is because you are pushing too hard on account of the fronts are lazy. But to figure out why, I need you to answer the other questions, or else I'll be making you do all kinds of tests and it's cold outside.
 

Rifleshooter

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Your front brakes are not working correctly, so they are the number one thing. The reason the back is skidding is because you are pushing too hard on account of the fronts are lazy. But to figure out why, I need you to answer the other questions, or else I'll be making you do all kinds of tests and it's cold outside.
I answered as many as I could.
 

AJ/FormS

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Ok I can see 7 or 8 or 9 problems,
Please go to the bottom of this post, and click on quote,then transfer the quote into the new reply box, and answer as many questions inside the quote as you can, and then we'll review it together. You can use a non-black color to make the answers easy to see.
Then outside the quote, you can call me an azzhole if you want to, or any other favorite adjective..

Q1) Are your front brakes working?.....
I can clearly feel when they catch so they are working.
But you can't skid the tires

They are discs right?
It's front disc and rear drum

Q2) What tires front and rear?
Front 195/75R14 Rear 215/70R14
Q3) Is the car wanting to spin out of control?
it's hard to say since the braking is so shitty from the get go.
So I'll take that as a no, meaning the front is doing something

Q4) Do you get a hard pedal when pressing down hard?
I do get a hard pedal when braking
This is a good thing

Q5) What size rear W/Cs did you install?, they are part of the proportioning system.
the rear Wheel Cylinders I put on were stock replacements.
stock what? 13/16 or 7/8, or 15/16

Q6) Did you install the disc brake M/C?please translate M/C
This is master cylinder

Q8) Did you plumb it correctly?
yes I did
The large reservoir goes to the front brakes.
Q9) Did you change anything at the combination valve? The top of it should go to the front brakes. The rear brakes should be plumbed to the bottom side-port. The very top end-port should go to the larger front brake reservoir.I didn't switch the lines into or out of the master cylinder or the combo valve.But you didn't verify that they were correct to begin with
Q10) There should be no brake warning lite lit up on the dash until the park brake lever is pulled, for testing purposes. Is this how your system works?
the parking brake is probably a little too loose if anything. It only ever really holds when it's all but at the floor.
But you didn't verify that the levers and struts were fully retracted
inside the drums
Q11) Does the park-brake fully release on its own?
yes it releases entirely on its own.
At least the part in the cab does

You may need to remove the wheels and drums to witness the lever returning all the way to it's parked position.

If the park brake system is working properly;
The adjuster at the right rear will have to be backed off about 10 clicks, and the left adjuster tightened about 3 to 5, I'm guessing.

If you can't skid the front tires at 20mph on dry pavement, you have a problem there, and we need to fix that first.
I cannot get the fronts to lock at all
Then you have a dangerous problem, and we have to fix this ASAP!
 

AJ/FormS

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We need to get Q6 clarified.
The db M/C (disc brake Master Cylinder), has a large reservoir supplying the fluid to the front brakes and it has no valving inside the port. The reservoir for the rear brakes is waaaay smaller, and if you look inside the port you will see a little brass valve. No don't go look for it,lol. If you have a big and little reservoir, then we are on the right track.

The M/C for drums usually has two same sized reservoirs, and is wrong for a db car.

So which do you have?
 
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Rifleshooter

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New front rotors, pads, wheel bearings, and brake hoses all done together. The calipers were not seized as the returned freely.
 

AJ/FormS

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Q6) Did you install the disc brake M/C?please translate M/C
This is master cylinder

We need to get Q6 clarified.
The db M/C (disc brake Master Cylinder), has a large reservoir supplying the fluid to the front brakes and it has no valving inside the port. The reservoir for the rear brakes is waaaay smaller, and if you look inside the port you will see a little brass valve. No don't go look for it,lol. If you have a big and little reservoir, then we are on the right track.

The M/C for drums usually has two same sized reservoirs, and is wrong for a db car.

So which do you have?
 
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AJ/FormS

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Yes I replaced it. And made sure the replacement was an exact match to the original.
And so what did it look like? Look you're car is thirty-five years old, help me out! Answer the questions please
New front rotors, pads, wheel bearings, and brake hoses all done together. The calipers were not seized as the returned freely.
Ok now we're getting somewhere.
When this car was new, it was well able to skid those skinny rollers at 20 mph. So the question is why can't yours? What is different about the parts you installed?
It is obvious to me that there is a problem in the front system.
Lets list what is new; booster,M/C,hoses, rotors,pads, and wheel bearings.
Let's list what is not new; calipers, caliper brackets, and hard lines.
Let's list what else we know; pedal is hard,caliper pistons were easy to return, and it has fresh brake fluid. And; the pads will not put a serious clamp on the rotors.
Ok so:
it could have a hydraulic problem, or it could have a mechanical /install problem.
If hydraulic, it could be;
H1)a bad M/C,
H2) or stuck caliper pistons
H3) or restricted lines.
H4) Or the energy from your foot is not getting to the M/C,
H5) or the most common, is a big old air bubble inside the M/C cuz it wasn't properly bench-bled.
H6) Or, it could be that the compensating port is not returning fluid properly and the front brakes are dragging and boiling the fluid
If mechanical,it could be;
M1) loose wheel bearings, knocking the pistons back into the bores,
M2) or pads installed wrong side to the rotor,
M3) or the calipers stuck on the slider pins or on the brackets and not getting out to the rotors,
M4) or the pads not contacting the rotors over their full faces,
M5) or only one pad per side braking.
M6) or those used caliper-pistons ain't coming to work.

