73 duster Emergency brake?

-
Thanks, they are not hooked at all.... I'm still having issues with the driver side rear brake locking up first when the brake is applied hard.... Getting ready to change the hoses and proportioning valve...
 
flathead31coupe said:
Thanks, they are not hooked at all.... I'm still having issues with the driver side rear brake locking up first when the brake is applied hard.... Getting ready to change the hoses and proportioning valve...
Click to expand...

The fact one rear brake works indicates pressure is getting to rear.
By your description, the pass side brake is working less effectively than the driver's side.
I'd be looking at the pass rear to see why it's not working as good as the other. Compare both sides looking for something different
Contamination, wheel cyl stuck, adjusted too tight and getting hot, thus losing effectiveness.
Good luck
 
Inertia said:
The fact one rear brake works indicates pressure is getting to rear.
By your description, the pass side brake is working less effectively than the driver's side.
I'd be looking at the pass rear to see why it's not working as good as the other. Compare both sides looking for something different
Contamination, wheel cyl stuck, adjusted too tight and getting hot, thus losing effectiveness.
Good luck
Click to expand...
Thanks,
 
The funny thing is when I first fired up in the morning and I go to back up. I can hear it making a noise like it's. The back is touching a little bit and then when I drive forward and push on the brakes the back lock up.. But release immediately they don't stay locked up
But it only does it a few times until I drive it and then it doesn't do it. Just first thing in the morning.
 
Did you check the rear brakes for broken parts? I've had this happen before, it was a broken spring in the rear drum
 
Brake shoes are self energizing as soon as one shoe touches the drum...... but only in the forward direction.
Take the drum off and post a pic; I bet somebody can spot the problem.

and I bet you can too, if you take the other side off and compare.
 
dmopar74 said:
Did you check the rear brakes for broken parts? I've had this happen before, it was a broken spring in the rear drum
Click to expand...
When I originally got it, it had none of the hardware for the adjusters or anything, so I put the correct Springs and things back on it.
By the time I Get fifty feet or so It doesn't do it anymore
 
I took it for a test drive Again When I push on the brakes hard?It stops quick , but the back do slide both of Them It leaves two black marks
 
that's bad and sortof points to the front brakes NOT WORKING AT ALL.
Is your brake failure warning light on the dash shining red? Does it work?

Look hard, that bulb is not very bright.
It should also come on when you apply the parking-brake.
 
AJ/FormS said:
that's bad and sortof points to the front brakes NOT WORKING AT ALL.
Is your brake failure warning light on the dash shining red? Does it work?

Look hard, that bulb is not very bright.
It should also come on when you apply the parking-brake.
Click to expand...
There is no lights on the - and the light. Does work the brakes work fine? It's just first thing if I let it sit overnight when I back up. I hear one of the brakes grabbing. Just a little and then when I row forward and push on the brakes. The back of lock up after I drive at a few feet.
They won't do it again.... I have jacked the car up in the front and had somebody to push.The brakes and the front wheel stopped so they seem to be working
 
flathead31coupe said:
Again When I push on the brakes hard?It stops quick , but the back do slide both of Them
Click to expand...
See, the key word here is "hard".
Normally, that will cause the fronts to slide.
If the proportioning valve is working, it will be darn near impossible to lock the rear brakes.
Since the dash-light is not on but is known to work, then there are two immediate options to look for.
Firstly, lets prove the electrical circuit is working, then
Secondly, we'll check the plumbing.
1) open the hood and find the Safety switch on the Combination Valve and verify that the circuit works by removing the wire off it and grounding it.
2) turn on the key and look for the red light.
3) if you get the light on, then the circuit is working, and we can assume that the shuttle valve is centered.
4) that sorta points to the valve being plumbed wrong, so
5) As to the Combination-valve.
First, you do have a dual-reservoir master cylinder with TWO brake lines coming out of it right? If true
then, the Combination-Valve, is mounted on the Driver-side apron or frame-rail, close to the firewall, with the knobby-looking thing at the bottom. That thing is the Proportioning-Valve.
Now, as to plumbing.
The reservoir closest to the Firewall should be plumbed to the FRONT brakes, via the TOP of that Combination-valve
The reservoir closest to the rad, should be plumbed to the rear brakes, via the Proportioning valve, and the BOTTOM outlet should be going to the rear brakes.
There is no hydraulic connection inside the Combination valve, between the front and rear systems unless somebody took out the shuttle valve.
The front brake section is just a splitter.

If yours is NOT plumbed this way, then it is wrong and needs to be restored to factory correct.
Check it out, and lemmee know, and from your answer, we can form a new plan.
 
