rear brake drum adjustment clearence drag ? problem ? 74 valiant

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moparjon

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hi , need help or ideas with a brake issue i am having .

trying to get the valiant road / trip worthy for Carlisle on friday morning . which is about a 2 1/2 hours one way . i got a bunch of other stuff done , this is the last thing ( i hope ) . 3 days left .

what has happened so far is i was trying to adjust the brakes ( which , by the way , i have very little experience with ) because they were pulling to one side during braking and a thought they might be dragging. i was kinda in a hurry which i know is not the smartest or safest . so , i backed ALL 4 drums off as far as i could ( the fronts backed off alot , the rears , not much at all . drove it like that for short trips , like 2 to 6 miles and worked ok , as in not dangerous ( i wouldn't drive it if it was ) . stopped well , still pulled a little , but i thought not dragging.

then i took it for about a 40 minute ride , ( moderate amount of braking ) when i got back the rear drums were hot , even the wheel covers were hot , fronts were fine . so i then adjusted the fronts properly ( i think ) . going all the way tight , then backing off till spins freely with a very slight drag .

then i removed the rear wheels , just to have a look and the drivers side drum would not come off . i backed the star adjuster all the way off , which was barely a few turns/clicks and it was still hard to come off but did . passenger side same , but backed off a few turns more .

ok , so here's the thing , with the star adjusters all the way off as much as they can be , and the tops of the shoes tight to the post ( which i think would mean the wheel cylinders are also as far as they can go inward ) . there still does not feel like there is enough clearence . has anybody ever heard of this ? i have not had the car long and don't know what was done to it . i checked the parking brake and it seamed to work fine . brakes got tight , and when released , had slight slack in the cable , and brakes back to where the drum would come off and go back on again .

i left both of them backed off as the one side seamed too tight already , they both did spin a little . like if i grabbed the top a quickly spun it a half turn , it would go another half turn before stopping . but unless i am missing something , is there any other way to get more room ?

i thought of getting the drums cut to get some more space , but is that crazy ? the drums opening is exactly 9 inches with a regular tape measure . ( all i have for measuring ) shoes from outside to outside were about 1/16" less then 9 inches with and even less accurate eyeballing the measuring tape in front of axle . drums appear to be flat ( on countertop , all i have for flatness checking , sorry ) material on shoes looks like they are still thick .

also , i drove it like that for 20 miles and used the brakes almost not at all and all the drums were warm with the drivers rear being slightly warmer . not sure what normal is though , i know there should be some heat .

any thoughts or suggestions ?

i will try to add a few pics . maybe you might see something wrong .

sorry for the run on sentences and rambling , i been out in the hot heat and sun for 4 days now .

thanks !

drum 1.JPG


drum 2.JPG


drum 3.JPG


drum 4.JPG
 
sounds like your rubber brake hoses may need to be changed....They deteriorate over time on the inside and actually swell when you apply the brakes.....then because of the swelling the fluid does not return properly and the brakes actually stay applied some....I would change all three if I was you.....The 2 in the front and also the flex hose on the rear....
 
You do know drums get hot pretty much no matter what, right?
Those look like brand new shoes so it doesn't surprise me that the adjusters are all the way in, and those shoes don't look overheated to me.
What does the drum look like, any blue on it?
If not, run it because the pulling isn't adjustment related but more the surface of the drum and shoe related.
It's also totally possible that since you can back the adjusters all the way off and drive it without the pedal going to the floor that it's probably all new shoes all the way around and they have not "broken in" to the drums yet. (causing tightness and possible pulling)

If you know what you are seeing you can sand the high spots on the shoes to help get them closer to the same curve as the drums and very likely solve both problems at the same time.
 
Jack it up on the diff and apply the brakes. Then try to turn either wheel after releasing very quickly. If it takes a while for the brakes to release then your rubber line is indeed acting like a check valve and should be replaced. Pulling on braking can also be strut rod bushings, control arm bushings, alignment either front end or 4-wheel..... In the old days some shops had equipment to grind your new shoes to match the arc of the drum. Anymore you just set them a little tight and drive it a bit with some hard stops and then check your adjustments or back it up on gravel with some hard stops and let your adjusters do their job.
 
mguner said:
Jack it up on the diff and apply the brakes. Then try to turn either wheel after releasing very quickly. If it takes a while for the brakes to release then your rubber line is indeed acting like a check valve and should be replaced. Pulling on braking can also be strut rod bushings, control arm bushings, alignment either front end or 4-wheel.....
Click to expand...