So lets review;
you said yes to hard pedal. if true, this would tend to rule out;H1,H5,and H6. It would also rule out M1,M4,and M5. Boy that was easy,right? We're halfway done.
You said; the pistons went back into the bores easy. If the calipers are in fact clean and loose inside, then that would rule out H2
You said bled,bled, and more bled. If you did it right, That would tend to rule out H3 and H6, leaving only H4, as a hydraulic problem.
Now as to the remaining mechanical possibilities,namely M2,M3,and M6; M2 is unlikely, in that it is unlikely that you would have done it to both sides. And M6, is unlikely if you pushed them in with your thumbs. That leaves just M3, and is a common beginners mistake. The pins need to be straight and smooth and lubed with rubber o-ring lube.The pins have to slide freely thru the caliper holes provided.Often the O-rings in there have to be removed and the grooves cleaned of all the years of accumulated rusty slag. As to the caliper ways. These accept the brake torque and transmit it into the knuckle and eventually into the frame. If the pads have dug deep grooves in them, then they will get stuck in there, and what little brake torque there is will keep them from climbing out. I have had to repair many,many,many slide ways, by hard brazing metal into the grooves and then filing it flat.
So now we are stuck with just M3 and H4,
H4 is an easy test, so let's do that first. Climb in and pump the brake pedal up and down (it doesn't have to be hard) about 10 times. Then push it down and hold it down with about 50 pounds of foot pressure,like you were preparing to climb up the stairs, but not enough to actually go.I use both legs, to make it easier cuz this is a long test.The pedal should be very hard with no sponginess. Then start up the engine. The brake pedal should immediately begin to fall as the engine comes to life. Wait about 5 seconds for it to stabilize.This proves the booster is multiplying your foot pressure, making it easier for you to achieve a lotta hydraulic pressure. The pedal should stop moving and remain at that pedal height forever. Or for as long as you continue with the same pedal pressure. If the pedal slowly sinks to the bottom and then gets hard again, the M/C is no good, it has an internal leak.. But if it remains at a fixed height,for a minute or so, then you can end the test .And so H4 is a pass, leaving just M3.
For M3 you will have to remove the calipers and pads again, and check the ways and pins as described above. And repair them as may be necessary. since the wheels are off, this is a good time to reset the wheel-bearing preload adjustment
And then it's roadtest time again.
Now please notice where I said "you said". I based my answer on what "you said". If you told me wrong or left something out, I mightof offered another solution.
It could also be that I missed something, and another mechanic will come along and mention it. I'm only human, and I make mistakes too.
You can go over the list yourself and go down some of those other roads, like back-tracking.
If you get M3 repaired and it still won't skid the tires at 20mph, then we're not finished! Then you will have to do a hydraulic pressure test. It is your last option.
I leave it for last, cuz you will need to plumb into the bleeder hole with a high pressure gauge of at least 1200psi.Mo-money,lol. It may be that the hard lines are clogged.
Personally I would do this test first, cuz I already have the tester,lol.

You did bench-bleed the M/C right?,lol.
done
 
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78VOLAREWAG

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My brother had a 76 Dart, right rear wheel kept locking up. I checked every thing I could think of, everything checked good. Someone said REAR hose, I didn't believe them, so my brother took it to the garage that replaced the hose, cured the problem.
 

Rifleshooter

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And so what did it look like? Look you're car is thirty-five years old, help me out! Answer the questions please

Ok now we're getting somewhere.
When this car was new, it was well able to skid those skinny rollers at 20 mph. So the question is why can't yours? What is different about the parts you installed?
It is obvious to me that there is a problem in the front system.
Lets list what is new; booster,M/C,hoses, rotors,pads, and wheel bearings.
Let's list what is not new; calipers, caliper brackets, and hard lines.
Let's list what else we know; pedal is hard,caliper pistons were easy to return, and it has fresh brake fluid. And; the pads will not put a serious clamp on the rotors.
Ok so:
it could have a hydraulic problem, or it could have a mechanical /install problem.
If hydraulic, it could be;
H1)a bad M/C,
H2) or stuck caliper pistons
H3) or restricted lines.
H4) Or the energy from your foot is not getting to the M/C,
H5) or the most common, is a big old air bubble inside the M/C cuz it wasn't properly bench-bled.
H6) Or, it could be that the compensating port is not returning fluid properly and the front brakes are dragging and boiling the fluid

If mechanical,it could be;
M1) loose wheel bearings, knocking the pistons back into the bores,
M2) or pads installed wrong side to the rotor,
M3) or the pads stuck in the caliper brackets and not getting out to the rotors,
M4) or the pads not contacting the rotors over their full faces,
M5) or only one pad per side braking.
M6) or those used caliper-pistons ain't coming to work.

So lets review; you said yes to hard pedal. if true, this would rule out;H1,H5,and H6. It would also rule out M1,M4,and M5. Boy that was easy,right? We're halway done.



To be continued
I have a manually operated brake system. Aka no brake booster. All the brake parts I've replaced are exact matches to the parts that came off. I blead the MC correctly and even went to the extent of having a few coworkers double check it(I'm a mechanic that works at a Firestone). The wheel bearing are brand new and tight. The caliper pistons work properly(provent when bleeding the brakes). And the pads were replaced to match what was there originally.
 
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