A theory on pulling front drum brakes - I need some schooling!

[RJ Squirrel]

^^^Yeah there ya go- maybe right rear brake locking up?

 

[R413]

Did you machine the drums when the new shoes went on?
Did it ever leak and fluid or greas on the new LF shoes? That will make them brake differenty and want to grab and lock also.


Disconnect end links on bar and drive it.

Control arm bushings and strut rod bushings need looked into.

 

[R413]

Unlikely the rears are doing this, and He has the LF locking up at times.

 

[MoparLeo]

To check for worn/loose strut rods is simple.
Have some one get in your car while you stand to the side at the left and then the right side of the car looking at the front tire in the wheel well.
Have them roll forward and then push on the brake pedal hard and then roll backward and do the same.
Do this on both sides.
If the strut rod bushings are worn out or loose, you will see the wheel actually shift forward or backward in the wheel well when the brakes are applied.

 

[72redbird]

Not sure if the sway bar can do that, but you can disconnect it and try. I would also look at the strut rod bushings. I had a Duster one time that pulled after installing all new shoes, hardware, turning the drums. Turned out to be the rubber brake hose. The inside had collapsed on the opposite side!

 

[moparedtn]

If the sway or strut aren't the issue....
Any possibility of air in or restriction to the RF wheel cylinder?
I believe a rear brake can be a cause of pulling.
Maybe take it out on some compacted gravel and test the wheel lockup of all four.

Not much, actually. All the new lines, cylinders, all that jazz - coupled with bleeding the system all to hell
and back, repeatedly - by both the old two-man and the one-man vacuum methods - should more than
have taken care of things, I'd think.
I know one thing - the shadetree in me was looking for a STRONG stream from each bleeder when I had
my wife manning the pedal - and I got it.
So did the shop floor - and my clothes - and my glasses, etc.

 

[moparedtn]

To check for worn/loose strut rods is simple.
Have some one get in your car while you stand to the side at the left and then the right side of the car looking at the front tire in the wheel well.
Have them roll forward and then push on the brake pedal hard and then roll backward and do the same.
Do this on both sides.
If the strut rod bushings are worn out or loose, you will see the wheel actually shift forward or backward in the wheel well when the brakes are applied.

Excellent advice, thank you! I had not thought of that.
I would imagine this is similar to the late-model LX based cars (Challenger, Charger) as well, since they also have
strut bars sort of like these old cars - and I HAVE witnessed what a bad strut rod bushing acts like on one of those
(happened on our old 2006 Charger at shockingly low miles), so I know sort of what to look for.

 

[moparedtn]

Did you machine the drums when the new shoes went on?
Did it ever leak and fluid or greas on the new LF shoes? That will make them brake differenty and want to grab and lock also.


Disconnect end links on bar and drive it.

Control arm bushings and strut rod bushings need looked into.

No no, I'm very sanitary about all that....

 

[moparedtn]

Not sure if the sway bar can do that, but you can disconnect it and try. I would also look at the strut rod bushings. I had a Duster one time that pulled after installing all new shoes, hardware, turning the drums. Turned out to be the rubber brake hose. The inside had collapsed on the opposite side!

New hoses on this rascal; that was a no-brainer. Seen bad hoses in the past...

 

[kiwigtx]

At the risk of being shot down in flames. Two things I would double-check and verify before any alignment money is spent....

1. Check the length of each of the front strut rods. I discovered many years ago someone machined one about 3/4" shorter to make the alignment appear OK. It did however get picked up and addressed....but only after many prematurely worn-out tires and uneven braking situations.

2. Do a thorough chassis measurement - point to point diagonally. This will prove that the chassis is indeed square after the previous incident was remedied.
No alignment will ever be correct until the chassis is proven to be square and straight. Saying it's straight means nothing without the measurements.

 

[oldbee]

Not sure if the sway bar can do that, but you can disconnect it and try. I would also look at the strut rod bushings. I had a Duster one time that pulled after installing all new shoes, hardware, turning the drums. Turned out to be the rubber brake hose. The inside had collapsed on the opposite side!

My thought exactly, but I thought Fred had all new parts everywhere (?)

 

[moparedtn]

At the risk of being shot down in flames. Two things I would double-check and verify before any alignment money is spent....

1. Check the length of each of the front strut rods. I discovered many years ago someone machined one about 3/4" shorter to make the alignment appear OK. It did however get picked up and addressed....but only after many prematurely worn-out tires and uneven braking situations.

2. Do a thorough chassis measurement - point to point diagonally. This will prove that the chassis is indeed square after the previous incident was remedied.
No alignment will ever be correct until the chassis is proven to be square and straight. Saying it's straight means nothing without the measurements.

1. They're the originals. Hope they're the same length.
2. Did that - see previous posts. The car is amazingly "square" - the alignment guy commented that they're not
that close to perfect on the diagonals unless they've spent time on a frame machine/jig - which Fred never has.