Last edited:
AJ/FormS said:
See, the key word here is "hard".
Normally, that will cause the fronts to slide.
If the proportioning valve is working, it will be darn near impossible to lock the rear brakes.
Since the dash-light is not on but is known to work, then there are two immediate options to look for.
Firstly, lets prove the electrical circuit is working, then
Secondly, we'll check the plumbing.
1) open the hood and find the Safety switch on the Combination Valve and verify that the circuit works by removing the wire off it and grounding it.
2) turn on the key and look for the red light.
3) if you get the light on, then the circuit is working, and we can assume that the shuttle valve is centered.
4) that sorta points to the valve being plumbed wrong, so
5) As to the Combination-valve.
First, you do have a dual-reservoir master cylinder with TWO brake lines coming out of it right? If true
then, the Combination-Valve, is mounted on the Driver-side apron or frame-rail, close to the firewall, with the knobby-looking thing at the bottom. That thing is the Proportioning-Valve.
Now, as to plumbing.
The reservoir closest to the Firewall should be plumbed to the FRONT brakes, via the TOP of that Combination-valve
The reservoir closest to the rad, should be plumbed to the rear brakes, via the Proportioning valve, and the BOTTOM outlet should be going to the rear brakes.
There is no hydraulic connection inside the Combination valve, between the front and rear systems unless somebody took out the shuttle valve.
The front brake section is just a splitter.

If yours is NOT plumbed this way, then it is wrong and needs to be restored to factory correct.
Check it out, and lemmee know, and from your answer, we can form a new plan.
Click to expand...
I did all of the above tests and check the routing of the lines.The light did come on when grounded.And and master cylinder lines are going in the proper location as described... I want to add that if I drive the car just normal and stop normal.I have no issues and after I get rolling a few feet in the morning.There is no issues.It's only when it sits overnight.When I back up I can hear a something draging a little...in the back.. As soon as I.
Hit the brakes for the first time.going forward The back will lock up and then unlock immediately when I let off the pedal.. Then they act normal.
When you drive normal
 
I done a little research and I need to check tomorrow. But it was suggested that I get the smallest wheel cylinder for rear and not use the stock bigger bore cylinder...but I don't know
 
Mopars are rear brake happy, they ALWAYS were with the factory disk front/drum rear. The factory prop valve does not at all make it impossible to lock up the rear brakes, not even close.

The rear drum adjusters advance when the car is traveling in reverse, that's when the adjusters tighten up to keep the rear brakes adjusted.

If you're not reversing in a straight line, one adjuster can adjust more than the other one (because one wheel is traveling further). I found this out myself because I used to park in such a way that I always backed while turning the same direction. This would result in one rear wheel adjusting slightly more frequently than the other, and when that would happen it would lock one rear wheel before the other. The brakes were wearing at the same rate, it just took more time for one of the rear wheels to travel the requisite distance because I was always turning while backing up. This is one advantage that disk brakes have, as they wear they maintain their adjustment constantly. Older drum brakes didn't self adjust at all, you had to do that yourself. The self adjusting brakes on these cars were an improvement, but, they rely on the adjusters and the adjustment is only as fine as the star wheel- so the adjustment of the brakes does vary and can be different side to side because the adjusters are independent of each other.

The adjusters should only be adjusting as the brakes wear. So it shouldn't be something that happens all the time, especially if you just did the brakes, put the adjusters on, and set the adjustment.

Since none of that stuff was hooked up before, it's most likely that something with the adjusters isn't hooked up properly. That's made more so by the fact that the emergency brake isn't hooked up, since it is part of that system even if the brakes should work properly without it being hooked up.
 
72bluNblu said:
Mopars are rear brake happy, they ALWAYS were with the factory disk front/drum rear. The factory prop valve does not at all make it impossible to lock up the rear brakes, not even close.

The rear drum adjusters advance when the car is traveling in reverse, that's when the adjusters tighten up to keep the rear brakes adjusted.

If you're not reversing in a straight line, one adjuster can adjust more than the other one (because one wheel is traveling further). I found this out myself because I used to park in such a way that I always backed while turning the same direction. This would result in one rear wheel adjusting slightly more frequently than the other, and when that would happen it would lock one rear wheel before the other. The brakes were wearing at the same rate, it just took more time for one of the rear wheels to travel the requisite distance because I was always turning while backing up. This is one advantage that disk brakes have, as they wear they maintain their adjustment constantly. Older drum brakes didn't self adjust at all, you had to do that yourself. The self adjusting brakes on these cars were an improvement, but, they rely on the adjusters and the adjustment is only as fine as the star wheel- so the adjustment of the brakes does vary and can be different side to side because the adjusters are independent of each other.

The adjusters should only be adjusting as the brakes wear. So it shouldn't be something that happens all the time, especially if you just did the brakes, put the adjusters on, and set the adjustment.