I was under the impression the pulling was something that started recently (maybe wrong)
And thanks for mentioning the step on the brakes and check it, I forgot to mention that.
 
mguner said:
Jack it up on the diff and apply the brakes. Then try to turn either wheel after releasing very quickly. If it takes a while for the brakes to release then your rubber line is indeed acting like a check valve and should be replaced. Pulling on braking can also be strut rod bushings, control arm bushings, alignment either front end or 4-wheel..... In the old days some shops had equipment to grind your new shoes to match the arc of the drum. Anymore you just set them a little tight and drive it a bit with some hard stops and then check your adjustments or back it up on gravel with some hard stops and let your adjusters do their job.
Click to expand...


Yes that is how you check this.....Once the pedal is released the wheel should spin free immediately......If it doesn't the rubber hoses are bad...
 
mguner said:
Jack it up on the diff and apply the brakes. Then try to turn either wheel after releasing very quickly. If it takes a while for the brakes to release then your rubber line is indeed acting like a check valve and should be replaced. Pulling on braking can also be strut rod bushings, control arm bushings, alignment either front end or 4-wheel..... In the old days some shops had equipment to grind your new shoes to match the arc of the drum. Anymore you just set them a little tight and drive it a bit with some hard stops and then check your adjustments or back it up on gravel with some hard stops and let your adjusters do their job.
Click to expand...


thanks , i will try that . do i need a helper for this test ? , or just jump out and quickly check them after braking ? also , would it matter to test them warmed up or cold ?
 
All the ones I've had do this over the years held pressure long enough that you have time to actually get out and do it yourself. They should release immediately so any residual pressure is a sign of a problem.
 
mguner said:
All the ones I've had do this over the years held pressure long enough that you have time to actually get out and do it yourself. They should release immediately so any residual pressure is a sign of a problem.
Click to expand...
Yeah, mine were that bad too.....
 
mguner said:
All the ones I've had do this over the years held pressure long enough that you have time to actually get out and do it yourself. They should release immediately so any residual pressure is a sign of a problem.
Click to expand...

ok thanks , i pumped the brakes a bit then held them down , then quickly ran back there and they were released . i will try again later , when my helper gets here , to be sure .
 
When it pulls does it also dive either way? In the picture shown I see the primary (short) shoe is in the front as it should be. I trust all are this way....
 
TrailBeast said:
You do know drums get hot pretty much no matter what, right?
Those look like brand new shoes so it doesn't surprise me that the adjusters are all the way in, and those shoes don't look overheated to me.
What does the drum look like, any blue on it?
If not, run it because the pulling isn't adjustment related but more the surface of the drum and shoe related.
It's also totally possible that since you can back the adjusters all the way off and drive it without the pedal going to the floor that it's probably all new shoes all the way around and they have not "broken in" to the drums yet. (causing tightness and possible pulling)

If you know what you are seeing you can sand the high spots on the shoes to help get them closer to the same curve as the drums and very likely solve both problems at the same time.
Click to expand...

not sure exactly what you mean by any blue on it . would it be obvious ? it looks ok to me , can't tell if there is blue , very little if any at all . it might just be the reflection of the gray of the drum , maybe these pics will help . surface is smooth , no gouges / bad grooves / or ridges .

also , do you think it is ok to have the very little clearence ? or should i be concerned ? you think it will break in ?

i think i am gonna do another road test and see what happens . i feel like its probably gonna be ok . unless you think differently . thanks again

drum 7.JPG


drum 9.JPG


drum10.JPG
 
mguner said:
When it pulls does it also dive either way? In the picture shown I see the primary (short) shoe is in the front as it should be. I trust all are this way....
Click to expand...

actually , the pulling pretty much stopped since i adjusted the fronts and backed off the rears . before that i am not sure . with the car going straight , not holding the steering wheel , i would hit the brakes , and the car and steering wheel would swing to the right . now very extremely slightly goes a hair in that direction , but really barely at all . i have not checked the shoes yet .
 