 

[moparedtn]

My thought exactly, but I thought Fred had all new parts everywhere (?)

He does - and I spent a lot of time hunting down new USA-made stuff from olden days, when they actually
still made decent parts. Zero foreign or "modern" parts were used anywhere, short of the Porterfield shoes
(made in California).

 

[moparedtn]

Thanks to you all, there's a three step process forming here...
1. Do the "strut rod test" as described by y'all
2. Take the car in to the alignment guy, to be gone over by he (and I!) with big-arse
steel bars and such to check components - then the alignment numbers pulled again
3. Get a dang straight sway bar on the car regardless - provided I can find one,
of course!

 

[oldbee]

Thanks to you all, there's a three step process forming here...
1. Do the "strut rod test" as described by y'all
2. Take the car in to the alignment guy, to be gone over by he (and I!) with big-arse
steel bars and such to check components - then the alignment numbers pulled again
3. Get a dang straight sway bar on the car regardless - provided I can find one,
of course!

Just something to think about,,, many years ago my front end guy told me it doesn’t take much to knock out the alignment if you hit anything if the wheels aren’t going straight ahead. Park lot bumpers,potholes,etc.

 

[dvw]

This will assume the front end components and alignment are in good shape. I was an auto tech from 1974 and still do work on the side. Did 100's of drum jobs back in the 70's. Occasionally we would get a tough to diagnose pull. I quickly learned to swap the shoes and drums side to side. If the pull changed sides. Then swap the drums back and recheck. We are talking drums that measure within .010" diameter with a very nice surface finish. this would quickly rule out shoes and drums. I was also taught to fit the shoe against the drum. If the shoe touched only at the center? You laid the shoe down on the ground an gave it a smack in the center with a hammer to open it up. If it only touched on the ends? Put the bottom of the shoe on the ground and wack the top to give it a little less bow. Doesn't take much. They move pretty easily. Last thoughts. Make sure the wheel cylinders aren't sticking. The backing plate pads where the shoes set aren't grooved/rusty, and the flex hoses are in good shape.
Doug

 

[pnora]

Thanks to you all, there's a three step process forming here...
1. Do the "strut rod test" as described by y'all
2. Take the car in to the alignment guy, to be gone over by he (and I!) with big-arse
steel bars and such to check components - then the alignment numbers pulled again
3. Get a dang straight sway bar on the car regardless - provided I can find one,
of course!

How much is that bar off? Unless it is off a lot it will be a waste of time. Here is one thing to keep in mind. If the bar was perfect and the car was level so the bar fit perfect, like a neutral fit with no preload.......What happens when you sit in the car? You have now loaded the bar. Maybe the little you see is what was engineered into it.

 

[Daves69]

FWIW,
Might be interesting to check difference in the drum temps after some heavy braking.

Old school way was to arc the shoes to match the drums after turning. That was a dirty job as I recall.

 

[moparedtn]

This will assume the front end components and alignment are in good shape. I was an auto tech from 1974 and still do work on the side. Did 100's of drum jobs back in the 70's. Occasionally we would get a tough to diagnose pull. I quickly learned to swap the shoes and drums side to side. If the pull changed sides. Then swap the drums back and recheck. We are talking drums that measure within .010" diameter with a very nice surface finish. this would quickly rule out shoes and drums. I was also taught to fit the shoe against the drum. If the shoe touched only at the center? You laid the shoe down on the ground an gave it a smack in the center with a hammer to open it up. If it only touched on the ends? Put the bottom of the shoe on the ground and wack the top to give it a little less bow. Doesn't take much. They move pretty easily. Last thoughts. Make sure the wheel cylinders aren't sticking. The backing plate pads where the shoes set aren't grooved/rusty, and the flex hoses are in good shape.
Doug

Already did the swapping of drums, etc. and parts are all new, Doug (see prior answers). thanks!

How much is that bar off? Unless it is off a lot it will be a waste of time. Here is one thing to keep in mind. If the bar was perfect and the car was level so the bar fit perfect, like a neutral fit with no preload.......What happens when you sit in the car? You have now loaded the bar. Maybe the little you see is what was engineered into it.

Bar is off considerably...I wouldn't fuss about a little off.

FWIW,
Might be interesting to check difference in the drum temps after some heavy braking.

Old school way was to arc the shoes to match the drums after turning. That was a dirty job as I recall.

The left side would get HOT after one of the "pulling sessions", every time. Makes sense it would.
Swapping of drums (I have 4 of those old 11x3 drums to choose from and they've all been on the car
in both front positions at one time or another).

 

[R413]

Have any drums been machined or turned or are you using glazed drums?

That can be a problem, but it would change with swapping drums and different drums.

The arcing of the shoes to the drum is a real thing. You could be using only half of the shoe surface on a drum that has been machined bigger.