Since none of that stuff was hooked up before, it's most likely that something with the adjusters isn't hooked up properly. That's made more so by the fact that the emergency brake isn't hooked up, since it is part of that system even if the brakes should work properly without it being hooked up.
Click to expand...
I do back out of my parking spot the same way every time.
Period you could be on to something With the auto adjusting... I have double checked.The brake hardware installation.Everything is installed cobrackley.. So when driving down the street and I push on the brake pedal hard and the back up first.It still stops quick.So the front 1's are working, but I do leave 2 black marks from the rear only.
 
flathead31coupe said:
Factory power breaks disk front drums rear..foward both direction.
Click to expand...

flathead31coupe said:
I do back out of my parking spot the same way every time.
Period you could be on to something With the auto adjusting... I have double checked.The brake hardware installation.Everything is installed cobrackley.. So when driving down the street and I push on the brake pedal hard and the back up first.It still stops quick.So the front 1's are working, but I do leave 2 black marks from the rear only.
Click to expand...


So, to test if this is the adjusters or something else in the brakes, jack the car up and set the rear brake adjustment using the star wheels, make sure that both rear wheels are set with the same clearance. So I adjust the star wheels until the rear brakes just drag on the drums, then back them off one click on the star wheels so the drums spin free. DO NOT BACK UP before you drive. Drive the car and see if the same, single rear brake locks up when you jam on the brakes.

If the same rear brake locks up, you probably have an issue with the brake hoses. If they both lock up equally then the issue you have with one brake locking up after you back up while turning the wheel is likely with the adjusters, and it may not be an "issue" at all, just a circumstance of one wheel adjusting while the other hasn't yet because of the distance traveled in reverse. But it could indicate something wrong with the adjusters, since they should only be adjusting with wear and if you just set them correctly they shouldn't be adjusting all the time.

If both rear brakes are locking up first all the time, you need to consider changing the size of your wheel cylinders. That's not uncommon at all, especially if you're not running the same size wheels and tires on all 4 corners.
 
72bluNblu said:
So, to test if this is the adjusters or something else in the brakes, jack the car up and set the rear brake adjustment using the star wheels, make sure that both rear wheels are set with the same clearance. So I adjust the star wheels until the rear brakes just drag on the drums, then back them off one click on the star wheels so the drums spin free. DO NOT BACK UP before you drive. Drive the car and see if the same, single rear brake locks up when you jam on the brakes.

If the same rear brake locks up, you probably have an issue with the brake hoses. If they both lock up equally then the issue you have with one brake locking up after you back up while turning the wheel is likely with the adjusters, and it may not be an "issue" at all, just a circumstance of one wheel adjusting while the other hasn't yet because of the distance traveled in reverse. But it could indicate something wrong with the adjusters, since they should only be adjusting with wear and if you just set them correctly they shouldn't be adjusting all the time.

If both rear brakes are locking up first all the time, you need to consider changing the size of your wheel cylinders. That's not uncommon at all, especially if you're not running the same size wheels and tires on all 4 corners.
Click to expand...
I am running 15 in the rear in 14.
And the front... I also bought new brake hoses Front end rear and a new proportioning valve.... Justin case Is justin case. The new hoses and proportioning valve have not been installed.
 
Last edited:
Just throwing this in....
Is the P-brake cable relaxed enough for the shoe to be on the pivot pin. A "frozen" cable may cause issues.

1724003606158.png
 
flathead31coupe said:
I am running 15 in the rear in 14.
And the front... I also bought new brake hoses Front end rear and a new proportioning valve.... Justin case Is justin case. The new hoses and proportioning valve have not been installed.
Click to expand...

Sure but what tire sizes? The rim isn't really a big deal, it's the overall tire diameters and widths that really change the braking balance.

The prop valve controls the whole brake balance, but as long as it's working properly replacing it isn't going to change much. Now if it's stuck I suppose that could mess with your front/rear bias, but usually that results in more extreme issues than what you're having. Plus it wouldn't effect a single brake, it would be both rears being altered.

The hoses obviously could affect one side (depending on which hose we're talking about).
flathead31coupe said:
All of that is free and working no tension on e cables
Click to expand...

A picture would be helpful! Not that I don't believe you, but sometimes people miss stuff. I know I certainly have!
 
72bluNblu said:
Sure but what tire sizes? The rim isn't really a big deal, it's the overall tire diameters and widths that really change the braking balance.

The prop valve controls the whole brake balance, but as long as it's working properly replacing it isn't going to change much. Now if it's stuck I suppose that could mess with your front/rear bias, but usually that results in more extreme issues than what you're having. Plus it wouldn't effect a single brake, it would be both rears being altered.

The hoses obviously could affect one side (depending on which hose we're talking about).


A picture would be helpful! Not that I don't believe you, but sometimes people miss stuff. I know I certainly have!
Click to expand...
I'll work on getting some pictures.. Since there's only two brake hoses up front and One brake hose in the rear I bought them Just in case.
 
You must log in or register to reply here.
-

Back
Top