Looks ok to me, and like I said if it's obvious that say only the tips of the shoes are touching the drum you can sand those high spots down some if you are careful to do it flat and a little at a time.

One of the things I do is to sand the drum with a rough paper in a cross hatch pattern so when you apply the brakes it tends to take some of the high spots of the shoes off pretty fast.
Then the drum smooth's down pretty quick from the shoe wearing on it and everything is peachy because the shoe more closely fits the drum and this can solve uneven braking (pulling)
It works kind of like the old arching machines used to do by sanding the shoe arch to fit the drum.

I have to run up town, but if you can post a good pic of a shoe surface I can show you what high spots look like.
Basically it's where the drum only contacts part of the shoe instead of the whole surface (usually the ends)

On the blue comment, overheated drums turn blue from the heat, and sometimes get what are called hot spots.
These are spots of blue or even black in the friction surface for the shoes, and because of the heat the spots are now "tempered" steel and cannot be taken out even by a brake lathe. (too hard)
In these cases the drums are trash.

Yours show no signs of overheating so they would eventually wear in where the shoe contacts the entire surface, but it takes a long time.
That process can be speeded up by the sanding of the shoes and/or drums.
 
TrailBeast said:
Looks ok to me, and like I said if it's obvious that say only the tips of the shoes are touching the drum you can sand those high spots down some if you are careful to do it flat and a little at a time.

One of the things I do is to sand the drum with a rough paper in a cross hatch pattern so when you apply the brakes it tends to take some of the high spots of the shoes off pretty fast.
Then the drum smooth's down pretty quick from the shoe wearing on it and everything is peachy because the shoe more closely fits the drum and this can solve uneven braking (pulling)
It works kind of like the old arching machines used to do by sanding the shoe arch to fit the drum.

I have to run up town, but if you can post a good pic of a shoe surface I can show you what high spots look like.
Basically it's where the drum only contacts part of the shoe instead of the whole surface (usually the ends)

On the blue comment, overheated drums turn blue from the heat, and sometimes get what are called hot spots.
These are spots of blue or even black in the friction surface for the shoes, and because of the heat the spots are now "tempered" steel and cannot be taken out even by a brake lathe. (too hard)
In these cases the drums are trash.

Yours show no signs of overheating so they would eventually wear in where the shoe contacts the entire surface, but it takes a long time.
That process can be speeded up by the sanding of the shoes and/or drums.
Click to expand...


ok cool , try these. when you say rough paper for the drum , how rough ? 80 grit ? , 120 ?

shoe 1.JPG


shoe 2.JPG
 
Hard to tell in the pic if this is brake dust from the center of the shoe gathered at the ends (means only touching the drum in the center of the shoe) or if it's ONLY touching at the ends causing wear marks on the ends.
But you can see how the surface of the shoe is different at the ends (which on new shoes it's usually the center not contacting the drum until the ends wear down.
That uneven surface contact from one corner of your car to another can make a car with new shoes pull to one side, because there is less friction on one brake than the other.
I would sand the drum and let that take some of the high spots on the shoes off, but left alone it would also probably straighten itself out in a couple of hundred miles. (High spots wear down a lot faster than the full flat surface of the shoe)

Since you are one a time limit on leaving for your trip just leave it and go.
(If that is your only concern) they look fine.

shoe 2.JPG
 
update : so far so good did a 20 or so mile trip yesterday was fine until half way after i stopped for 10 minutes somewhere . then brakes were shaking a bit up front . after i got home and 1 hour cooldown , i backed off the fronts a little and drove today for about 14 miles with no problems . gonna do another 20-30 miles tomorrow . so , if all goes well , i will attempt the 160+ drive to Carlisle Mopar show on Friday morning . thanks everybody . see ya there if you're going :)
 
I will be there Saturday....So if your brakes fail down there on Friday, see you Saturday
 
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